EXPERIMENT 9 ENTHALPY OF REACTION HESS S LAW

Size: px
Start display at page:

Download "EXPERIMENT 9 ENTHALPY OF REACTION HESS S LAW"

Transcription

1 EXPERIMENT 9 ENTHALPY OF REACTION HESS S LAW INTRODUCTION Chemical changes are generally accompanied by energy changes; energy is absorbed or evolved, usually as heat. Breaking chemical bonds in reactants requires energy, and energy is released as new bonds form in products. Whether the combination of these steps absorbs or releases energy depends on the relative sizes of the energies associated with breaking and forming bonds. The amount of heat involved in a reaction depends not only on what the reaction is, but also on the temperature at which the reaction occurs and whether the reaction occurs under conditions of constant pressure or constant volume. In the laboratory, many reactions are conveniently carried out at constant pressure in beakers or flasks that are open to the atmosphere. The amount of heat absorbed or released under this condition is the enthalpy change, H, for the reaction, where H = Hproducts - Hreactants (9-1) Enthalpy, H, can be thought of as the heat content of a substance; this heat is stored as potential energy in the form of bond, and other, energies. When atoms rearrange during a reaction, the heat content of the products is usually different from the heat content of the reactants. This difference in heat content appears as heat absorbed or released. This heat is generally indicated in Joules for the reaction as written. For example, in this experiment you will examine an acid-base neutralization in aqueous solution: H3O + (aq) + OH - (aq) 2 H2O(l) H = -55.8kJ (9-2) The enthalpy change for this reaction could be given in J/(mol of H 3O + ), or in J/(mol of OH ), or in J/(mol of H 2O). To avoid confusion it is customary to report H for the reaction with the numbers of moles of reactants and products simply as written. Thus, for reaction 9.2, in which 1 mole of H 3O + and 1 mole of OH combine to form 2 moles of H 2O, H = kj, as shown. Note that the enthalpy change, H = H products H reactants, is positive if heat is absorbed; that is, if H products > H reactants, the reaction is endothermic. The enthalpy change is negative if heat is released. If H products < H reactants, the reaction is exothermic. This is illustrated in the following diagrams: products reactants H heat absorbed H heat evolved reactants H > 0 (endothermic) products H < 0 (exothermic) Experiment 9 9-1

2 In an exothermic reaction, the overall process causes the system to become more energetically stable; excess energy is released as heat. The system changes from a higher energy state to a lower energy state. It seems plausible intuitively that reactions would have a natural tendency to proceed spontaneously to a state of lower energy; in fact, a negative enthalpy change is part of what causes some reactions to occur spontaneously. Physical changes also have associated enthalpy changes. For the melting of water, for example: H2O(s) H2O(l) H = + 6.1kJ (9-3) In this process, no chemical bonds are broken or formed. The energy input converts the potential energy from that characteristic of the rigid solid-state organization of water molecules to that characteristic of the liquid state, in which water molecules move over, under, and around one another, but are still held together in a relatively small volume. Similarly, enthalpy changes accompany the dissolving of solids or the dilution of solutions. For example, when AlCl 3(s) dissolves in water, the Al 3+ and Cl ions must be separated. In the solid state they are packed together in a way that results in the greatest stability (cations surrounded by anions and vice versa). In liquid water the water molecules are extensively H-bonded to one another. They must be separated to create cavities for the Al 3+ and Cl ions to occupy. Both of these processes cost energy, i.e., they are endothermic. In contrast, energy is released when Al 3+ ions are hydrated, becoming closely surrounded by the negative ends of six polar water molecules in solution. Similar interaction of Cl ions with the positive ends of polar water molecules also releases energy. The balance among the energies for all these processes determines whether the overall H solution for AlCl 3 will be positive or negative. (It turns out to be negative.) Enthalpy is one member of an important class of thermodynamic functions known as state functions. A state function has the unique characteristic that its value for a system does not depend upon the history of the system. No matter how a system was formed, the value for any state function depends only on the present state of the system. This has the extremely useful practical consequence that the change in any state function for a process depends only on the initial and final states and thus is independent of the pathway by which the process takes the system from the initial state to the final state. Another way of stating this for enthalpy is in the form of Hess s Law of Constant Heat Summation: If a reaction (or physical process) is carried out in a series of steps, H for the overall process is equal to the sum of the enthalpy changes for the individual steps. It is a consequence of Hess s Law that, as long as we begin with the reactants in one particular state (given temperature, etc.) and end with the products in another particular state, the overall H rxn is the same, no matter what individual steps are carried out, or in what order, to convert the reactants to the products. We will examine how well this principle holds for two different chemical reactions in this experiment. TECHNIQUE Calorimetry is the measurement of the heat change for a reaction, and the device used to measure heat changes is a calorimeter. In this experiment, the calorimeter consists of two nested Styrofoam cups with a MeasureNet temperature probe inserted into the cup to monitor the temperature. If the reaction is exothermic, the heat released, which will ultimately be transferred to the surroundings, is temporarily trapped by the insulating walls of the Styrofoam cups and causes the temperature of the calorimeter contents to rise. For an endothermic reaction, the temperature of the calorimeter contents falls. The Styrofoam cups temporarily prevent heat from entering the system from the surroundings, and the calorimeter contents must supply the heat absorbed in the process. In either case, the size of the temperature change is used to determine the quantity of heat released or absorbed. Experiment 9 9-2

3 The amount of heat released or absorbed is related to the temperature change by the equation q m c T C T (9-4) where q = amount of heat, m = mass of material undergoing the temperature change, c = specific heat of the material undergoing the temperature change, T = temperature change = T final T initial, and C = m c = heat capacity of the material undergoing the temperature change. In highly accurate calorimetric measurements, it is necessary to consider contributions to the heat capacity, C, from the solution present, the calorimeter walls, and even the temperature probe itself (that is, everything which undergoes the temperature change). While heat capacity data for many solutions can be taken from tables in chemical handbooks, calorimeters and temperature probes differ, so their contributions to C must be determined experimentally. (In practice the total heat capacity of calorimeter and contents is determined by measuring the temperature change caused by adding a known amount of heat with an electrical heating device.) We will greatly simplify the analysis by means of reasonable approximations: 1. We ignore the small contributions from the calorimeter walls and temperature probe. 2. We estimate the heat capacity of the calorimeter contents by considering only the amount of water present and treating any solution added as though it were just water with a density of g/ml. This works fairly well since, although the separate values of m and c for a solution are different from m and c for an equal volume of pure water, the product m c changes little. So, in this experiment we will approximate the specific heat of all solutions as J/( C g of water present). As EQUATION 9-4 indicates, q (the amount of heat absorbed or evolved) is proportional to T. It is often quite simple to measure T. If no heat escapes from or enters the calorimeter from outside, we need only to measure T initial, mix the reactants, and then measure T final. If the temperature in the calorimeter is close to room temperature and T is small, this works well. This situation is illustrated in FIGURE 9-1, in which an endothermic process takes place (step 1, from T 2 to T 3), followed by an exothermic process (step 2, from T 3 to T 4). The entire temperature range shown is less than 5 C, so the temperature is always close to room temperature. The lack of drift is evident in the data, from the essentially constant values before and after each of the processes. (The temperature scale is greatly expanded in FIGURE 9-1, so even nearly constant values may appear to be changing a little.) The interpretation of FIGURE 9-1, particularly with regard to the labeled temperatures, T 1 through T 4, is discussed in the Results section of the handout. We must be careful with the sign of T when we use it to determine H for the process. When T is negative, the value of q obtained from EQUATION 9-3 will also be negative. As discussed above, a negative T is the result of the occurrence of an endothermic process, for which H is positive. Similarly, a positive T results from an exothermic process, for which H is negative. Therefore, in general, Hprocess = -q (9-5) Experiment 9 9-3

