CHM112 Lab Determination of an Equilibrium Constant Grading Rubric

Size: px
Start display at page:

Download "CHM112 Lab Determination of an Equilibrium Constant Grading Rubric"

Transcription

1 Name Team Name CHM112 Lab Determination of an Equilibrium Constant Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial concentrations completed before coming to lab. 2 Safety and proper waste disposal procedures observed 2 Followed procedure correctly without depending too much on instructor or lab partner 3 Work space and glassware was cleaned up 1 Lab Report ICE tables and K calculations complete and shown in detail. 5 Question 1 1 Question 2 1 Question 3 1 Question 4 1 Total 20 Subject to additional penalties at the discretion of the instructor.

2 Determination of an Equilibrium Constant Introduction It is frequently assumed that reactions go to completion, that all of the reactants are converted into products. Most chemical reactions do not go to completion because they are equilibrium systems where the reaction proceeds in both directions. As the reactants are used up, the rate of the forward reaction decreases. Conversely, as the concentrations of the products increase, the rate of the reverse reaction increases. Eventually, the rate of the forward reaction equals the rate of the reverse reaction and the concentrations of the reactants and the products stay constant. The system has reached a state of dynamic equilibrium. At equilibrium, both the forward and reverse reactions are occuring, but no net change is observed. Consider the general reaction: aa + bb cc + dd ( 1 ) where a,b,c and d are the stoiochiometric coefficicents. Experimental evidence shows that the ratio of products to reactants (with each product and reactant expressed as a molar concentration and raised to its stoichiometric coefficient) is a constant for a reaction that has reached equilibrium. This constant, which is different for each chemical reaction, is known as the equilibrium constant and is designated with the letter K. There is a separate value of K for each temperature at which the reaction occurs. Thus, at equilibrium, the equilibrium constant K is equal to: [ ] c C [ D ] K = a [ A] [ B] d b ( 2 ) where the brackets [ ] imply molarity and the exponents are the stoichiometric coeffients of the balanced chemical equation. The equilibrium constant measures the extent to which a chemical reaction occurs. The larger the value for K, the greater the tendency for the reaction to go to completion is and the more products will be formed relative to the reactants. In this experiment you will determine the equilibrium constant for the following reaction: (Spectator ions are not shown.) Fe 3+ (aq) + HSCN (aq) FeSCN 2+ (aq) + H + (aq) ( 3 ) 2+ + [ FeSCN ][ H ] K = 3+ [ Fe ][ HSCN] ( 4 ) Solutions of Fe 3+ and HSCN will be mixed and will react to form some FeSCN 2+ and H +. The initial amounts of Fe 3+ and HSCN can be calculated. The equilibrium concentration of FeSCN 2+ will be found using its spectroscopic properties how much light it absorbs at a specific wavelength. FeSCN 2+ is a blood red complex that absorbs the bluegreen wavelengths of visible light. Its absorbance is directly proportional to its concentration. The absorbance (a measure of the amount of light absorbed) will be measured by a spectrophotometer. Solutions to be measured are placed in cuvettes; these are sqaure tubes have minimal absorbance in the wavelength range of the spectrophotometer.

3 A cuvette for measureing light absorption. It is usually made of quartz or plastic. On some, two of the sides are frosted. For a solution placed in a 1 cm cuvette, the absorbance, A, is equal to the extinction coefficient, ε (epsilon), times the molar concentration, C. The value of ε is can be determined experimentally for each substance from solutions of known concentration at a particualr wavelength. ε varies with the wavelength of light. In this experiment we will be measuring absorbtion at 450 nm. A = ε C ( 5 ) For the FeSCN 2+, ε at 450 nm equals 4400, so the equilibrium concentration of FeSCN 2+ will equal your measured absorbance divided by Using an equilibrium (ICE) chart, the equilibrium concentrations of Fe 3+ and HSCN are then calculated. Finally, the equilibrium concentrations are put into equation ( 4 ) to find the equilibrium constant, K. Note: All of the solutions are made in 0.20M HNO 3 (aq) so the initial concentration of [H + ] is at 0.20M. Equipment two 25 ml volumetric flasks 3 test tubes 50 ml beaker 4 cuvettes stirring rod Thermoscientific Evolution 60 Spectrophotometer 5 ml pipettes Chemicals 0.20 M HNO 3 (aq), nitric acid M KSCN(aq), potassium thiocyanate (source of HSCN) 0.10 M Fe(NO 3 ) 3 (aq), iron (III) nitrate dissolved in 0.20M HNO 3 (aq). (Source of Fe 3+ ) Spill/Disposal The contents of all test tubes, volumetric flasks and beakers may be disposed of in the sink. Flush with a large volume of water.

