DETERMINING AND USING H
|
|
- Hortense Garrison
- 6 years ago
- Views:
Transcription
1 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 a physical change, some physical property of the substance changes, although the identity of the substance remains the same. For example, the melting of ice to make liquid water is a physical change: H 2 O(s) H 2 O(l) However, when a piece of sodium metal is placed in water, a chemical change occurs. The element sodium reacts with water to make the compound sodium hydroxide and the element hydrogen: 2 Na(s) + 2 H 2 O(l) 2 NaOH (aq) + H 2 (g) When the process is complete, the original substances no longer exist. New substances, with new properties have been made. INTERNAL ENERGY Every change, whether physical or chemical, is accompanied by a change in the internal energy (E) of the system. In the case of melting ice, the molecules absorb heat from the surroundings. Their internal energy increases as they liquefy. In the reaction between sodium and water, the internal energy of these two substances decreases as sodium hydroxide and hydrogen are produced. The change in internal energy is symbolized by E. The first law of thermodynamics defines the change in internal energy as E = q + w, where q refers to the heat exchanged between reaction system and surroundings, and w refers to the work done by or on the reaction system. A sign convention here is important. With the reaction system as the point of reference, positive signs are used for q and w if the system absorbs heat or is worked upon. Negative signs are used if the reaction system loses heat or does work. MEASURING E AND H To measure E values, a sealed bomb calorimeter is required. In such a calorimeter, no work can be done. Therefore, w = 0 and E = q. This q is often labelled q V since the reaction is carried out at constant volume. In lab, simple calorimeters are usually used. They are open to the atmosphere. The reaction system can exchange both heat and work with the surroundings. However, the work component is difficult to measure. Furthermore, it is usually small compared to the heat component. For that reason, we ignore the work component and measure just the heat component. Since the atmospheric pressure is essentially constant for the duration of the reaction, we label the heat as q P. This value, q p, is not equal to E (since E = q + w, and w is not 0 in this case). The q P term has been named H and symbolizes the change in enthalpy. Enthalpy is similar to, but not the same as, internal energy. It is often called the "heat content" of a substance.
2 MEASURING HEAT Heat is an energy transfer that results because of a temperature difference between two things. Since it is a form of energy, heat has energy units, either Joules (J) or calories (cal). Heat flows from hot to cold. The energy transfer stops when the objects have reached the same temperature. The amount of heat lost equals the amount of heat gained. To calculate heat, we use the q equation: q = (m)(c s )( T) where m = mass, C s = specific heat (a unique constant for each substance) and T = change in temperature, defined as T FINAL T INITIAL. If T FINAL is higher than T INITIAL, then T is positive and q is positive. An object with a positive q has gained heat during the energy transfer. If T FINAL is lower than T INITIAL for an object, then its T is negative, causing its q to be negative. A negative q value for an object signifies that it has lost heat during the energy transfer. Heat exchanges between system and surroundings are measured in special containers called calorimeters. They may be as sophisticated as a bomb calorimeter, or simple as a Styrofoam coffee cup or thermos. The system is whatever substances undergo the change. The surroundings are all the other contents of the container as well as the container itself. If the system loses heat, all of it goes to the surroundings. Therefore, the ability of the container to absorb heat must first be established. Often, as in this experiment, a calorimeter constant, C CAL is determined. The value of C CAL equals the m(c s.) portion of the heat equation. Therefore, the q equation can be written as follows, when it is applied to a calorimeter: q = C CAL T H INFORMATION AND EQUATIONS Once H data has been determined for a reaction, it is often written at the end of the balanced equation. Its value corresponds to the balanced equation when interpreted in terms of moles. For example: H 2 O(s) H 2 O(l) H = +6.0 kj 2 Na(s) + 2 H 2 O(l) 2 NaOH(aq) + H 2 (g) H = 367 kj In the first case, when one mole of solid water (ice) undergoes melting, 6.0 kj of heat are absorbed by the water molecules. In the second case, when two moles of solid sodium react with two moles of liquid water, two moles of aqueous sodium hydroxide and one mole of gaseous hydrogen are produced, and 367 kj of heat are given off to the surroundings. Note that there is no such thing as positive or negative heat. The positive and negative signs simply signify the direction of heat flow, into or out of the system. HESS'S LAW Sometimes a chemical product is made in one step; in other cases, several steps may be required to make the desired product. For example, substance "E" can be made as follows: (Step 1) A + B C (Step 2) C + D E The net reaction can be found by adding the two steps: (Net) A + B + D E The C's in steps 1 and 2 cancel. The value of H for the net reaction can be found by adding the