4 T1 = C T2 = C T4 = C T3 = C Figure 9-1. Temperature vs. time plot for two-step experiment. OBJECTIVES to determine the temperature changes for a series of chemical processes to determine the enthalpy changes for the chemical processes to compare the enthalpy changes with available literature values to test the validity of Hess s Law EQUIPMENT NEEDED 100-mL beaker 8-oz. Styrofoam cups (2) 100-mL graduated cylinders (2) temperature probe MeasureNet CHEMICALS NEEDED distilled water NH 4Cl(s); ammonium chloride 1.00 M HCl; hydrochloric acid 1.00 M NaOH; sodium hydroxide NaOH(s); sodium hydroxide PROCEDURE The measurements in this experiment can be carried out in a relatively short time. However, the analysis and interpretation of the results will probably take somewhat longer. Therefore, before you spend any time on the analysis, be sure that you have data of adequate quality. Show the plots you obtain in the steps below to your instructor for his/her comments and approval. There should be plenty of time (should your instructor advise it) to Experiment 9 9-4

5 simply repeat one or more of your measurements. In that case, discard the defective results and replace them with the new. A. Enthalpy Changes NH4Cl and NaOH Reaction In this part of the experiment you will compare two different pathways for carrying out the following overall process: NH 4Cl(s, g) + H 2O(l, 50 ml) + NaOH(aq, 1.00M, 50 ml) NH 3(aq) + NaCl (aq) (9-6) Notice that g of NH 4Cl contains mol of NH 4Cl, and that 50 ml of 1.00M NaOH solution contains mol of NaOH. Therefore, mol of NH 3 and mol of NaCl will be formed when the reaction occurs. In the first pathway (call it SOLID FIRST), you will first dissolve the NH 4Cl in the water, recording any temperature changes that occur, and then add the NaOH solution to the NH 4Cl solution, while continuing to record any temperature changes occurring. (The resulting plot of temperature versus time should resemble FIGURE 9-1.) In the second pathway (call it SOLID LAST), you will reverse the order (first adding the NaOH solution to the water and then dissolving the NH 4Cl in the resulting diluted NaOH solution). Note especially that both pathways have the same starting and ending points. Thus this experiment will provide data allowing you to test the validity of Hess s Law. Setting up the Temperature Probe 1. Press MAIN MENU on the workstation, select TEMPERATURE, then TEMP V TIME. The display should confirm that you have selected temperature and list options now available to you. Press SETUP, then choose SET LIMITS FOR NEW ACQUISITION. Follow the instructions on the display to set the temperature (y) limits at 10 C and 40 C and the time (maximum x) limit at 300 seconds. Leave the minimum time setting at 0. Press DISPLAY. The display should now show an empty graph with the values 10 and 40 along the y-axis. Since we will be investigating changes in temperature, it will not be necessary to calibrate the temperature probe, as long as it is reading C while plugged into the workstation and exposed to the lab atmosphere. A.1. SOLID FIRST Path a. Set up the calorimeter by nesting two Styrofoam cups together. Obtain ~100mL of 1.0 M NaOH solution and ~200 ml of distilled water in separate beakers. b. Use separate graduated cylinders to measure 50.0 ml of distilled water and 50.0 ml of 1.0 M NaOH. Pour the distilled water into the calorimeter. c. Carefully weigh out as close to g of NH 4Cl as possible, within (0.005 g) using the top-loading balance. d. Press START/STOP to begin collecting data. Place the temperature probe in the solution in the graduated cylinder containing NaOH solution and begin stirring until the temperature reading is fairly steady. Record its temperature. Rinse and wipe off the probe quickly and place it in the calorimeter, where it will now indicate the temperature of the distilled water. Stir with the temperature probe until the temperature becomes essentially constant, and record the temperature. Note: Although you will be able to determine the initial temperatures of those liquids from the plot you will print out, you should also record these values on the report sheet at the end Experiment 9 9-5

6 of the handout, since the values obtained from the MeasureNet workstation screen are more precise. e. Quickly transfer the NH 4Cl into the distilled water in the calorimeter and stir. Continue until the temperature becomes essentially constant. Record the temperature. f. Quickly transfer the NaOH solution into the calorimeter and stir. Continue until the temperature becomes essentially constant. Record the temperature. g. Press START/STOP to stop collecting data (or wait until it stops automatically at 300 seconds) and use FILE OPTIONS to print out copies of your data. Label this plot for later analysis, indicating what is being measured in each portion of the plot and what has been added to the calorimeter. h. Pour the calorimeter contents down the drain, then rinse and dry all equipment. A.2. SOLID LAST Path a. d. These are exactly the same as in the SOLID FIRST Path. e. Quickly add the NaOH solution to the water already in the calorimeter and stir. Continue until the temperature becomes essentially constant, and then record the temperature. f. Quickly transfer the NH 4Cl into the solution in the calorimeter and stir. Continue until the temperature becomes essentially constant, and then record the temperature.. g. h. Same as in the SOLID FIRST Path. B. Enthalpy Changes NaOH and HCl Reaction In this part of the experiment you will compare two different pathways for carrying out the following process: NaOH(s, 2.00 g) + H 2O(l, 50 ml) + HCl(aq, 1.00M, 50 ml) H 2O (l) + NaCl(aq) (9-7) Notice again that, as in Part B, the amounts have been chosen so that mol each of NaOH and HCl will react to form mol each of H 2O and NaCl. In the first pathway (SOLID FIRST), you will first dissolve the NaOH in the water, recording the resulting temperature, and then add the HCl solution to the NaOH solution, again recording the resulting temperature. In the second pathway, you will reverse the order (SOLID LAST). As in Part A, both pathways have the same starting and ending points, so this experiment will also provide data for a test of the validity of Hess s Law. B.1. SOLID FIRST Path a. Set up the calorimeter by nesting two Styrofoam cups together. Obtain ~100 ml of HCl solution in a clean beaker. b. Use separate graduated cylinders to measure 50.0 ml of distilled water and 50.0 ml of 1.0 M HCl. Pour the distilled water into the calorimeter. c. Carefully weigh out as close to 2.000g of NaOH as possible, (within g) using the top-loading balance. d. Press START/STOP to begin collecting data. Place the temperature probe in the solution in the graduated cylinder containing HCl solution and begin stirring until the temperature reading is fairly steady. Record its temperature. Rinse and wipe off the probe quickly and place Experiment 9 9-6