4 Procedure

5 10. Measure the temperature of each solution. (Remember that K is temperature dependent.) Spectrophotometric measurement: 11. Obtain 4 cuvettes. Fill one (to the mark) with 0.20 M HNO 3 (aq). This will be used as the standard/blank. (All solutions have been prepared in 0.20 M HNO 3 (aq), and the absorbance of 0.20 M HNO 3 (aq) will be set to zero.) 12. Fill the other three other cuvettes to the line, each with one of the three test tube solutions. 13. Use Kimwipes to carefully wipe off any fingerprints and moisture from the cuvette. Fingerprints or other residue on the cuvette can affect the reading. 14. Open the lid of the spectrophotometer. If two sides of the cuvette are frosted, be sure that light will pass through the clear sides as you insert the cuvettes. Insert the blank in the B slot of the sample holder and insert the other samples in slots 1, 2, and 3 corresponding to the test tube they came from. Close the lid. 15. Press the the leftmost arrow key under the screen where it says measure blank to measure the baseline absorbance of 0.20 M HNO 3 (aq). 16. From the cell position keys, select the sample you want to measure (buttons labeled as 1, 2, and 3), then record the absorbance on your data sheet. Calculations: 1. Taking into account the dilutions in steps 1 9 of the procedure, calculate the initial concentrations of [Fe 3+ ] and [HSCN ] in each of the three test tubes. Show these calculations on the sheet titled Calculation of Initial Concentrations. Complete the calculations on this sheet before coming to lab. This will count towards your lab grade. Record these initial concentrations on the data sheet. This sheet must be handed in as directed by your instructor. 2. Using the absorbance values obtained and the value of ε, 4400, calculate the equilibrium concentrations of [FeSCN 2+ ] in each cuvette. 3. Use the stoichiometric relationships in equation (3) and ICE chart to find the equilibrium concentrations of [Fe 3+ ] and [HSCN ]. 4. Plug these values into the equilibrium expression (4) and calculate K. Do this for all three solutions. Disposal The contents of all test tubes, volumetric flasks and beakers may be disposed of in the sink. Flush with a large volume of water

6 Determination of an Equilibrium Constant: Initial Calculations Name Calculate the initial concentration of Fe 3+ and HSCN in the three test tubes before coming to lab. This will count towards your lab grade. Test Tube 1 Volume of stock Fe used Concentration of Stock Fe solution Volume of stock HSCN used Concentration of Stock HSCN solution 5.0 ml 1.0 x 10-2 M 5.0 ml 1.0 x 10-3 M Total volume after mixing Concentration of Fe after mixing (Use M 1 V 1 = M 2 V 2 ) This is the initial concentration of Fe 3+ in test tube 1. Record this number on data sheet. Concentration of HSCN after mixing (Use M 1 V 1 = M 2 V 2 ) This is the initial concentration of HSCN in test tube 1. Record this number on data sheet. Test Tube 2 Volume of Fe D1 used: Concentration of Fe D1: Volume of stock HSCN used Concentration of stock HSCN solution Total volume after mixing Concentration of Fe after mixing Concentration of HSCN after mixing Test tube 3 Volume of Fe D2 used: Concentration of Fe D2: Volume of stock HSCN used Concentration of stock HSCN solution Total volume after mixing Concentration of Fe after mixing Concentration of HSCN after mixing Report Page 1 of 4

7 Determination of an Equilibrium Constant: Data and Calculations Name Note the initial concentrations from your calculations on this sheet before coming to lab Test Tube [Fe 3+ ] initial [HSCN] initial Test Tube Absorbance [FeSCN 2+ ] eq (C = A/4400) ICE Charts (Fill in charts and show all the calculations clearly) 1. From Test Tube 1 I Fe 3+ + HCSN FeSCN 2+ + H + C E K= Report Page 2 of 4

8 Determination of an Equilibrium Constant: Calculations Name 2. From Test Tube 2 I Fe 3+ + HCSN FeSCN 2+ + H + C E K= 3. From Test Tube 3 I Fe 3+ + HCSN FeSCN 2+ + H + C E K= Average K= Report Page 3 of 4

9 Determination of an Equilibrium Constant: Post Lab Name 1. Consider the following hypothetical reaction at equilibrium 2A (g) + B (g) 2C (g) At 200 K, the value of the equilibrium constant K c = Based on this K c, what can you say about the position of the equilibrium? In other words, how do you know if the equilibrium favors the reactants or the products? 2. The reaction you studied was Fe 3+ (aq) + HSCN (aq) FeSCN 2+ (aq) + H + (aq) Based on your calculated K value, calculate the value of K for the following reaction FeSCN 2+ (aq) + H + (aq) Fe 3+ (aq) + HSCN (aq) 1. If you had a fourth sample where the absorbance of the FeSCN 2+ (aq) was 0.145, What was the concentration of FeSCN 2+ (aq)? 3. Which, if any, of the following would affect the value of the equilibrium constant found in this lab? a) adding a catalyst to the system b) changing the temperature. Report Page 4 of 4

Experiment #7. Determination of an Equilibrium Constant

Experiment #7. Determination of an Equilibrium Constant Experiment #7. Determination of an Equilibrium Constant Introduction It is frequently assumed that reactions go to completion, that all of the reactants are converted into products. Most chemical reactions