3 H values for each step. If the values are: (Step 1) H = kj (Step 2) H = 300. kj then the value of H for the net reaction is 200. kj. PURPOSE OF THIS LAB In this lab, we will determine the value of H for two processes. One is a chemical change, the other is a physical change. Then, we will use this lab data as well as additional data for two other reactions to determine H for a fifth reaction by means of Hess's law. PROCEDURE A. Determination of calorimeter constant (C CAL ) 1. Place 50.0 ml of water at room temperature into a calorimeter, and record its temperature. For this and every other measurement, assume that the temperature of the calorimeter equals the temperature of its contents. 2. In a beaker on a hot plate, heat approximately 125 ml of water until its temperature is o C. Do not let the thermometer touch the bottom of the beaker as you heat. 3. Carefully measure 50.0 ml of the hot water in a graduated cylinder and record its temperature. 4. Immediately add the hot water to the water in the calorimeter. Stir the water and measure its final temperature. 5. Empty the calorimeter and dry it with a paper towel. Then repeat steps 1, 3 and 4 for a second trial. When finished, dry the calorimeter before beginning part B. B. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) 1. Measure out 50.0 ml of 2.00 M NH 3. Pour it into the calorimeter. Measure and record the temperature of the solution. 2. Measure out 50.0 ml of 2.00 M HCl in a clean, dry graduated cylinder. Measure and record its temperature. NOTE: The temperatures of the two solutions are probably almost the same. If they are not, use the average of the two as the initial temperature of the chemical system. 3. Add the HCl solution to the NH 3 solution in the calorimeter. Stir, and record the highest temperature reached. 4. Pour the contents of the calorimeter down the drain. Dry the calorimeter with a paper towel. When finished, dry the calorimeter before beginning part C.
4 C. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) 5. On the balance, weigh out a gram sample of solid ammonium chloride, NH 4 Cl. Record the actual mass you use. 6. Place 50.0 ml of room temperature water in the calorimeter. Measure and record its temperature. 7. Add the NH 4 Cl to the water. Stir and record the lowest temperature reached. 8. Pour the contents of the calorimeter down the drain. Dry the calorimeter with a paper towel.
5 MEASURING AND USING H Data Sheet Name Partner Be sure to use the correct number of significant figures for the volumes and temperatures you record below! A. Determination of calorimeter constant (C CAL ) BEFORE MIXING Trial 1 Trial 2 temperature of cold water (T INITIAL for cold) temperature of hot water (T INITIAL for hot) AFTER MIXING temperature of the water (T FINAL for water and calorimeter) B. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) BEFORE MIXING volume of 2.00 M NH 3 temperature of 2.00 M NH 3 volume of 2.00 M HCl temperature of 2.00 M HCl average temperature (T INITIAL for solution and calorimeter) AFTER MIXING temperature of mixture (T FINAL for solution and calorimeter) ml ml C. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) BEFORE MIXING Volume of H 2 O mass of NH 4 Cl(s) temperature of water (T INITIAL for solution and calorimeter) AFTER MIXING temperature of mixture (T FINAL for solution and calorimeter) ml g
6 MEASURING AND USING H Calculations Sheets Name Partner Show your work clearly, in the space provided, for each of the following calculations. Enter the answer on the line provided. The specific heat of water is J/gC o. Assume this is also the specific heat of the dilute aqueous solutions we use here. Also, watch signs (+ or ) carefully and think about their meanings. A. Determination of calorimeter constant (C CAL ) Trial 1 Trial 2 1. mass of the cold water used g g 2. mass of the hot water used g g 3. T COLD C o C o 4. T HOT C o C o 5. q for the hot water J J 6. q for the cold water J J 7. q for the calorimeter J J Recall that heat lost = heat gained. You know how much heat was lost by the hot water. Did every Joule go to the cold water? If not, assume the rest went to the calorimeter. 8. T CAL C o C o 9. C CAL J/C o J/C o 10. Average C CAL J/C o Use this average in any calculation below which requires C CAL.