7 it in the calorimeter, where it will now indicate the temperature of the distilled water. Stir with the temperature probe until the temperature becomes essentially constant and record the temperature. e. Quickly transfer the NaOH into the distilled water in the calorimeter and stir. Continue until the temperature becomes essentially constant. Record the temperature. f. Quickly transfer the HCl solution into the calorimeter and stir. Continue until the temperature becomes essentially constant. Record the temperature. g. Press START/STOP to stop collecting data (or wait until it stops automatically at 300 seconds) and use FILE OPTIONS to print out copies of your data. Label this plot for later analysis, indicating what is being measured in each portion of the plot and what has been added to the calorimeter. h. Pour the calorimeter contents down the drain, then rinse and dry all equipment. B.2. SOLID LAST Path a. d. These are exactly the same as in the SOLID FIRST Path. e. Quickly add the HCl solution to the water already in the calorimeter and stir. Continue until the temperature becomes essentially constant. f. Quickly transfer the NaOH into the solution in the calorimeter and stir. Continue until the temperature becomes essentially constant. g. h. Same as in the SOLID FIRST Path. Waste disposal Combine any leftover NaOH and HCl solutions and pour down the sink. Experiment 9 9-7

8 RESULTS A. Enthalpy Changes NH4Cl and NaOH Reaction Use your printed graphs for the SOLID FIRST and SOLID LAST pathways for this overall process to determine the enthalpy change for each step you carried out. In each case you need C and T, which are combined in EQUATION 9-4 to give q, the amount of heat released or absorbed in the step. EQUATION 9-5 then gives the enthalpy change, H. Estimate the heat capacity C as described in the TECHNIQUE section. Thus, for example, the heat capacity for the first step is 50.0 ml g/ml J/( C g) = J/ C. Use this value and your measured value for T to calculate H for this step. Using FIGURE 9-1 as an example, T for the first step is T 3 T 2 = 3.75 C. Therefore H = q = ( 3.75 C J/ C) = +785 J. Carry out the analogous calculation to find H for the second step. Be careful here, since the initial temperatures of the two solutions you are mixing are not the same. It is useful to imagine even this single step as occurring in two simpler steps. First imagine the two liquids in thermal contact, that is, able to transfer heat, but not to actually mix and react. Heat would flow from the warmer solution to the cooler solution until they were at the same temperature. Since the heat capacities of the two solutions are nearly the same, this final temperature would be the average of the two. (That is, it would be the average of the initial temperature of the NaOH solution and the initial temperature of the NH 4Cl solution, which, of course, is the final temperature of the first step). From FIGURE 9-1, this average is (T 1 + T 3) / 2 = (23.51 C C) / 2 = C. The change in temperature caused by the actual reaction occurring upon mixing is the change from this average temperature to the final temperature after mixing, T 4 in FIGURE 9-1. Therefore T = C C = C. To calculate H for the second step, remember that the amount of water present is doubled from what it was in the first step, since we treat the solution added as though it were just water. Calculate the new heat capacity and use your temperature data to find H for the second step. In this example, H = 0.49 C J/ C = 205 J. Analyze your results for both pathways and enter them in the data sheets provided. B. Enthalpy Changes NaOH and HCl Reaction Treat your data from this part of the experiment in exactly the same manner you treated the data in Part B. Use the measured temperature changes to determine the enthalpy changes for the individual steps, and enter your results in the data sheets provided. C. Test of Hess s Law Transfer the enthalpy changes for the individual steps from your results in Parts B and C to the blanks provided in the data sheets for Part D. Use Hess s Law of Constant Heat Summation (see the INTRODUCTION) to calculate the overall H for each of the two pathways for each of the two overall processes studied. Calculate the difference between the two overall H values in each case and enter it into the data sheet. The size of this difference depends mainly on two things: the validity of Hess s Law, and the quality of your experimental technique. If Hess s Law is valid, the value should be zero, within experimental error. Experiment 9 9-8

9 EXPERIMENT 9 REPORT SHEET Name: Date: A. ENTHALPY CHANGES NH4Cl AND NaOH REACTION SOLID FIRST Pathway SOLID LAST Pathway Mass of NH4Cl Initial temperature (NaOH(aq)) Initial temperature (water) FIRST STEP: Initial temperature (water) (average) Final temperature Temperature change Heat capacity q Enthalpy change SECOND STEP: Initial temperature (average) (diluted solution) Final temperature Temperature change Heat capacity q Enthalpy change Experiment 9 9-9

10 B. ENTHALPY CHANGES NaOH AND HCl REACTION SOLID FIRST Pathway SOLID LAST Pathway Mass of NaOH Initial temperature (HCl(aq)) Initial temperature (water) FIRST STEP: Initial temperature (water) (average) Final temperature Temperature change Heat capacity q Enthalpy change SECOND STEP: Initial temperature (average) (diluted solution) Final temperature Temperature change Heat capacity q Enthalpy change Experiment

11 EXPERIMENT 9 REPORT SHEET (CONT.) Name: Date: C. TEST OF HESS S LAW NH4Cl + NaOH Reaction: SOLID FIRST Pathway SOLID LAST Pathway H for first step H for second step Overall H Difference between the two overall H values NaOH + HCl Reaction: SOLID FIRST Pathway SOLID LAST Pathway H for first step H for second step Overall H Difference between the two overall H values Experiment

12 Notes for Experiment 9 Procedure considerations and helpful hints: 1M HCl and 1M NaOH are caustic materials! Wear your goggles! Avoid spilling. If you spill some on your clothes or skin, rinse with water as soon as possible. If you spill a large amount on the floor or benchtop, notify your TA. Solid NaOH is very caustic! Do not let it come into contact with your skin! Clean up any NaOH spills around the balance area! The calculations in this experiment are challenging! You should perform the calculations for at least one pathway before you leave so that your TA can help make sure that you are doing them correctly. In order to answer one of the Discussion questions, you will need to look up the heat of solution values for NaOH and NH4Cl. These values can be found in the CRC handbook in your lab room. Note the units for these values given at the top of the table. Alternatively, you can look them up online; one good source is 11/10 Experiment

Chemistry CP Lab: Additivity of Heats of Reaction (Hess Law)

Chemistry CP Lab: Additivity of Heats of Reaction (Hess Law) Chemistry CP Lab: Additivity of Heats of Reaction (Hess Law) Name: Date: The formation or destruction of chemical bonds is always accompanied by an energy exchange between the reactant molecules and the

More information

8 Enthalpy of Reaction

8 Enthalpy of Reaction E x p e r i m e n t Enthalpy of Reaction Lecture and Lab Skills Emphasized Calculating the heat and enthalpy of reactions. Writing net ionic equations. Using Hess s law to determine the enthalpy of a reaction.