More information

#11. Chemical Equilibrium

#11. Chemical Equilibrium #11. Chemical Equilibrium Goal To observe and explain equilibrium shifts based on Le Chatelier s Principle. Introduction In any chemical reaction, reactants are converted to products. In some cases, some

More information

aa + bb cc + dd Equation 1

aa + bb cc + dd Equation 1 Experiment: The Determination of K eq for FeSCN 2+ Introduction For any reversible chemical reaction at equilibrium, the concentrations of all reactants and products are constant or stable. There is no

More information

Spectrophotometric Determination of an Equilibrium Constant

Spectrophotometric Determination of an Equilibrium Constant Spectrophotometric Determination of an Equilibrium Constant v021214 Objective To determine the equilibrium constant (K c ) for the reaction of iron (III) ion with thiocyanate (SCN - ) to form the thiocyanatoiron(iii)

More information

CHM 152 updated May 2011 Lab 6: Experimentally Determining an Equilibrium Constant using Spectrophotometry

CHM 152 updated May 2011 Lab 6: Experimentally Determining an Equilibrium Constant using Spectrophotometry CHM 152 updated May 2011 Lab 6: Experimentally Determining an Equilibrium Constant using Spectrophotometry Introduction In this lab you will experimentally determine the equilibrium constant with respect

More information

The Determination of an Equilibrium Constant

The Determination of an Equilibrium Constant The Determination of an Equilibrium Constant Calculator 10 Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium

More information

Lab #12: Determination of a Chemical Equilibrium Constant

Lab #12: Determination of a Chemical Equilibrium Constant Lab #12: Determination of a Chemical Equilibrium Constant Objectives: 1. Determine the equilibrium constant of the formation of the thiocyanatoiron (III) ions. 2. Understand the application of using a

More information

AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2+

AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2+ AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2 Lab days: Thursday and Friday, February 22-23, 2018 Lab due: Tuesday, February 27, 2018 Goal (list in your lab book): The

More information

Lab #16: Determination of the Equilibrium Name: Constant of FeSCN 2+ Lab Exercise. 10 points USE BLUE/BLACK INK!!!! Date: Hour:

Lab #16: Determination of the Equilibrium Name: Constant of FeSCN 2+ Lab Exercise. 10 points USE BLUE/BLACK INK!!!! Date: Hour: Lab #16: Determination of the Equilibrium Name: Constant of FeSCN 2+ Lab Exercise Chemistry II Partner: 10 points USE BLUE/BLACK INK!!!! Date: Hour: Goal: The goal of this lab is to determine the equilibrium

More information

CHEM Lab 7: Determination of an Equilibrium Constant using Spectroscopy

CHEM Lab 7: Determination of an Equilibrium Constant using Spectroscopy CHEM 0012 Lab 7: Determination of an Equilibrium Constant using Spectroscopy 1 Determination of the equilibrium constant of the following equilibrium system at room temperature. Fe 3+ (aq) + SCN- (aq)

More information

Chemical Equilibrium: Finding a Constant, Kc

Chemical Equilibrium: Finding a Constant, Kc Chemical Equilibrium: Finding a Constant, Kc Experiment 20 The purpose of this lab is to experimentally determine the equilibrium constant, K c, for the following chemical reaction: Fe 3+ (aq) + SCN (aq)

More information

Experimental Procedure Overview

Experimental Procedure Overview Lab 4: Determination of an Equilibrium Constant using Spectroscopy Determination of the equilibrium constant of the following equilibrium system at room temperature. Fe 3+ (aq) + SCN (aq) Fe(SCN) 2+ (aq)

More information

Lab 13.3 Determining K c via Colorimetry

Lab 13.3 Determining K c via Colorimetry BACKGROUND Most chemical reactions are reversible. They will proceed forward to a point where the products they have formed begin to collide with one another and reform the original reactants. When the

More information

of the ferric thiocyanate. This was done by creating the solutions and putting them into a

of the ferric thiocyanate. This was done by creating the solutions and putting them into a Introduction: The equation of the reaction is Fe 3+ (aq) + SCN - (aq) Fe(NCS) 2+ (aq). The objective of this lab was to determine the equilibrium constant (K) for the formation of the ferric thiocyanate.

More information

CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric

CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric Name Team Name CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial concentrations completed

More information

The Determination of an Equilibrium Constant

The Determination of an Equilibrium Constant The Determination of an Equilibrium Constant Computer 10 Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium

More information

Experiment 12H, Parts A and B

Experiment 12H, Parts A and B Experiment 12H, Parts A and B AHRM 8/17 PRINCIPLES OF EQUILIBRIUM AND THERMODYNAMICS MATERIALS: PURPOSE: 0.0200 M Fe(NO 3 ) 3 in 1 M HNO 3, 0.000200 M KSCN, 2.0 M HNO 3, solid Fe(NO 3 ) 3. 9H 2 O with

More information

CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric

CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric Name Team Name CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial concentrations completed

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

K = [C]c [D] d [A] a [B] b (5)