7 B. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) 11. T SOLUTION C o 12. mass of solution g Its density is 1.03 g/ml 13. q for solution J q sol n = (m)(sp.ht.)( T) 14. q for calorimeter J q cal = C CAL x T CAL 15. q for surroundings J The q for the surroundings equals the q solution plus the q calorimeter. 16. q for reactant system J Watch your signs! 17. moles of NH 3 used mol Remember, you know the volume and the molarity. 18. moles of HCl used mol 19. Is there a limiting reactant? Explain: 20. H for one mole of limiting reactant J/mol 21. H (HINT: Look at units to do this conversion.) kj/mol
8 C. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) 22. T SOLUTION C o 23. mass of solution (NH 4 Cl and water) g 24. q for the solution J q sol n = (m)(sp.ht.)( T) 25. q for the calorimeter J q cal = C CAL x T CAL 26. q for the surroundings J 27. q for the reactant system J 28. moles of NH 4 Cl used mol 29. H for one mole of NH 4 Cl J/mol 30. H kj/mol
9 31. Application of Hess's law to the lab data You have now determined the value of H for a chemical change and a physical change involving ammonium chloride. Use your lab data as well as the data given below to determine the value of H for the decomposition reaction: NH 4 Cl(s) NH 3 (g) + HCl(g) Consider the following as you make your determination. (1) HCl(aq) + NH 3 (aq) NH 4 Cl(aq) H = kj (2) NH 4 Cl(s) NH 4 Cl(aq) H = kj (3) NH 3 (g) NH 3 (aq) H = 34.6 kj (4) HCl(g) HCl(aq) H = 75.1 kj Show all manipulated equations as well as your calculations here.
10
11 DETERMINING AND USING H Pre-Lab Assignment Name 1. How much heat is lost when 75.0 g. copper (sp. ht J/g o C) at 57.2 o C are cooled to 11.7 o C? 2. In an experiment a student obtained 450 J for the q calorimeter and 1150 J for the q solution. a. Calculate the q surroundings. (Watch your significant figures.) b. Calculate the q reactant system. 3. Manganese metal can be obtained by reaction of manganese dioxide with aluminum. 4Al (s) + 3MnO 2(s) 2Al 2 O 3(s) + 3Mn (s) Use Hess s Law to calculate H for this reaction using the following data. Show all calculations. H (kj) a. 2Al (s) O 2(g) Al 2 O 3(s) b. Mn (s) + O 2(g) MnO 2(s) -521
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 informationChemistry 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 informationEXPERIMENT 9 ENTHALPY OF REACTION HESS S LAW
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
More informationName: 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 informationName: 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 informationThermodynamics 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 informationExperiment #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 informationMOST 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 informationCalorimetry: Heat of Solution
Calorimetry: Heat of Solution When a substance undergoes a change in temperature, the quantity of heat lost or gained can be calculated using the following relationship: (heat) = m s T (1) The specific
More informationJust 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 informationThermochemistry: 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 informationThe 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 informationThermochemistry. Energy. 1st Law of Thermodynamics. Enthalpy / Calorimetry. Enthalpy of Formation
THERMOCHEMISTRY Thermochemistry Energy 1st Law of Thermodynamics Enthalpy / Calorimetry Hess' Law Enthalpy of Formation The Nature of Energy Kinetic Energy and Potential Energy Kinetic energy is the energy
More informationnot 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 information8 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 informationHESS 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 informationChapter 5 Thermochemistry. 許富銀 ( Hsu Fu-Yin)
Chapter 5 Thermochemistry 許富銀 ( Hsu Fu-Yin) 1 Thermodynamics The study of energy and its transformations is known as thermodynamics The relationships between chemical reactions and energy changes that
More informationExperiment #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 informationCalorimetric 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 informationTHE ENERGY OF THE UNIVERSE IS CONSTANT.
