You are given a 200-mL sample of surface water from Lake Ontario, and asked to determine the chemical oxygen demand (COD) of the sample. To do so, you reflux the sample with 15 mL of a 0.2M K,Cr,O, standard solution for 2 hours, then titrate the excess dichromate using 20.0 mL of a 0.3M Fe2 solution. What was the COD of the sample (reported in mol/L of O2)? Reminder: Cr 0,2 consumes 6e", Fe2 offers le". A. The COD of the sample is O.010 mol/L O2 B. The COD of the sample is 0.008 mol/L O2 O C The COD of the sample is 0.015 mol/L O2 O D. The COD of the sample is 0.005 mol/L O2

You are given a 200-mL sample of surface water from Lake Ontario, and asked to determine the chemical oxygen demand (COD) of the sample. To do so, you reflux the sample with 15 mL of a 0.2M K,Cr,O, standard solution for 2 hours, then titrate the excess dichromate using 20.0 mL of a 0.3M Fe2 solution. What was the COD of the sample (reported in mol/L of O2)? Reminder: Cr 0,2 consumes 6e", Fe2 offers le". A. The COD of the sample is O.010 mol/L O2 B. The COD of the sample is 0.008 mol/L O2 O C The COD of the sample is 0.015 mol/L O2 O D. The COD of the sample is 0.005 mol/L O2

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Question

Determining Chemical Oxygen Demand
You are given a 200-mL sample of surface water from Lake Ontario, and asked to determine the
chemical oxygen demand (COD) of the sample. To do so, you reflux the sample with 15 mL of a
0.2M K,Cr,O, standard solution for 2 hours, then titrate the excess dichromate using 20.0 mL of a
0.3M Fe2 solution. What was the COD of the sample (reported in mol/L of O2)?
Reminder: Cr30,2 consumes 6e", Fe2* offers le.
A. The COD of the sample is 0.010 mol/L O2
B. The COD of the sample is 0.o08 mol/L O2
C. The COD of the sample is 0.015 mol/L O2
O D. The COD of the sample is 0.005 mol/L O2.

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