K = [C]c [D] d [A] a [B] b (5) Chem 1B Dr. White 19 Experiment 3: Determination of an Equilibrium Constant Objectives To determine the equilibrium constant for a reaction. Introduction Equilibrium is a dynamic state in which, at a given

More information

Experiment #5. Iodine Clock Reaction Part 1

Experiment #5. Iodine Clock Reaction Part 1 Experiment #5. Iodine Clock Reaction Part 1 Introduction In this experiment you will determine the Rate Law for the following oxidation- reduction reaction: 2 H + (aq) + 2 I (aq) + H 2 O 2 (aq) I 2 (aq)

More information

DETERMINATION OF K c FOR AN EQUILIBRIUM SYSTEM

DETERMINATION OF K c FOR AN EQUILIBRIUM SYSTEM DETERMINATION OF K c FOR AN EQUILIBRIUM SYSTEM 1 Purpose: To determine the equilibrium constant K c for an equilibrium system using spectrophotometry to measure the concentration of a colored complex ion.

More information

Determination of an Equilibrium Constant

Determination of an Equilibrium Constant 7 Determination of an Equilibrium Constant Introduction When chemical substances react, the reaction typically does not go to completion. Rather, the system goes to some intermediate state in which the

More information

DETERMINATION OF AN EQUILIBRIUM CONSTANT

DETERMINATION OF AN EQUILIBRIUM CONSTANT DETERMINATION OF AN EQUILIBRIUM CONSTANT In this experiment the equilibrium properties of the reaction between the iron(iii) ion and the thiocyanate ion will be studied. The relevant chemical equation

More information

The Determination of an Equilibrium Constant

The Determination of an Equilibrium Constant The Determination of an Equilibrium Constant Chemistry 102 10 Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium

More information

THE IRON(III) THIOCYANATE REACTION SYSTEM

THE IRON(III) THIOCYANATE REACTION SYSTEM Experiment 7 THE IRON(III) THIOCYANATE REACTION SYSTEM Prepared by Ross S. Nord, Chemistry Department, Eastern Michigan University PURPOSE To investigate a novel reaction system by utilizing a spectrophotometer.

More information

Experiment 7: SIMULTANEOUS EQUILIBRIA

Experiment 7: SIMULTANEOUS EQUILIBRIA Experiment 7: SIMULTANEOUS EQUILIBRIA Purpose: A qualitative view of chemical equilibrium is explored based on the reaction of iron(iii) ion and thiocyanate ion to form the iron(iii) thiocyanate complex

More information

Chemical Equilibrium: Finding a Constant, Kc

Chemical Equilibrium: Finding a Constant, Kc Chemical Equilibrium: Finding a Constant, Kc Computer 20 The purpose of this lab is to experimentally determine the equilibrium constant, K c, for the following chemical reaction: Fe 3+ (aq) + SCN (aq)

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

D E T E R M I N A T I O N O F K e q L A B

D E T E R M I N A T I O N O F K e q L A B South Pasadena Honors Chemistry Name 8 Equilibrium Period Date D E T E R M I N A T I O N O F K e q L A B Lab Overview In a reversible reaction, equilibrium is the state at which the rates of forward and

More information

Experiment 8: DETERMINATION OF AN EQUILIBRIUM CONSTANT

Experiment 8: DETERMINATION OF AN EQUILIBRIUM CONSTANT Experiment 8: DETERMINATION OF AN EQUILIBRIUM CONSTANT Purpose: The equilibrium constant for the formation of iron(iii) thiocyanate complex ion is to be determined. Introduction: In the previous week,

More information

Experiment 6: Determination of the Equilibrium Constant for Iron Thiocyanate Complex

Experiment 6: Determination of the Equilibrium Constant for Iron Thiocyanate Complex Experiment 6: Determination of the Equilibrium Constant for Iron Thiocyanate Complex The data for this lab will be taken as a class to get one data set for the entire class. I. Introduction A. The Spectrophotometer

More information

Experimental Procedure Lab 402

Experimental Procedure Lab 402 Experimental Procedure Lab 402 Overview One set of solutions having known molar concentrations of FeNCS 2+ is prepared for a calibration curve, a plot of absorbance versus concentration. A second set of

More information

CHM111 Lab Titration of Vinegar Grading Rubric

CHM111 Lab Titration of Vinegar Grading Rubric Name Team Name CHM111 Lab Titration of Vinegar Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Safety and proper waste disposal

More information

CHEMISTRY 135 General Chemistry II. Determination of an Equilibrium Constant

CHEMISTRY 135 General Chemistry II. Determination of an Equilibrium Constant CHEMISTRY 135 General Chemistry II Determination of an Equilibrium Constant Show above is a laboratory sample from chemistry, not phlebotomy. [1] Is the bloody-looking product the main component of this

More information

THE TEMPERATURE DEPENDENCE OF THE EQUILIBRIUM CONSTANT

THE TEMPERATURE DEPENDENCE OF THE EQUILIBRIUM CONSTANT Experiment 7B THE TEMPERATURE DEPENDENCE OF THE EQUILIBRIUM CONSTANT Prepared by Ross S. Nord, Chemistry Department, Eastern Michigan University PURPOSE To investigate the relationship between the equilibrium

More information

#12. Acids and Bases.