Chapter 6 Thermochemistry.notebook Chapter 6: Thermochemistry Jan 29 1:37 PM 6.1 The Nature of Energy Thermodynamics: The study of energy and its interconversions Energy: the capacity to do work or to
More informationCHEM 1105 S10 March 11 & 14, 2014
CHEM 1105 S10 March 11 & 14, 2014 Today s topics: Thermochemistry (Chapter 6) Basic definitions Calorimetry Enthalpy Thermochemical equations Calculating heats of reaction Hess s Law Energy and Heat Some
More informationLab #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 informationCOPYRIGHT 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 informationChemistry 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 informationThermochemistry: Heat and Chemical Change
Thermochemistry: Heat and Chemical Change 1 Heat or Thermal Energy (q) Heat is a form of energy Is heat the same as temperature? Heat flows between two objects at different temperatures. Hot Cold 2 Chemical
More informationName: General Chemistry Chapter 11 Thermochemistry- Heat and Chemical Change
Name: General Chemistry Chapter 11 Thermochemistry- Heat and Chemical Change Notepack 1 Section 11.1: The Flow of Energy Heat (Pages 293 299) 1. Define the following terms: a. Thermochemistry b. Energy
More informationChemistry 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 informationFirst Law of Thermodynamics: energy cannot be created or destroyed.
1 CHEMICAL THERMODYNAMICS ANSWERS energy = anything that has the capacity to do work work = force acting over a distance Energy (E) = Work = Force x Distance First Law of Thermodynamics: energy cannot
More informationExperiment 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 informationChemistry Chapter 16. Reaction Energy
Chemistry Reaction Energy Section 16.1.I Thermochemistry Objectives Define temperature and state the units in which it is measured. Define heat and state its units. Perform specific-heat calculations.
More informationExperiment 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 informationADDITIONAL 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 informationThe Nature of Energy. Chapter Six: Kinetic vs. Potential Energy. Energy and Work. Temperature vs. Heat
The Nature of Energy Chapter Six: THERMOCHEMISTRY Thermodynamics is the study of energy and its transformations. Thermochemistry is the study of the relationship between chemical reactions and energy changes
More informationEnthalpy 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 informationAdditivity 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 informationChapter 8. Thermochemistry 강의개요. 8.1 Principles of Heat Flow. 2) Magnitude of Heat Flow. 1) State Properties. Basic concepts : study of heat flow
강의개요 Basic concepts : study of heat flow Chapter 8 Thermochemistry Calorimetry : experimental measurement of the magnitude and direction of heat flow Thermochemical Equations Copyright 2005 연세대학교이학계열일반화학및실험
More information8.6 The Thermodynamic Standard State
8.6 The Thermodynamic Standard State The value of H reported for a reaction depends on the number of moles of reactants...or how much matter is contained in the system C 3 H 8 (g) + 5O 2 (g) > 3CO 2 (g)
More informationTo 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 informationAP 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 informationc 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 information17.2 Thermochemical Equations
17.2. Thermochemical Equations www.ck12.org 17.2 Thermochemical Equations Lesson Objectives Define enthalpy, and know the conditions under which the enthalpy change in a reaction is equal to the heat absorbed
More informationSlide 1 / Objects can possess energy as: (a) endothermic energy (b) potential energy (c) kinetic energy. a only b only c only a and c b and c
Slide 1 / 84 1 Objects can possess energy as: (a) endothermic energy (b) potential energy (c) kinetic energy A B C D E a only b only c only a and c b and c Slide 2 / 84 2 The internal energy of a system
More informationEXPERIMENT 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 informationName: Thermochemistry. Practice Test C. General Chemistry Honors Chemistry
Name: Thermochemistry C Practice Test C General Chemistry Honors Chemistry 1 Objective 1: Use the relationship between mass, specific heat, and temperature change to calculate the heat flow during a chemical
More informationLab #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 informationMeasuring 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 information1.4 Enthalpy. What is chemical energy?
