Houston Why the Conjugate Base of A Strong Acid Cant React with Water Worksheet

TVO ILC
SCH4U
Unit 3 Assessment
Unit 3 Assessment for Feedback and Grading
Student name: _____________________________ Date: ___________________
This is an Assessment for feedback and grading, which is used to evaluate your work
based on established criteria and to assign a mark. Your teacher will provide you with
feedback and a mark which is worth 10% of your final grade.
Unit
Level / Mark
Percentage of final grade
3
_______ / 26
_______ / 10%
Instructions:
1. Read each question carefully.
2. Answer each question, showing all your work for any calculations.
3. Answer questions using full sentences unless instructed otherwise
Please answer the following questions in the space provided. Part marks will be awarded for
partial answers. Show all of your work for each calculation.
Curriculum Expectation E3. demonstrate an understanding of the concept of dynamic
equilibrium and the variables that cause shifts in the equilibrium of chemical systems.
1.
You are a chemical engineer that is responsible for synthesizing a new drug. You
look at a series of potential chemical reactions that will make your drug along with
their respective K values. What type of K value would you be looking for and why?
(2 marks)
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TVO ILC
SCH4U
Unit 3 Assessment
2.
Look at the following reaction:
N2O4 (g) + 32.1 kJ
2NO2 (g)
What would you have to do to the reaction in order to increase the magnitude of K?
(1 mark)
3.
If Q < K, which way will the reaction proceed and why? (1 mark)
4.
Explain why the conjugate base of a strong acid can react with water. (2 marks)
Copyright 2020 The Ontario Educational Communications Authority. All rights reserved.
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TVO ILC
SCH4U
Unit 3 Assessment
5.
Why are some salts acidic when others are neutral? (2 marks)
Curriculum Expectation E2. investigate the qualitative and quantitative nature of chemical
systems at equilibrium, and solve related problems.
1.
Consider the following reaction:
PCl3 (g)+ Cl2 (g)
PCl5 (g)
K = 4.30 x 10-6
Initially, 2.50 M PCl3 and 1.40 M Cl2 are placed into a container and allowed to
reach equilibrium. Determine the equilibrium concentrations of all the species.
(3 marks)
Copyright 2020 The Ontario Educational Communications Authority. All rights reserved.
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TVO ILC
SCH4U
Unit 3 Assessment
2.
Would you expect a solution of ammonium chloride (NH4Cl) to be acidic or basic
when added to water? (Kb NH3 = 1.8 x 10-5) (2 marks)
3.
What is the pH of a 1.15 M solution of methanoic acid? Ka = 1.8 x 10-4 (4 marks)
4.
What is the pH of a 0.350 M solution of lithium citrate? (Ka Citric Acid = 7.4 x 10-4)
(4 marks)
Copyright 2020 The Ontario Educational Communications Authority. All rights reserved.
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3
TVO ILC
SCH4U
Unit 3 Assessment
5.
A 50.0 mL solution of 0.150 M acetic acid (CH3COOH) is titrated with 0.150 M NaOH.
What is the pH after 20.0 mL of base has been added? Ka CH3COOH = 1.8 x 10-5
(5 marks)
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