#12. Acids and Bases. #12. Acids and Bases. Goals: To determine the ph of common substances and observe buffer behavior. Background Acids and bases are very common in chemistry and biology. Understanding acids and bases is

More information

Experiment #8. LeChatelier s Principle

Experiment #8. LeChatelier s Principle Experiment #8. LeChatelier s Principle Aim: To study the effect of concentration and temperature on chemical equilibrium When the rate of the forward reaction becomes equal to the rate of the reverse reaction,

More information

Experiment #7. Titration of Vinegar

Experiment #7. Titration of Vinegar Experiment #7. Titration of Vinegar Goals 1. To determine the mass percent of acetic acid in a solution via titration. 2. To master the technique of titration. Introduction Vinegar is a common household

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

Chemical Equilibrium: Finding a Constant, Kc

Chemical Equilibrium: Finding a Constant, Kc Lab12 Chemical Equilibrium: Finding a Constant, Kc The purpose of this lab is to experimentally determine the equilibrium constant, K c, for the following chemical reaction: Fe 3+ (aq) + SCN (aq) FeSCN

More information

Chemical Equilibrium: Finding a Constant, Kc

Chemical Equilibrium: Finding a Constant, Kc Chemical Equilibrium: Finding a Constant, Kc Experiment 20 The purpose of this lab is to experimentally determine the equilibrium constant, K c, for the following chemical reaction: Fe 3+ (aq) + SCN -

More information

Equilibrium and Ionic Strength Effects

Equilibrium and Ionic Strength Effects Equilibrium and Ionic Strength Effects Objectives You will determine the thermodynamic equilibrium constant for the reaction between iron(iii) ion and thiocyanate ion to form iron(iii)-thiocyanate. Fe

More information

1iI1E. The Determination of 0 an Equilibrium Constant [LU. Computer

1iI1E. The Determination of 0 an Equilibrium Constant [LU. Computer Computer The Determination of 0 an Equilibrium Constant Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium constant,

More information

9 Equilibrium. Aubrey High School PreAP -Chemistry. Name Period Date / /

9 Equilibrium. Aubrey High School PreAP -Chemistry. Name Period Date / / Aubrey High School PreAP -Chemistry 9 Equilibrium Name Period Date / / 9.2 Determination of Keq Lab - Equilibrium Problems Lab Overview In a reversible reaction, equilibrium is the state at which the rates

More information

The Determination of an Equilibrium Constant

The Determination of an Equilibrium Constant LabQuest 10 The equilibrium state of a chemical reaction can be characterized by quantitatively defining its equilibrium constant, Keq. In this experiment, you will determine the value of Keq for the reaction

More information

Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.1.16

Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.1.16 Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.1.16 I. Introduction Equilibrium Consider the following situation: It is rush hour

More information

Experiment #9. Atomic Emission Spectroscopy

Experiment #9. Atomic Emission Spectroscopy Introduction Experiment #9. Atomic Emission Spectroscopy Spectroscopy is the study of the interaction of light with matter. This interaction can be in the form of the absorption or the emission of electromagnetic

More information

Chemistry 112 Laboratory Experiment 7: Determination of Reaction Stoichiometry and Chemical Equilibrium

Chemistry 112 Laboratory Experiment 7: Determination of Reaction Stoichiometry and Chemical Equilibrium Chemistry 112 Laboratory Experiment 7: Determination of Reaction Stoichiometry and Chemical Equilibrium Introduction The word equilibrium suggests balance or stability. The fact that a chemical reaction

More information

Determination of the Equilibrium Constant for the Iron (III) thiocynate Reaction

Determination of the Equilibrium Constant for the Iron (III) thiocynate Reaction Lab 4. Determination of the Equilibrium Constant for the Iron (III) thiocynate Reaction Prelab Assignment Before coming to lab: After reading "Lab Notebook Policy and Format for Lab Reports" handout, complete

More information

Experiment 7A ANALYSIS OF BRASS

Experiment 7A ANALYSIS OF BRASS Experiment 7A ANALYSIS OF BRASS FV 10/21/10 MATERIALS: Spectronic 20 spectrophotometers, 2 cuvettes, brass sample, 7 M HNO 3, 0.100 M CuSO 4, 2 M NH 3, two 50 ml beakers, 100 ml beaker, two 25 ml volumetric

More information

Chemistry 112 SPECTROPHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT

Chemistry 112 SPECTROPHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT Chemistry 112 SPECTROPHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT INTRODUCTION The principle underlying a spectrophotometric method of analysis involves the interaction of electromagnetic radiation

More information

Finding the Constant K c 4/21/15 Maya Parks Partners: Ben Seufert, Caleb Shumpert. Abstract:

Finding the Constant K c 4/21/15 Maya Parks Partners: Ben Seufert, Caleb Shumpert. Abstract: Finding the Constant K c 4/21/15 Maya Parks Partners: Ben Seufert, Caleb Shumpert Abstract: This lab was performed to find the chemical equilibrium constant K c for the reaction Fe 3+ + SCN FeSCN 2+ using

More information

C H E M I S T R Y DETERMINATION OF AN EQUILIBRIUM CONSTANT

C H E M I S T R Y DETERMINATION OF AN EQUILIBRIUM CONSTANT C H E M I S T R Y 1 5 0 Chemistry for Engineers DETERMINATION OF AN EQUILIBRIUM CONSTANT DEPARTMENT OF CHEMISTRY UNIVERSITY OF KANSAS Determination of an Equilibrium Constant Introduction A system is at

More information

Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III)

Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III) Chem 1B Dr. White 11 Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III) Objectives To use spectroscopy to relate the absorbance of a colored solution to its concentration. To prepare a Beer s

More information

Skill Building Activity 2 Determining the Concentration of a Species using a Vernier Spectrometer

Skill Building Activity 2 Determining the Concentration of a Species using a Vernier Spectrometer Skill Building Activity 2 Determining the Concentration of a Species using a Vernier Spectrometer Purpose To use spectroscopy to prepare a Beer s Law plot of known dilutions of copper(ii) sulfate so that

More information

Lab 04 Equilibrium Constant of Ferric Thiocyanate

Lab 04 Equilibrium Constant of Ferric Thiocyanate Lab 04 Equilibrium Constant of Ferric Thiocyanate Introduction This experiment will give you an opportunity to determine the equilibrium constant for the formation of Fe(SCN) 2+. The experiment will require

More information

A = km (6) A = k [FeSCN 2+ ] KNOWN [FeSCN 2+ ] MEASURED A (Spec 20) CALCULATED k 3.0 x x x x 10-5 AVERAGE k =

A = km (6) A = k [FeSCN 2+ ] KNOWN [FeSCN 2+ ] MEASURED A (Spec 20) CALCULATED k 3.0 x x x x 10-5 AVERAGE k = Method I. Analysis by Spectrophotometric Measurement We ll be using the spectrophotometer ( Spec 20 ) to compare absorbances (A) indicated by the equipment and known concentrations of iron(iii) thiocyanate

More information

Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III)

Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III) Chem 1B Saddleback College Dr. White 1 Experiment 2: The Beer-Lambert Law for Thiocyanatoiron (III) Objectives To use spectroscopy to relate the absorbance of a colored solution to its concentration. To

More information

Experiment #7. Chemical Reactions.

Experiment #7. Chemical Reactions. Experiment #7. Chemical Reactions. Goals To observe chemical reactions and balance chemical equations. Background Chemical and Physical Changes Changes in matter are often classified as either physical

More information

Experiment 1. Chemical Equilibria and Le Châtelier s Principle

Experiment 1. Chemical Equilibria and Le Châtelier s Principle Experiment 1 Chemical Equilibria and Le Châtelier s Principle A local theatre company is interested in preparing solutions that look like blood for their upcoming production of Lizzie Borden. They have

More information

Experiment 18 - Absorption Spectroscopy and Beer s Law: Analysis of Cu 2+

Experiment 18 - Absorption Spectroscopy and Beer s Law: Analysis of Cu 2+ Experiment 18 - Absorption Spectroscopy and Beer s Law: Analysis of Cu 2+ Many substances absorb light. When light is absorbed, electrons in the ground state are excited to higher energy levels. Colored

More information

CHM101 Lab Chemical Reactions Grading Rubric

CHM101 Lab Chemical Reactions Grading Rubric Name Team Name CHM101 Lab Chemical Reactions Grading Rubric To participate in this lab you must have splash- proof goggles, proper shoes and attire. Criteria Points possible Points earned Lab Performance

More information

2 (aq) [FeSCN [Fe 3JSCN] Figure 1

2 (aq) [FeSCN [Fe 3JSCN] Figure 1 The Determination of an Equilibrium Constant Computer Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium constant,

More information

Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.9.13

Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.9.13 Determination of an Equilibrium Constant Minneapolis Community and Technical College Principles of Chemistry II, C1152 v.9.13 I. Introduction Equilibrium Consider the following situation: It is rush hour

More information

EXPERIMENT 5: PHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT

EXPERIMENT 5: PHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT EXPERIMENT 5: PHOTOMETRIC DETERMINATION OF AN EQUILIBRIUM CONSTANT The following preparatory questions should be answered before coming to class. They are intended to introduce you to several ideas important

More information

EXPERIMENT 6: Photometric Determination of an Equilibrium Constant

EXPERIMENT 6: Photometric Determination of an Equilibrium Constant EXPERIMENT 6: Photometric Determination of an Equilibrium Constant The following preparatory questions should be answered before coming to class. They are intended to introduce you to several ideas important

More information

Exp. 20: Spectrophotometric Analysis: Determination of the Equilibrium Constant for a Reaction