1.4 Enthalpy What is chemical energy? Chemical energy is a form of potential energy which is stored in chemical bonds. Chemical bonds are the attractive forces that bind atoms together. As a reaction takes
More information3. When the external pressure is kpa torr, water will boil at what temperature? a C b C c. 100 C d. 18 C
Chemistry EOC Review 5: Physical Behavior of Matter 1. Which gas is monatomic at STP? a. chlorine b. fluorine c. neon d. nitrogen 2. What Kelvin temperature is equal to 25 C? a. 248 K b. 298 K c. 100 K
More informationThermodynamics 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 informationEnthalpies of Reaction
Enthalpies of Reaction Enthalpy is an extensive property Magnitude of H is directly related to the amount of reactant used up in a process. CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O(l) H = 890 kj 2CH 4 (g)
More informationIn 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 informationAccelerated Chemistry Study Guide Chapter 12, sections 1 and 2: Heat in Chemical Reactions
Accelerated Chemistry Study Guide Chapter 12, sections 1 and 2: Heat in Chemical Reactions Terms, definitions, topics Joule, calorie (Re-read p 57-58) Thermochemistry Exothermic reaction Endothermic reaction
More informationTable 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 informationChapter 5. Thermochemistry
Chapter 5 Thermochemistry Dr. A. Al-Saadi 1 Preview Introduction to thermochemistry: Potential energy and kinetic energy. Chemical energy. Internal energy, work and heat. Exothermic vs. endothermic reactions.
More informationEnthalpy and Internal Energy
Enthalpy and Internal Energy H or ΔH is used to symbolize enthalpy. The mathematical expression of the First Law of Thermodynamics is: ΔE = q + w, where ΔE is the change in internal energy, q is heat and
More informationChapter 6: Thermochemistry
Chapter 6: Thermochemistry Section 6.1: Introduction to Thermochemistry Thermochemistry refers to the study of heat flow or heat energy in a chemical reaction. In a study of Thermochemistry the chemical
More informationExperiment 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 informationENTHALPY, INTERNAL ENERGY, AND CHEMICAL REACTIONS: AN OUTLINE FOR CHEM 101A
ENTHALPY, INTERNAL ENERGY, AND CHEMICAL REACTIONS: AN OUTLINE FOR CHEM 101A PART 1: KEY TERMS AND SYMBOLS IN THERMOCHEMISTRY System and surroundings When we talk about any kind of change, such as a chemical
More informationAdditional Calculations: 10. How many joules are required to change the temperature of 80.0 g of water from 23.3 C to 38.8 C?
Additional Calculations: 10. How many joules are required to change the temperature of 80.0 g of water from 23.3 C to 38.8 C? q = m C T 80 g (4.18 J/gC)(38.8-23.3C) = 5183 J 11. A piece of metal weighing
More informationHESS 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 information11B, 11E Temperature and heat are related but not identical.
Thermochemistry Key Terms thermochemistry heat thermochemical equation calorimeter specific heat molar enthalpy of formation temperature enthalpy change enthalpy of combustion joule enthalpy of reaction
More informationEnergy and Chemical Change
Energy and Chemical Change Reviewing Vocabulary Match the definition in Column A with the term in Column B. h e d p c f a r m t j i s l u k n q g o Column A 1. The ability to do work or produce heat 2.