More information

Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7

Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7 Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7 1. Is the sign of Δ r H for an exothermic reaction positive or negative? Why? 2. When 4.21 grams of potassium hydroxide are added to 250.

More information

Experiment #12. Enthalpy of Neutralization

Experiment #12. Enthalpy of Neutralization Experiment #12. Enthalpy of Neutralization Introduction In the course of most physical processes and chemical reactions there is a change in energy. In chemistry what is normally measured is ΔH (enthalpy

More information

DETERMINING AND USING H

DETERMINING AND USING H DETERMINING AND USING H INTRODUCTION CHANGES IN CHEMISTRY Chemistry is the science that studies matter and the changes it undergoes. Changes are divided into two categories: physical and chemical. During

More information

To use calorimetry results to calculate the specific heat of an unknown metal. To determine heat of reaction ( H) from calorimetry measurements.

To use calorimetry results to calculate the specific heat of an unknown metal. To determine heat of reaction ( H) from calorimetry measurements. Calorimetry PURPOSE To determine if a Styrofoam cup calorimeter provides adequate insulation for heat transfer measurements, to identify an unknown metal by means of its heat capacity and to determine

More information

The Enthalpies of Reactions

The Enthalpies of Reactions The Enthalpies of Reactions Collect 2 Styrofoam cups & a cup lid Digital thermometer Stop watch (from TA) Prepare 400 ml beaker 50 ml graduated cylinder * Take the warm water heated in hood (2015/09/20

More information

EXPERIMENT A8: CALORIMETRY. Learning Outcomes. Introduction. Upon completion of this lab, the student will be able to:

EXPERIMENT A8: CALORIMETRY. Learning Outcomes. Introduction. Upon completion of this lab, the student will be able to: 1 EXPERIMENT A8: CALORIMETRY Learning Outcomes Upon completion of this lab, the student will be able to: 1) Measure the heat of a reaction under constant pressure conditions. 2) Calculate the enthalpy

More information

Chemistry 3202 Lab 6 Hess s Law 1

Chemistry 3202 Lab 6 Hess s Law 1 Chemistry 3202 Lab 6 Hess s Law 1 Lab 6 Hess's Law Introduction Chemical and physical changes are always accompanied by a change in energy. Energy changes may be observed by detecting heat flow between

More information

Experiment #13. Enthalpy of Hydration of Sodium Acetate.

Experiment #13. Enthalpy of Hydration of Sodium Acetate. Experiment #13 Enthalpy of Hydration of Sodium Acetate Goal To determine the enthalpy (ΔH) for the following process: NaC 2 H 3 O 2 (s) + 3 H 2 O(l) à NaC 2 H 3 O 2 3H 2 O(s) Introduction Most chemical

More information

Additivity of Heats of Reaction: Hess s Law

Additivity of Heats of Reaction: Hess s Law Additivity of Heats of Reaction: Hess s Law Experiment In this experiment, you will use a Styrofoam-cup calorimeter to measure the heat released by three reactions. One of the reactions is the same as

More information

Lab 5 Enthalpy of Solution Formation

Lab 5 Enthalpy of Solution Formation Chemistry 3202 Lab 5 Enthalpy of Solution Formation Page 1 of 9 Lab 5 Enthalpy of Solution Formation Introduction This lab activity will introduce you to the measurement of energy change associated with

More information

Determining the Enthalpy of a Chemical Reaction

Determining the Enthalpy of a Chemical Reaction Determining the Enthalpy of a Chemical Reaction Computer 13 All chemical reactions involve an exchange of heat energy; therefore, it is tempting to plan to follow a reaction by measuring the enthalpy change

More information

HESS S LAW: ADDITIVITY OF HEATS OF REACTION

HESS S LAW: ADDITIVITY OF HEATS OF REACTION HESS S LAW: ADDITIVITY OF HEATS OF REACTION From Chemistry with Calculators, Vernier Software & Technology In this experiment, you will use a Styrofoam-cup calorimeter to measure the heat released by three

More information

HESS S LAW: ADDITIVITY OF HEATS OF REACTION

HESS S LAW: ADDITIVITY OF HEATS OF REACTION HESS S LAW: ADDITIVITY OF HEATS OF REACTION LAB THC 1.COMP From Chemistry with Computers, Vernier Software & Technology, 2000 INTRODUCTION In this experiment, you will use a Styrofoam-cup calorimeter to

More information

Thermodynamics Enthalpy of Reaction and Hess s Law

Thermodynamics Enthalpy of Reaction and Hess s Law P.O. Box 219 Batavia, Illinois 60510 1-800-452-1261 flinn@flinnsci.com Visit our website at: www.flinnsci.com 2003 Flinn Scientific, Inc. All Rights Reserved. Your Safer Source for Science Supplies Thermodynamics

More information

C q T q C T. Heat is absorbed by the system H > 0 endothermic Heat is released by the system H < 0 exothermic

C q T q C T. Heat is absorbed by the system H > 0 endothermic Heat is released by the system H < 0 exothermic PLEASE REORD ALL DATA DIRETLY INTO YOUR LAB NOTEBOOKS Introduction Heating a substance is one of the simplest processes carried out in the chemical laboratory, and is usually accompanied by a rise in the

More information

Name: Chemistry 103 Laboratory University of Massachusetts Boston HEATS OF REACTION PRELAB ASSIGNMENT

Name: Chemistry 103 Laboratory University of Massachusetts Boston HEATS OF REACTION PRELAB ASSIGNMENT Name: Chemistry 103 Laboratory University of Massachusetts Boston HEATS OF REACTION PRELAB ASSIGNMENT Chemical and physical changes usually involve the absorption or liberation of heat, given the symbol

More information

Reaction Stoichiometry

Reaction Stoichiometry Reaction Stoichiometry PURPOSE To determine the stoichiometry of acid-base reactions by measuring temperature changes which accompany them. GOALS To learn to use the MicroLab Interface. To practice generating