Exp. 20: Spectrophotometric Analysis: Determination of the Equilibrium Constant for a Reaction Exp. 20 - video (time: 41:13 minutes) Exp. 20: Spectrophotometric Analysis: Determination of the Equilibrium Constant for a Reaction Chemical Equilibrium Previously we have assumed that chemical reactions

More information

Introduction to Spectroscopy: Analysis of Copper Ore

Introduction to Spectroscopy: Analysis of Copper Ore Introduction to Spectroscopy: Analysis of Copper Ore Introduction The goal of this lab is to determine the unknown concentration of two different copper solution samples, taken from fictitious mining sites

More information

Experiment 11 Beer s Law

Experiment 11 Beer s Law Experiment 11 Beer s Law OUTCOMES After completing this experiment, the student should be able to: determine the wavelength (color) of maximum absorbance for a solution. examine the relationship between

More information

Experiment 11 Beer s Law

Experiment 11 Beer s Law Experiment 11 Beer s Law OUTCOMES After completing this experiment, the student should be able to: determine the wavelength (color) of maximum absorbance for a solution. examine the relationship between

More information

Introduction to Spectroscopy: Analysis of Copper Ore

Introduction to Spectroscopy: Analysis of Copper Ore Introduction to Spectroscopy: Analysis of Copper Ore Using a Buret and Volumetric Flask: 2.06 ml of solution delivered 2.47 ml of solution delivered 50.00 ml Volumetric Flask Reading a buret: Burets are

More information

Determination of an Equilibrium Constant

Determination of an Equilibrium Constant Last updated 1/29/2014 - GES Learning Objectives Students will be able to: Determine the numerical value of an equilibrium constant from measured concentrations of all reaction species. Use an absorption

More information

EXPERIMENT #3 A Beer's Law Study

EXPERIMENT #3 A Beer's Law Study OBJECTVES: EXPERMENT #3 A Beer's Law Study To operate a Spectronic 20 To convert from percent transmission to absorbance units To plot absorbance versus wavelength and find max To plot absorbance versus

More information

Experiment #4. Molar Mass by Freezing Point Depression

Experiment #4. Molar Mass by Freezing Point Depression Experiment #4. Molar Mass by Freezing Point Depression Introduction When a nonvolatile solute is dissolved in a solvent, the freezing point of the solution is lowered. This process is called Freezing Point

More information

Experiment#1 Beer s Law: Absorption Spectroscopy of Cobalt(II)

Experiment#1 Beer s Law: Absorption Spectroscopy of Cobalt(II) : Absorption Spectroscopy of Cobalt(II) OBJECTIVES In successfully completing this lab you will: prepare a stock solution using a volumetric flask; use a UV/Visible spectrometer to measure an absorption

More information

Introduction to Spectroscopy: Analysis of Copper Ore

Introduction to Spectroscopy: Analysis of Copper Ore Absorbance Introduction to Spectroscopy: Analysis of Copper Ore Introduction The goal of this lab is to determine the unknown concentration of two different copper solution samples, taken from fictitious

More information

Solubility Product Constants

Solubility Product Constants Solubility Product Constants PURPOSE To measure the solubility product constant (K sp ) of copper (II) iodate, Cu(IO 3 ) 2. GOALS To measure the molar solubility of a sparingly soluble salt in water. To

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

MORE LIGHTS, COLOR, ABSORPTION!

MORE LIGHTS, COLOR, ABSORPTION! Name Partner(s) Section Date MORE LIGHTS, COLOR, ABSORPTION! PRE-LAB QUERIES 1. The terms absorption and transmittance are often used when describing the interaction of light with matter. Explain what

More information

Introduction to Spectroscopy: Analysis of Copper Ore

Introduction to Spectroscopy: Analysis of Copper Ore Introduction to Spectroscopy: Analysis of Copper Ore Thousands of years ago, copper was abundant enough in quantity that it could be found on the Earth s surface. Prospecting for copper then was relatively

More information

REVIEW OF LAB TECHNIQUES

REVIEW OF LAB TECHNIQUES Experiment 1 REVIEW OF LAB TECHNIQUES Prepared by Masanobu M. Yamauchi and Ross S. Nord, Eastern Michigan University PURPOSE To review density calculations, Beer s Law and the use of electronic balances,

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

Reaction mixtures that have reached equilibrium are represted by chemical equaitions with a doubleheaded

Reaction mixtures that have reached equilibrium are represted by chemical equaitions with a doubleheaded EXPERIMENT 24 LeChatelier s Principle INTRODUCTION Chemical reactions in which a product is essentially unionized, is given off as a gas, or is precipitated, may be thought of as running to completion.