More informationTHERMOCHEMISTRY & DEFINITIONS
THERMOCHEMISTRY & DEFINITIONS Thermochemistry is the study of the study of relationships between chemistry and energy. All chemical changes and many physical changes involve exchange of energy with the
More informationSlide 2 / 118. Thermochemistry
Slide 1 / 118 Slide 2 / 118 Thermochemistry Slide 3 / 118 Table of Contents The Nature of Energy State Functions** Click on the topic to go to that section Enthalpy Measuring Enthalpy Changes: Calorimetry
More informationChapter 8 Thermochemistry: Chemical Energy. Chemical Thermodynamics
Chapter 8 Thermochemistry: Chemical Energy Chapter 8 1 Chemical Thermodynamics Chemical Thermodynamics is the study of the energetics of a chemical reaction. Thermodynamics deals with the absorption or
More informationChapter 5. Thermochemistry
Chapter 5 Thermochemistry Energy Thermodynamics Study of the relationship between heat, work, and other forms of energy Thermochemistry A branch of thermodynamics Focuses on the study of heat given off
More informationChapter 5 THERMO. THERMO chemistry. 5.4 Enthalpy of Reactions 5.5 Calorimetry 5.6 Hess s Law 5.7 Enthalpies of Formation
Chapter 5 THERMO THERMO chemistry 5.4 Enthalpy of Reactions 5.5 Calorimetry 5.6 Hess s Law 5.7 Enthalpies of Formation Chemical Equations 1 st WRITE the Chemical Equation 2 nd BALANCE the Chemical Equation
More informationThermochemistry Chapter 4
Thermochemistry Chapter 4 Thermochemistry is the study of energy changes that occur during chemical reactions Focus is on heat and matter transfer between the system and the surroundings Energy The ability
More informationSection 9: Thermodynamics and Energy
Section 9: Thermodynamics and Energy The following maps the videos in this section to the Texas Essential Knowledge and Skills for Science TAC 112.35(c). 9.01 Law of Conservation of Energy Chemistry (11)(A)
More informationCalorimetry 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 informationCHAPTER 17 Thermochemistry
CHAPTER 17 Thermochemistry Thermochemistry The study of the heat changes that occur during chemical reactions and physical changes of state. Chemical Change: new substances created during chemical reaction
More informationName: Class: Date: ID: A
Name: Class: _ Date: _ ID: A Chpter 17 review Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of these phase changes is an endothermic process? a.
More information= (25.0 g)(0.137 J/g C)[61.2 C - (-31.4 C)] = 317 J (= kj)
CHEM 101A ARMSTRONG SOLUTIONS TO TOPIC D PROBLEMS 1) For all problems involving energy, you may give your answer in either joules or kilojoules, unless the problem specifies a unit. (In general, though,
More informationEnergy 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 informationThermochemistry. Questions to ponder. Because 4/20/14. an ice-cube? an ice-cube? Part 2: Calorimetry. But I KNOW. Q=mc T, but T=0
Thermochemistry Part 2: Calorimetry p p If you leave your keys and your chemistry book sitting in the sun on a hot summer day, which one is hotter? Why is there a difference in temperature between the
More informationThermodynamics. 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 informationCh. 17 Thermochemistry
Ch. 17 Thermochemistry 17.1 The Flow of Energy Energy Transformations Thermochemistry: study of energy changes in chemical reactions and changes in state Chemical potential energy: energy stored in bonds
More informationName Date Class THE FLOW OF ENERGY HEAT AND WORK
17.1 THE FLOW OF ENERGY HEAT AND WORK Section Review Objectives Explain the relationship between energy, heat, and work Distinguish between exothermic and endothermic processes Distinguish between heat
More informationThermodynamics. 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 informationThermochemistry Notes
Name: Thermochemistry Notes I. Thermochemistry deals with the changes in energy that accompany a chemical reaction. Energy is measured in a quantity called enthalpy, represented as H. The change in energy
More informationAP CHEMISTRY NOTES 4-1 THERMOCHEMISTRY: ENTHALPY AND ENTROPY
AP CHEMISTRY NOTES 4-1 THERMOCHEMISTRY: ENTHALPY AND ENTROPY Reaction Rate how fast a chemical reaction occurs Collision Theory In order for a chemical reaction to occur, the following conditions must
