Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Acids and Bases Chemistry Concepts Worksheet with Key, Exercises of Chemistry

CK-12 level acid base chapter problems with solutions

Typology: Exercises

2020/2021

Uploaded on 03/30/2021

larryp
larryp 🇺🇸

4.8

(34)

353 documents

1 / 17

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1
CK-12 Chemistry Concepts - Intermediate
Answer Key
Chapter 21: Acids & Bases
21.1 Properties of Acids
Practice
Questions
1. Which of the four solutions are acids?
2. Stop the video at 0:30 minutes and predict conductivities.
3. What color did the acids turn when universal indicator was added?
Answers
1. HCl and CH3COOH (acetic acid).
2. The acids and NaCl are ionized and will conduct electricity.
3. Red.
Review
Questions
1. Are all acids electrolytes in water?
2. What color does blue litmus turn in the presence of an acid?
3. What does the reaction of an acid and a base produce?
Answers
1. Yes.
2. Red.
3. Water and a salt.
21.2 Properties of Bases
Practice
Questions
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff

Partial preview of the text

Download Acids and Bases Chemistry Concepts Worksheet with Key and more Exercises Chemistry in PDF only on Docsity!

CK-12 Chemistry Concepts - Intermediate

Answer Key

Chapter 21: Acids & Bases

21.1 Properties of Acids

Practice

Questions

  1. Which of the four solutions are acids?
  2. Stop the video at 0:30 minutes and predict conductivities.
  3. What color did the acids turn when universal indicator was added?

Answers

  1. HCl and CH 3 COOH (acetic acid).
  2. The acids and NaCl are ionized and will conduct electricity.
  3. Red.

Review

Questions

  1. Are all acids electrolytes in water?
  2. What color does blue litmus turn in the presence of an acid?
  3. What does the reaction of an acid and a base produce?

Answers

  1. Yes.
  2. Red.
  3. Water and a salt.

21.2 Properties of Bases

Practice

Questions

  1. What does the reaction between an acid and a base produce?
  2. What is this reaction called?
  3. What does the reaction of a base with an ammonium salt form?

Answers

  1. A salt and water.
  2. Neutralization.
  3. A metal salt, ammonia, and water.

Review

Questions

  1. Are bases electrolytes?
  2. What color does a base turn phenolphthalein?
  3. Do bases react with metals the same way that acids do?

Answers

  1. Yes, some are strong electrolytes and some are weak.
  2. Red.
  3. No.

21.3 Arrhenius Acids

Practice

  1. What was Arrhenius’ first scientific idea?
  2. What did his Ph.D committee think about it?
  3. What did he win for this idea?
  4. Write the generic equation for dissociation of an Arrhenius acid.

Answers

  1. Electrolytes dissociated in solution.
  2. They did not like it and gave him a D for his research.

21.5 Bronsted-Lowry Acids and Bases

Practice

Questions

  1. Why is water considered a base in the reaction between water and HCl?
  2. Why is H 3 O+^ considered an acid?
  3. Why is the chloride anion considered a base?

Answers

  1. Because it can accept a proton from the HCl to form the hydronium ion.
  2. Because it can donate a proton.
  3. Because it can accept a proton to form HCl.

Review

Questions

  1. What is a Brønsted-Lowry acid?
  2. What is a Brønsted-Lowry base?
  3. How does ammonia function as a Brønsted-Lowry base?

Answers

  1. A molecule or ion that donates a proton.
  2. A molecule or ion that accepts a proton.
  3. The lone pair electrons on the N atom can accept a proton.

21.6 Bronsted-Lowry Acid-Base Reactions

Practice

Questions

Questions

  1. In the reaction between ammonia and water, how does the ammonia serve as a base on the left-hand side of the equation?
  2. How does the ammonium ion serve as an acid on the right-hand side of the equation?
  3. Write the conjugate acid-base pairs for the reaction between two water molecules illustrated above.

Answers

  1. It accepts a proton.
  2. It donates a proton.
  3. H 2 O/H 3 O+^ and OH -^ /H 2 O.

21.7 Lewis Acids and Bases

Practice

Questions

  1. What is the difference between a Lewis acid or base and a Brønsted Lowry acid or base?
  2. What is required to happen in Lewis acid-base reactions?
  3. Do all Lewis acid-base reactions involve protons?

Answers

  1. What is a buffer?
  2. How much more acidic is vinegar than grapefruit?
  3. How much more basic is soapy water than milk of magnesia?

Answers

  1. A solution that resists pH changes when acid or base or added.
  2. Ten times more acidic.
  3. One hundred times more basic.

Review

Questions

  1. What is one value of using pH instead of molar concentrations?
  2. Is coffee an acidic or a basic substance?
  3. If a material has a pH of 9.3, is it acidic or basic?

Answers

  1. A simple number can be used instead of an exponential expression.
  2. Acidic.
  3. Basic.

21.10 Calculating pH of Acids and Bases

Practice

Questions

  1. What is the pH of a 4.5 x 10-3^ M HI solution?
  1. What is the pH of a 3.67 x 10 -5^ M NaBr solution?
  2. If we have a weak base with a low ionization constant, can we assume that the [OH -^ ] in the solution is equal to the concentration of the base?