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

Spectrophotometry Materials

Spectrophotometry Materials Spectrophotometry Materials Item per Class per Bench Genesys 10UV Spectrophotometer 6 1 13 ml test tubes box 7 Test tube racks 6 1 1% Albumin solution 25 ml/one flask 2 ml 0.7% Albumin solution (unknown

More information

For simplicity, we ll represent BTB s ionization in a solution by the equilibrium: HBTB = H + + BTB -

For simplicity, we ll represent BTB s ionization in a solution by the equilibrium: HBTB = H + + BTB - Chemistry 160 Please have the following pages ready before class on Wednesday, April 11. An abstract (see the end of this handout) is needed for this write-up. The abstract and photocopied pages of the

More information

Introduction to Spectroscopy: Analysis of Copper Ore

Introduction to Spectroscopy: Analysis of Copper Ore Introduction to Spectroscopy: Analysis of Copper Ore Using a Buret and Volumetric Flask: 2.06 ml of solution 2.47 ml of solution 50.00 ml delivered delivered Volumetric Flask Reading a buret: Burets are

More information

Rate law Determination of the Crystal Violet Reaction Using the Isolation Method

Rate law Determination of the Crystal Violet Reaction Using the Isolation Method Rate law Determination of the Crystal Violet Reaction Using the Isolation Method Introduction A common challenge in chemical kinetics is to determine the rate law for a reaction with multiple reactants.

More information

Making Measurements. Units of Length

Making Measurements. Units of Length Experiment #2. Measurements and Conversions. Goals 1. To measure and record length, volume and mass accurately with the correct number of significant figures 2. To convert between units using conversion

More information

11. Introduction to Acids, Bases, ph, and Buffers

11. Introduction to Acids, Bases, ph, and Buffers 11. Introduction to Acids, Bases, ph, and Buffers What you will accomplish in this experiment You ll use an acid-base indicating paper to: Determine the acidity or basicity of some common household substances

More information

UNIT 3: CHEMICAL EQUILIBRIUM (TEXT: Chap 14-pg 627 & Chap 18 pg )

UNIT 3: CHEMICAL EQUILIBRIUM (TEXT: Chap 14-pg 627 & Chap 18 pg ) UNIT 3: CHEMICAL EQUILIBRIUM (TEXT: Chap 14-pg 627 & Chap 18 pg 818-829) *Remedial questions on Concentration of Solutions (3.10 pg 130-135) 3:1. ATTEMPT QUESTIONS a) 3.109 b) 3.113 c) 3.115 d) 3.118 on

More information

Exp 03 - Reaction Rate

Exp 03 - Reaction Rate GENERAL CHEMISTRY II CAÑADA COLLEGE SUMMER 2018 Exp 03 - Reaction Rate How the speed at which quantities change during a chemical reaction can be measured, predicted and used to understand the mechanism

More information

Chemistry 1215 Experiment #11 Spectrophotometric Analysis of an Unknown Brass Sample

Chemistry 1215 Experiment #11 Spectrophotometric Analysis of an Unknown Brass Sample Chemistry 1215 Experiment #11 Spectrophotometric Analysis of an Unknown Brass Sample Objective In this experiment you will use spectrophotometric measurements to determine the copper concentration of a

More information

MOHAWK COLLEGE OF APPLIED ARTS AND TECHNOLOGY CHEMICAL AND ENVIRONMENTAL TECHNOLOGY DEPARTMENT. Lab Report ROOM NO: FE E309

MOHAWK COLLEGE OF APPLIED ARTS AND TECHNOLOGY CHEMICAL AND ENVIRONMENTAL TECHNOLOGY DEPARTMENT. Lab Report ROOM NO: FE E309 MOHAWK COLLEGE OF APPLIED ARTS AND TECHNOLOGY CHEMICAL AND ENVIRONMENTAL TECHNOLOGY DEPARTMENT Lab Report ROOM NO: FE E309 EXPERIMENT NO : 4 TITLE : UV Spectrophotometric Analysis of DNA Submitted by Class

More information

Aqueous Balance: Equilibrium

Aqueous Balance: Equilibrium Activity 4 Aqueous Balance: Equilibrium GOALS In this activity you will: Determine ph and understand its meaning. Learn the basic principles behind equilibrium and the law of mass action. Calculate a solubility

More information

CHM101 Lab Measurements and Conversions Grading Rubric

CHM101 Lab Measurements and Conversions Grading Rubric CHM101 Lab Measurements and Conversions Grading Rubric Name Team Name Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Safety and proper waste

More information

Determining the Concentration of a Solution: Beer s Law

Determining the Concentration of a Solution: Beer s Law Determining the Concentration of a Solution: Beer s Law The primary objective of this experiment is to determine the concentration of an unknown cobalt (II) chloride solution. You will use a Vernier SpectroVis

More information

MEASUREMENT: PART II

MEASUREMENT: PART II 1 MEASUREMENT: PART II Copyright: Department of Chemistry, University of Idaho, Moscow, ID 83844-2343, 2013. INTRODUCTION Read and/or review Section 1.7 and Figure 7.5 in your textbook. The first part

More information

Introduction to Strong and Weak Acids

Introduction to Strong and Weak Acids Introduction to Strong and Weak Acids Please review the techniques for pipetting a solution, using a buret and performing a titration. There is a link on the 152LL page next to the activity. Introduction:

More information