More informationThermochemistry: Part of Thermodynamics
Thermochemistry: Part of Thermodynamics Dr. Vickie M. Williamson @vmwilliamson Student Version 1 Chemical Thermodynamics! Thermodynamics: study of the energy changes associated with physical and chemical
More informationThermochemistry: Energy Flow and Chemical Reactions
Thermochemistry: Energy Flow and Chemical Reactions Outline thermodynamics internal energy definition, first law enthalpy definition, energy diagrams, calorimetry, theoretical calculation (heats of formation
More informationCALORIMETRY. 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 informationThermochemistry: The Heat of Neutralization
Thermochemistry: The Heat of Neutralization Safety Solid NaOH is a severe contact hazard. Avoid touching it! HCl and NaOH solutions are both contact hazards. Wear goggles at all times since NaOH is a severe
More informationC 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 informationChapter 6. Thermochemistry
Chapter 6. Thermochemistry 1 1. Terms to Know: thermodynamics thermochemistry energy kinetic energy potential energy heat heat vs. temperature work work of expanding gases work of expanding gases under
More informationMr Chiasson Advanced Chemistry 12 / Chemistry 12 1 Unit B: Thermochemical Changes
Mr Chiasson Advanced Chemistry 12 / Chemistry 12 1 Unit B: Thermochemical Changes Students will be expected to: Compare the molar enthalpies of several combustion reactions involving organic compounds.
More informationThermochemistry is the study of the relationships between chemical reactions and energy changes involving heat.
CHEM134- F18 Dr. Al- Qaisi Chapter 06: Thermodynamics Thermochemistry is the study of the relationships between chemical reactions and energy changes involving heat. Energy is anything that has the capacity
More informationThermochemistry. Energy. 1st Law of Thermodynamics. Enthalpy / Calorimetry. Enthalpy of Formation
Thermochemistry Energy 1st Law of Thermodynamics Enthalpy / Calorimetry Hess' Law Enthalpy of Formation The Nature of Energy Kinetic Energy and Potential Energy Kinetic energy is the energy of motion:
More informationLab 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 informationCalorimetry 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 informationChapter 6 Energy and Chemical Change. Brady and Senese 5th Edition
Chapter 6 Energy and Chemical Change Brady and Senese 5th Edition Index 6.1 An object has energy if it is capable of doing work 6.2 Internal energy is the total energy of an object s molecules 6.3 Heat
More informationTHER 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 informationENTHALPY 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 informationENERGY AND ENERGETICS PART ONE Keeping Track of Energy During a Chemical Reaction
ENERGY AND ENERGETICS PART ONE Keeping Track of Energy During a Chemical Reaction ADEng. PROGRAMME Chemistry for Engineers Prepared by M. J. McNeil, MPhil. Department of Pure and Applied Sciences Portmore
More informationTo calculate heat (q) for a given temperature change: heat (q) = (specific heat) (mass) ( T) where T = T f T i
Use your textbook or other resources available to answer the following questions General Information: Thermochemistry Phase Change A change in the physical form/state but not a change in the chemical identity
More information1 of 5. Last time: we finished: titration, dilutions Questions on the test? Today: Energy and chemistry: Thermochemistry
1 of 5 Notes for chem 101 lecture 7b 0) admin Test 2 is on Feb 24 (Wed). 2 Furloughs are coming up: Fri Feb 19 and Mon Feb 22. The test will be on chapters 4-5. (stoichiometry). Review session will be
More informationChapter 5 Thermochemistry
Chapter 5 Thermochemistry Energy -Very much a chemistry topic Every chemical change has an accompanying change of. Combustion of fossil fuels The discharging a battery Metabolism of foods If we are to
More informationQuantities in Chemical Reactions
Quantities in Chemical Reactions 6-1 6.1 The Meaning of a Balanced Equation C 3 H 8(g) + 5 O 2(g) 3 CO 2(g) + 4 H 2 O (g) The balanced equation tells us: 1 molecule of propane reacts with 5 molecules of
More information