More information

COPYRIGHT FOUNTAINHEAD PRESS

COPYRIGHT FOUNTAINHEAD PRESS Calorimetry: Heats of Solution Objective: Use calorimetric measurements to determine heats of solution of two ionic compounds. Materials: Solid ammonium nitrate (NH 4 NO 3 ) and anhydrous calcium chloride

More information

CALORIMETRY. m = mass (in grams) of the solution C p = heat capacity (in J/g- C) at constant pressure T = change in temperature in degrees Celsius

CALORIMETRY. m = mass (in grams) of the solution C p = heat capacity (in J/g- C) at constant pressure T = change in temperature in degrees Celsius CALORIMETRY INTRODUCTION The heat evolved by a chemical reaction can be determined using a calorimeter. The transfer of heat or flow of heat is expressed as the change in Enthalpy of a reaction, H, at

More information

Solution Calorimetry

Solution Calorimetry Experiment 7 Solution Calorimetry Prepared by Stephen E. Schullery and Ross S. Nord, Eastern Michigan University PURPOSE Measure the heats of two simple reactions and use Hess's Law to theoretically predict

More information

6 Acid Base Titration

6 Acid Base Titration E x p e r i m e n t Acid Base Titration Experiment : http://genchemlab.wordpress.com/-titration/ objectives To understand the concept of titration. To explain the difference between the analyte and standard

More information

Experiment 14 - Heats of Reactions

Experiment 14 - Heats of Reactions Experiment 14 - Heats of Reactions If a chemical reaction is carried out inside a calorimeter, the heat evolved or absorbed by the reaction can be determined. A calorimeter is an insulated container, and

More information

Additivity of Heats of Reaction: Hess s Law

Additivity of Heats of Reaction: Hess s Law Additivity of Heats of Reaction: Hess s Law Experiment 21 In this experiment, you will use a Styrofoam-cup calorimeter to measure the heat released by three reactions. One of the reactions is the same

More information

MOST of the reactions are carried out at atmospheric pressure, hence

MOST of the reactions are carried out at atmospheric pressure, hence MOST of the reactions are carried out at atmospheric pressure, hence heat changes noted for these reactions are enthalpy changes. Enthalpy changes are directly related to the temperature changes by the

More information

CHM201 General Chemistry and Laboratory I Laboratory 7 Thermochemistry and Hess s Law May 2, 2018

CHM201 General Chemistry and Laboratory I Laboratory 7 Thermochemistry and Hess s Law May 2, 2018 Purpose: CHM201 General Chemistry and Laboratory I Laboratory 7 Thermochemistry and Hess s Law May 2, 2018 In this laboratory, you will measure heat changes arising from chemical reactions. You will use

More information

experiment7 Explaining the difference between analyte and standard solutions. Know the definition of equivalence point.

experiment7 Explaining the difference between analyte and standard solutions. Know the definition of equivalence point. 93 experiment7 Determining an Unknown Concentration Understanding the concept of titration. LECTURE AND LAB SKILLS EMPHASIZED Explaining the difference between analyte and standard solutions. Know the

More information

HEATS OF REACTION EXPERIMENT

HEATS OF REACTION EXPERIMENT 16 Text Reference Section 11.4 HEATS OF REACTION EXPERIMENT PURPOSE To measure the heats of reaction for three related exothermic reactions and to verify Hess s law of heat summation. Time Required 50

More information

Experiment 12 Determination of an Enthalpy of Reaction, Using Hess s Law

Experiment 12 Determination of an Enthalpy of Reaction, Using Hess s Law Experiment 12 Determination of an Enthalpy of Reaction, Using Hess s Law Object: To measure the standard heat of formation, f, of MgO (s), and to become familiar with calorimetry as a toll for measuring

More information

Thermodynamics. Equations to use for the calculations:

Thermodynamics. Equations to use for the calculations: Thermodynamics Introduction: Gibbs Free Energy, G, can be used to determine if a reaction is spontaneous or not. A negative value of G indicates that a given reaction is spontaneous at the measured conditions

More information

not to be republished NCERT MOST of the reactions are carried out at atmospheric pressure, hence THERMOCHEMICAL MEASUREMENT UNIT-3

not to be republished NCERT MOST of the reactions are carried out at atmospheric pressure, hence THERMOCHEMICAL MEASUREMENT UNIT-3 UNIT-3 THERMOCHEMICAL MEASUREMENT MOST of the reactions are carried out at atmospheric pressure, hence heat changes noted for these reactions are enthalpy changes. Enthalpy changes are directly related

More information

AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) Figure 1

AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) Figure 1 www.pedersenscience.com AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) 5.A.2: The process of kinetic energy transfer at the particulate scale is referred to in this course as heat transfer,

More information

Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world

Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: www.pearsoned.co.uk Pearson Education Limited 2014

More information

AP Chemistry: Designing an Effective Hand Warmer Student Guide INTRODUCTION

AP Chemistry: Designing an Effective Hand Warmer Student Guide INTRODUCTION AP Chemistry: Designing an Effective Hand Warmer Student Guide INTRODUCTION AP and the Advanced Placement Program are registered trademarks of the College Entrance Examination Board. The activity and materials

More information

Thermodynamics. Equations to use for the calculations:

Thermodynamics. Equations to use for the calculations: Thermodynamics Introduction: Gibbs Free Energy, G, can be used to determine if a reaction is spontaneous or not. A negative value of G indicates that a given reaction is spontaneous at the measured conditions

More information

Thermochemistry: Calorimetry and Hess s Law

Thermochemistry: Calorimetry and Hess s Law Thermochemistry: Calorimetry and Hess s Law Some chemical reactions are endothermic and proceed with absorption of heat while others are exothermic and proceed with an evolution of heat. The magnitude

More information

Experiment 5. Heat and Temperature

Experiment 5. Heat and Temperature Experiment 5 Heat and Temperature This coffee isn t hot enough! E5-1 E5-2 The Task In this experiment you will study the heat flow associated with a range of processes and examine the relationship between

More information

CHM112 Lab Hydrolysis and Buffers Grading Rubric

CHM112 Lab Hydrolysis and Buffers Grading Rubric Name Team Name CHM112 Lab Hydrolysis and Buffers Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial calculations completed

More information

Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law

Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law EXPERIMENT 9 Prepared by Edward L. Brown, Lee University and Verrill M. Norwood, Cleveland State Community College To become

More information

Endothermic and Exothermic Reactions

Endothermic and Exothermic Reactions Endothermic and Exothermic Reactions Experiment 1 Many chemical reactions give off energy. Chemical reactions that release energy are called exothermic reactions. Some chemical reactions absorb energy