Answers

  1. pH = 2.4.
  2. pH = 9.56.
  3. No, the hydroxide ion concentration will not be equal to the molar concentration of the base because all the OH -^ will not be in the dissociated form.

21.11 The pOH Concept

Practice

Questions

  1. What is the formula for calculating pOH?
  2. What pOH value is indicative of an acidic solution?
  3. A pOH value of 3 would indicate what type of solution?

Answers

  1. pOH = -log[OH-]
  2. A value of less than 7.
  3. A basic solution.

21.12 Strong and Weak Acids and Acid Ionization Constant (Ka)

Practice

Questions

  1. The further the equilibrium is to the left, the weaker the base.

Review

Questions

  1. Define a strong base.
  2. Define a weak base.
  3. Which is the stronger base: pyridine or urea?

Answers

  1. A base which ionizes completely in an aqueous solution.
  2. A base that ionizes only a small amount in an aqueous solution.
  3. Pyridine.

21.14 Calculating Ka and Kb

Practice

Questions

  1. What does an Arrhenius base dissociate to?
  2. What does a Brønsted-Lowry base form in water?
  3. How is percent ionization determined?

Answers

  1. The cation of the base plus OH -^.
  2. The base reacts with water. The products are the protonated base plus a hydroxide ion.
  3. % dissociation (ionization) = [OH -^ at equilibrium] ÷ [base initial] x 100.

Review

Questions

  1. What approach is used for calculation of ionization constants?
  2. What initial assumptions are made?
  3. What equilibrium assumptions are made?

Answers

  1. The ICE approach.
  2. The concentrations of H +^ and base anion are zero.
  3. The concentrations of H +^ and base anion are equal.

21.15 Calculating pH of Weak Acid and Base Solutions

Practice

Questions

  1. What does x stand for in the equation?
  2. What simplifying assumption is made?
  3. What would x stand for if we were calculating pOH?

Answers

  1. The hydrogen ion concentration.
  2. The extent of ionization of a weak acid is small and x in the denominator can be ignored.
  3. Concentration of the hydroxide ion.

21.16 Neutralization Reaction and Net Ionic Equations for Neutralization Reactions

Practice

Review

Questions

  1. What is the standard solution?
  2. How do you know you have reached the end-point?
  3. What is the reaction that occurs during a titration?

Answers

  1. A known concentration of sodium hydroxide.
  2. The phenolphthalein turns pink.
  3. A neutralization reaction: acid + base → salt + water.

21.18 Titration Calculations

Practice

Questions

  1. What assumption is made about the amounts of materials at the neutral point?
  2. What is different about the calculation using sulfuric acid?
  3. Why is the mole ratio important?

Answers

  1. The moles of acid equal the moles of base.
  2. There are two protons to neutralize in a molecule of sulfuric acid.
  3. We need to know how many moles of acid are involved in the reaction.

21.19 Titration Curves

Practice

Questions

  1. Why is the equivalence point less than pH 7 for the titration of ammonia with HCl?
  2. Why is it difficult to do a titration of a weak acid and a weak base?
  3. Why do we get two inflection points for the titration of ethanedioic acid?

Answers

  1. Some of the product formed is ammonium chloride, which can dissociate into ammonia and a proton.
  2. There is no steep break in the curve to indicate where the equivalence point is.
  3. There are two different acid dissociation constants.

Review

Questions

  1. What does a titration curve tell us?
  2. At what pH are the moles of acid and base equal?
  3. Is the equivalence point for a weak acid-strong base titration the same as for a strong-acid-strong base titration?

Answers

  1. The change in pH as base is added.
  2. pH 7.
  3. No, the pH is greater than 7.

21.20 Indicators

Practice

Questions

  1. What was the acid used.
  2. What was the base used?
  3. What color was methyl orange in acid? in base?

Answers

  1. It reacts somewhat with water to form HF and OH -^.
  2. It releases a proton when it forms ammonia.
  3. There are no acid-base equilibrium reactions occurring.

21.22 Calculating pH of Salt Solutions

Practice

Questions

  1. In the first example, how do we know that we can ignore x when determining [F-]?
  2. In example two, how do we know the ammonium ion concentration?
  3. Could we write the equilibrium in example two as NH 4 +

⇌ H+^ + NH 3?

Answers

  1. The K (^) b is very small.
  2. Ammonium chloride dissociated completely in water.
  3. Yes, this equation is functionally equivalent to the more complete one.

21.23 Buffers

Practice

Questions

  1. What is a weak acid?
  2. What does a conjugate base rarely do?
  3. Write the generic equation for neutralization of a base by a weak acid.
  4. Write the generic equation for neutralization of an acid by a weak base.

Answers

  1. One that rarely loses a proton to water.
  2. It rarely steals a proton from water.
  3. OH -^ + HA → A-^ + H 2 O.
  4. HCl + A -^ → HA + Cl-^.

Review

Questions

  1. What is a buffer?
  2. How would the acetic acid/ acetate buffer system neutralize added base?
  3. If acid is added to the carbonic acid/ carbonate buffer system, how is it neutralized?

Answers

  1. A solution of a weak acid or base and its salt.
  2. Some acetic acid would release protons to neutralize the base.
  3. The carbonate anion would react with the excess acid.