More information

THER Mo CHEMISTRY: HEAT OF Ne UTRALIZATION

THER Mo CHEMISTRY: HEAT OF Ne UTRALIZATION Experiment 11 Name: 42 THER Mo CHEMISTRY: HEAT OF Ne UTRALIZATION In this experiment, you will use calorimetry to experimentally determine the heat of neutralization of NaOH-HCl, or the enthalpy of the

More information

Just a reminder that everything you do related to lab should be entered directly into your lab notebook. Calorimetry

Just a reminder that everything you do related to lab should be entered directly into your lab notebook. Calorimetry Just a reminder that everything you do related to lab should be entered directly into your lab notebook. Objectives: Calorimetry After completing this lab, you should be able to: - Assemble items of common

More information

Measuring Enthalpy Changes

Measuring Enthalpy Changes Measuring Enthalpy Changes PURPOSE To observe changes in enthalpy in chemical processes. GOALS To identify exothermic and endothermic processes. To relate enthalpy changes and entropy changes to changes

More information

If you need to reverse a reaction, the enthalpy is negated:

If you need to reverse a reaction, the enthalpy is negated: In the previous experiment you explored the heat of solution of potassium hydroxide. Using Hess s law, you will now use those results in conjunction with the data collected in this experiment to determine

More information

Solution Calorimetry

Solution Calorimetry Experiment 7 Solution Calorimetry Prepared by Stephen E. Schullery and Ross S. Nord, Eastern Michigan University PURPOSE Measure the heats of two simple reactions and use Hess's Law to theoretically predict

More information

Enthalpy of Formation of Ammonium Chloride Version 6.2.5

Enthalpy of Formation of Ammonium Chloride Version 6.2.5 Enthalpy of Formation of Ammonium Chloride Version 6.2.5 Michael J. Vitarelli Jr. Department of Chemistry and Chemical Biology Rutgers University, 60 Taylor Road, Piscataway, NJ 08854 I. INTRODUCTION Enthalpy

More information

Rate Law Determination of the Crystal Violet Reaction. Evaluation copy

Rate Law Determination of the Crystal Violet Reaction. Evaluation copy Rate Law Determination of the Crystal Violet Reaction Computer 30 In this experiment, you will observe the reaction between crystal violet and sodium hydroxide. One objective is to study the relationship

More information

Chemistry 212 THE ENTHALPY OF FORMATION OF MAGNESIUM OXIDE LEARNING OBJECTIVES

Chemistry 212 THE ENTHALPY OF FORMATION OF MAGNESIUM OXIDE LEARNING OBJECTIVES Chemistry 212 THE ENTHALPY OF FORMATION OF MAGNESIUM OXIDE The learning objectives of this experiment are LEARNING OBJECTIVES A simple coffee cup calorimeter will be used to determine the enthalpy of formation

More information

Apply the ideal gas law (PV = nrt) to experimentally determine the number of moles of carbon dioxide gas generated

Apply the ideal gas law (PV = nrt) to experimentally determine the number of moles of carbon dioxide gas generated Teacher Information Ideal Gas Law Objectives Determine the number of moles of carbon dioxide gas generated during a reaction between hydrochloric acid and sodium bicarbonate. Through this investigation,

More information

Experiment 2: Reaction Stoichiometry by Thermometric Titration

Experiment 2: Reaction Stoichiometry by Thermometric Titration Experiment 2: Reaction Stoichiometry by Thermometric Titration Introduction The net result of a reaction (a chemical change) is summarized by a chemical equation. In order to write a chemical equation,

More information

Saturday Study Session 1 3 rd Class Student Handout Thermochemistry

Saturday Study Session 1 3 rd Class Student Handout Thermochemistry Saturday Study Session 1 3 rd Class Student Handout Thermochemistry Multiple Choice Identify the choice that best completes the statement or answers the question. 1. C 2 H 4 (g) + 3 O 2 (g) 2 CO 2 (g)

More information

In general, the condition for a process to occur (for it to be "spontaneous") is that G < 0 (i.e. negative) where

In general, the condition for a process to occur (for it to be spontaneous) is that G < 0 (i.e. negative) where EXPERIMENT 9 Enthalpy Measurement in Chemical Reactions INTRODUCTION: Chemical and physical changes are often accompanied by heat evolution or absorption. A process in which heat is released to the surroundings

More information

The CCLI Initiative Computers in Chemistry Laboratory Instruction

The CCLI Initiative Computers in Chemistry Laboratory Instruction Experiment Determining the Coordination Number of Ni and Cu The CCLI Initiative Computers in Chemistry Laboratory Instruction by Enthalpy The objectives of this experiment are to... LEARNING OBJECTIVES

More information

Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law

Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law Calorimetry Measurements of Fusion, Hydration and Neutralization - Hess Law EXPERIMENT 7 Prepared by Edward L. Brown, Lee University To become familiar with energy changes and the use of a calorimeter

More information

Chemistry 1B Experiment 11 49

Chemistry 1B Experiment 11 49 Chemistry 1B Experiment 11 49 11 Buffer Solutions Introduction Any solution that contains both a weak acid HA and its conjugate base A in significant amounts is a buffer solution. A buffer is a solution

More information

ENTHALPY OF FORMATION OF MgO

ENTHALPY OF FORMATION OF MgO ENTHALPY OF FORMATION OF MgO ELECTRONIC LABORATORY NOTEBOOK (ELN) INSTRUCTIONS All work for this experiment must be recorded, attached, or answered in the ELN. Create a pre & inlab page in the Experiment

More information

IB Chemistry Solutions Gasses and Energy

IB Chemistry Solutions Gasses and Energy Solutions A solution is a homogeneous mixture it looks like one substance. An aqueous solution will be a clear mixture with only one visible phase. Be careful with the definitions of clear and colourless.

More information

Calorimetric Determination of Reaction Enthalpies

Calorimetric Determination of Reaction Enthalpies H + (aq) + OH - q H 2 O Calorimetric Determination of Reaction Enthalpies Purpose: Determine the enthalpy of dissociation of CH 3 COOH CH 3 COOH (aq) CH 3 COO - (aq) + H + (aq) Techniques: Calorimetry

More information

Solvation and Freezing Point Depression

Solvation and Freezing Point Depression Experiment 4 Solvation and Freezing Point Depression Prepared by Ross S. Nord, Eastern Michigan University PURPOSE To investigate the solvation process, measure freezing-point depression, and determine

More information

Experiment 15 - Heat of Fusion and Heat of Solution

Experiment 15 - Heat of Fusion and Heat of Solution Experiment 15 - Heat of Fusion and Heat of Solution Phase changes and dissolving are physical processes that involve heat. In this experiment, you will determine the heat of fusion of ice (the energy required

More information

Thermochemistry: the study of energy (in the from of heat) changes that accompany physical & chemical changes

Thermochemistry: the study of energy (in the from of heat) changes that accompany physical & chemical changes Thermochemistry Thermochemistry: the study of energy (in the from of heat) changes that accompany physical & chemical changes heat flows from high to low (hot cool) endothermic reactions: absorb energy

More information

Experiment 6 Heat of Neutralization

Experiment 6 Heat of Neutralization CHEM 102 GENERAL CHEMISTRY Experiment 6 Heat of Neutralization Purpose: To calculate enthalpy change of a reaction by using calorimeter and understand the difference between endothermic and exothermic

More information

Hess' Law: Calorimetry

Hess' Law: Calorimetry Exercise 9 Page 1 Illinois Central College CHEMISTRY 130 Name: Hess' Law: Calorimetry Objectives The objectives of this experiment are to... - measure the heats of reaction for two chemical reactions.

More information

c H2 O = J (g H 2 O)( C change)

c H2 O = J (g H 2 O)( C change) Calorimetry 1 CHM120 Introduction: Have you ever noticed the nutrition label located on the packaging of the food you buy? One of the first things listed on the label are the calories per serving. How

More information

How bad is that snack anyway?

How bad is that snack anyway? Physical Sciences 11 Experiment 1 How bad is that snack anyway? Monday, 2/10 Wednesday, 2/12 Science Center Room 117 Please read this entire document and complete the attached prelab before your lab. This

More information

Lab #9- Calorimetry/Thermochemistry to the Rescue

Lab #9- Calorimetry/Thermochemistry to the Rescue Chesapeake Campus Chemistry 111 Laboratory Lab #9- Calorimetry/Thermochemistry to the Rescue Objectives Determine whether a reaction is endothermic or exothermic. Determine the best ionic compound of to

More information

RATE LAW DETERMINATION OF CRYSTAL VIOLET HYDROXYLATION

RATE LAW DETERMINATION OF CRYSTAL VIOLET HYDROXYLATION Rate Law Determination of Crystal Violet Hydroxylation Revised 5/22/12 RATE LAW DETERMINATION OF CRYSTAL VIOLET HYDROXYLATION Adapted from "Chemistry with Computers" Vernier Software, Portland OR, 1997

More information

Energy and Energy Conversion Minneapolis Community and Tech. College Principles of Chemistry 1 v q water = m water C water T water (Equation 1)

Energy and Energy Conversion Minneapolis Community and Tech. College Principles of Chemistry 1 v q water = m water C water T water (Equation 1) Energy and Energy Conversion Minneapolis Community and Tech. College Principles of Chemistry 1 v.6.13 Energy Energy is defined by most textbooks as the capacity to do work. However, the true usefulness

More information

Exp 09: Heat of Reaction

Exp 09: Heat of Reaction Your job is to use a calorimeter to determine the heat of reaction for three different chemical reactions. Each of these reactions is an acid-base neutralization reaction. Before using your calorimeter

More information

CHEMISTRY 130 General Chemistry I. Thermochemistry

CHEMISTRY 130 General Chemistry I. Thermochemistry CHEMISTRY 130 General Chemistry I Thermochemistry The burning of a match, shown above [1], is a chemical reaction between oxygen and sulfur. [2] Intuitively, we know that this reaction releases heat enough

More information

Table 1. Data for Heat Capacity Trial 1 Trial 2

Table 1. Data for Heat Capacity Trial 1 Trial 2 Thermochemistry: Measuring Enthalpy Change in Chemical Reactions Experiment created by the UMaine InterChemNet Team. Adapted with permission. Print this form and bring it with you to lab. You will complete

More information

Measuring Enthalpy Changes and Gas Laws

Measuring Enthalpy Changes and Gas Laws Measuring Enthalpy Changes and Gas Laws PURPOSE A B To observe changes in enthalpy in chemical processes. To determine the relationship between the pressure and volume of a gas. GOALS To identify exothermic

More information

#30 Thermochemistry: Heat of Solution

#30 Thermochemistry: Heat of Solution #30 Thermochemistry: Heat of Solution Purpose: You will mix different salts with water and note any change in temperature. Measurements using beakers will be compared to measurements using polystyrene

More information

Energy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy

Energy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy THERMOCHEMISTRY Thermodynamics Study of energy and its interconversions Energy is TRANSFORMED in a chemical reaction (POTENTIAL to KINETIC) HEAT (energy transfer) is also usually produced or absorbed -SYSTEM:

More information

The Hand Warmer Design Challenge: Where Does the Heat Come From?

The Hand Warmer Design Challenge: Where Does the Heat Come From? The Hand Warmer Design Challenge: Where Does the Heat Come From? LSNED Learn Something New Every Day About Sharing and Contributions Interesting Facts Science In Your Mittens: The Chemistry Of Hand Warmers

More information

Thermochemistry. Introduction. Pre-lab. Safety

Thermochemistry. Introduction. Pre-lab. Safety Introduction Thermochemistry All chemical reactions and phase changes involve energy. One form of energy is heat: when a change in the energy of a system results in a temperature difference, we say that

More information

Heat. Heat Terminology 04/12/2017. System Definitions. System Definitions

Heat. Heat Terminology 04/12/2017. System Definitions. System Definitions System Definitions Heat Physical Science 20 Ms. Hayduk Heat Terminology System: the part of the universe being studied (big Earth, or small one atom) Surroundings: the part of the universe outside the

More information

Determining the K sp of Calcium Hydroxide

Determining the K sp of Calcium Hydroxide Determining the K sp of Calcium Hydroxide (Titration Method) Computer 23 Calcium hydroxide is an ionic solid that is sparingly soluble in water. A saturated, aqueous, solution of Ca(OH) 2 is represented

More information

Density of Aqueous Sodium Chloride Solutions

Density of Aqueous Sodium Chloride Solutions Experiment 3 Density of Aqueous Sodium Chloride Solutions Prepared by Ross S. Nord and Stephen E. Schullery, Eastern Michigan University PURPOSE Determine the concentration of an unknown sodium chloride

More information

Experiment 2 Heat of Combustion: Magnesium

Experiment 2 Heat of Combustion: Magnesium Experiment 2 Heat of Combustion: Magnesium Purpose Hess s Law states that when are going from a particular set of reactants to a particular set of products, the heat of reaction is the same whether the

More information

CHAPTER 6: Chemical Energetics

CHAPTER 6: Chemical Energetics CHAPTER 6: Chemical Energetics 6.1 Enthalpy Changes 6.2 Standard Enthalpy Changes 6.3 Hess' Law 6.4 Bond Energy Learning outcomes: (a) explain that some chemical reactions are accompanied by energy changes,

More information

Experiment 6: Using Calorimetry to Determine the Enthalpy of Formation of Magnesium Oxide

Experiment 6: Using Calorimetry to Determine the Enthalpy of Formation of Magnesium Oxide Experiment 6: Using Calorimetry to Determine the Enthalpy of Formation of Magnesium Oxide Reading: Chapter sections 5.4 5.7 of your textbook and this lab handout. Ongoing Learning Goals: To use a scientific

More information

ADDITIONAL RESOURCES. Duration of resource: 21 Minutes. Year of Production: Stock code: VEA12052

ADDITIONAL RESOURCES. Duration of resource: 21 Minutes. Year of Production: Stock code: VEA12052 ADDITIONAL RESOURCES Chemical changes occur around us, and inside us, all the time. When chemical reactions happen, one or more new substances are formed and energy is either given off or absorbed in the

More information

Modification of Procedure for Experiments 17 and 18. everything with distilled water and dry thoroughly. (Note: Do not use acetone to rinse cups.

Modification of Procedure for Experiments 17 and 18. everything with distilled water and dry thoroughly. (Note: Do not use acetone to rinse cups. Modification of Procedure for Experiments 17 and 18 I. Calorimeter Constant Obtain two polystyrene cups, a lid for one of the cups and a magnetic stirrer. Rinse everything with distilled water and dry

More information

EXPERIMENT 15. USING CONDUCTIVITY TO LOOK AT SOLUTIONS: DO WE HAVE CHARGED IONS OR NEUTRAL MOLECULES? rev 7/09

EXPERIMENT 15. USING CONDUCTIVITY TO LOOK AT SOLUTIONS: DO WE HAVE CHARGED IONS OR NEUTRAL MOLECULES? rev 7/09 EXPERIMENT 15 USING CONDUCTIVITY TO LOOK AT SOLUTIONS: DO WE AVE CARGED IONS OR NEUTRAL MOLECULES? rev 7/09 GOAL After you complete this experiment, you should have a better understanding of aqueous solutions

More information

CALORIMETRY: Heat of Fusion of Ice

CALORIMETRY: Heat of Fusion of Ice Pre-Lab Discussion CALORIMETRY: Heat of Fusion of Ice When a chemical or physical change takes place, heat is either given off or absorbed That is, the change is either exothermic or endothermic It is

More information

Eye on Ions: Electrical Conductivity of Aqueous Solutions

Eye on Ions: Electrical Conductivity of Aqueous Solutions Eye on Ions: Electrical Conductivity of Aqueous Solutions Pre-lab Assignment: Reading: 1. Chapter sections 4.1, 4.3, 4.5 and 4.6 in your course text. 2. This lab handout. Questions: 1. Using table 1 in

More information

CHEMISTRY 30 Assessment Enthalpy Change and Calorimetry Formative

CHEMISTRY 30 Assessment Enthalpy Change and Calorimetry Formative CHEMISTRY 30 Assessment Enthalpy Change and Calorimetry Formative Record all responses in this book. Keep this question book and the answer key as part of your notes. 1. Open and closed systems can be

More information

Chem 2115 Experiment #7. Volumetric Analysis & Consumer Chemistry Standardization of an unknown solution, analysis of vinegar & antacid tablets

Chem 2115 Experiment #7. Volumetric Analysis & Consumer Chemistry Standardization of an unknown solution, analysis of vinegar & antacid tablets Chem 2115 Experiment #7 Volumetric Analysis & Consumer Chemistry Standardization of an unknown solution, analysis of vinegar & antacid tablets OBJECTIVE: The goals of this experiment are to learn titration

More information

Calorimetry and Hess s Law Prelab

Calorimetry and Hess s Law Prelab Calorimetry and Hess s Law Prelab Name Total /10 1. What is the purpose of this experiment? 2. Make a graph (using some kind of graphing computer software) of temperature vs. time for the following data:

More information

Pre-lab: Read section 9.9 (pages ) on acid-base titrations in the textbook. Complete the attached pre-lab by Tuesday, June 2.

Pre-lab: Read section 9.9 (pages ) on acid-base titrations in the textbook. Complete the attached pre-lab by Tuesday, June 2. Chemistry 121 Lab 5: Titration of an unknown acid Objective: Determine the concentration of an unknown monoprotic acid by titration, the process that matches the number of moles of base with the number

More information

Acid-Base Titration. Volume NaOH (ml) Figure 1

Acid-Base Titration. Volume NaOH (ml) Figure 1 LabQuest 24 A titration is a process used to determine the volume of a solution needed to react with a given amount of another substance. In this experiment, you will titrate hydrochloric acid solution,

More information

Investigation 12. The Hand Warmer Design Challenge: Where does the Heat come from?

Investigation 12. The Hand Warmer Design Challenge: Where does the Heat come from? Investigation 12 The Hand Warmer Design Challenge: Where does the Heat come from? Safety Solids are eye and skin irritants. CaCl 2 can cause skin burns. Wear googles at all times. Failure to do so will

More information

Thermodynamics of Salt Dissolution

Thermodynamics of Salt Dissolution 1 Thermodynamics of Salt Dissolution ORGANIZATION Mode: Part A groups of 3 or 4; Part B individual work; Part C back to groups Grading: lab notes, lab performance, and post-lab report Safety: goggles,

More information

Experiment 17 It s A Gas and More!

Experiment 17 It s A Gas and More! Energy Energy Experiment 17 It s A Gas and More! OUTCOMES After completing this lab activity, the student should be able to: explain a simple method for distinguishing carbon dioxide gas from oxygen gas.

More information

Investigation 12. The Hand Warmer Design Challenge: Where does the Heat come from?

Investigation 12. The Hand Warmer Design Challenge: Where does the Heat come from? Investigation 12 The Hand Warmer Design Challenge: Where does the Heat come from? Safety Solids are eye and skin irritants. CaCl 2 can cause skin burns. Wear googles at all times. Failure to do so will

More information

Unit 3, Lesson 02: Enthalpy Changes in Chemical Reactions

Unit 3, Lesson 02: Enthalpy Changes in Chemical Reactions Unit 3, Lesson 02: Enthalpy Changes in Chemical Reactions Chemical Potential Energy refers to the energy that is stored within an atom or molecule because of electrostatic attraction and repulsion between

More information

Lab #5 - Limiting Reagent

Lab #5 - Limiting Reagent Objective Chesapeake Campus Chemistry 111 Laboratory Lab #5 - Limiting Reagent Use stoichiometry to determine the limiting reactant. Calculate the theoretical yield. Calculate the percent yield of a reaction.

More information

Energy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy

Energy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy THERMOCHEMISTRY Thermodynamics Study of energy and its interconversions Energy is TRANSFORMED in a chemical reaction (POTENTIAL to KINETIC) HEAT (energy transfer) is also usually produced or absorbed -SYSTEM:

More information