Abeka Chemistry Chapter 15

What is a salt?

an ionic compound composed of any cation except H⁺ and any anion except OH⁻ (or an ionic compound containing the cation of an aqueous base and the anion of an aqueous acid)

Name the following compound as an acid. H₂CrO₄

chromic acid

Determine the pH of the following solution 0.025 M LiOH

12.40

Determine the pH of the following solution 3.5 x 10⁻³ M HCl

2.46

Write a balanced equation for the reaction of the following solid with Hydrochloric acid; if no reaction will occur write "no reaction." Al

2Al(s) + 6HCl→2AlCl₃ + 3H₂(g)

Write a balanced equation for the reaction of the following solid with Hydrochloric acid; if no reaction will occur write "no reaction." Na₂CO₃

2HCl(aq) + Na₂CO₃(s)→2NaCl(aq) + CO₂(g) + H₂O(l)

At what pH is a substance considered neutral?

7 (at 25°C)

Why are solutions of some salts acidic or basic instead of neutral?

A reaction occurs between the water molecules and an ion in the salt to produce OH⁻ or H₃O⁺ ions.

Differentiate between a strong acid and a weak one.

A strong acid ionizes essentially completely in aqueous solution to form H₃O⁺, whereas a weak acid ionizes incompletely in aqueous solution.

How does the normality of an acid solution relate to the equivalent mass of the acid?

Answer will vary; because the normality of a solution equals the equi8valents of solute per liter of solution, a solution containing 1 equivalent mass of an acid will be a 1 N solution.

Differentiate between the Arrhenius and Brønsted-Lowry definition of an acid.

Answers will vary. According to the Arrhenius definition, an acid is any substance that produces H⁺ (or H₃O⁺) ions when dissolved in water. According to the Brønsted-Lowry definition, an acid is any substance that can donate a proton (H⁺) to another substance; water is not required.

Give one important example of a use of a buffer.

Answers will vary. One example is the buffers in the blood, which work to prevent fatal changes in blood pH.

Write the net ionic equation for the following reaction: Ba(s) + 2HCl(aq)→→BaCl₂(aq) + H₂(g)

Ba(s) + 2H⁺(aq)→Ba²⁺(aq) + H₂(g)

Write a formula for the conjugate base of the following acid: HCN

CN⁻

Write the net ionic equation for the following reaction. (balance the equation as needed) Na₂CO₃(aq) + CaCl₂ (aq)→CaCO₃(s)+NaCl(aq)

CO₃²⁻(aq) + Ca²⁺(aq)→CaCO₃(s)

Write a formula for the conjugate base of the following acid: HClO₄

ClO₄⁻

Write a formula for the conjugate acid of the following base: C₂H₃O₂⁻

HC₂H₃O₂

Write the net ionic equation for the following reaction. (balance the equation as needed) HF(aq)+KOH (aq)→H₂O(l) + KF(aq)

HF(aq) + OH⁻(aq)→H₂O(l) + F⁻(aq)

Write the net ionic equation for the following reaction: HCl(aq) + NaOH(aq)→→NaCl(aq) + H₂O(l)

H⁺(aq) + OH⁻(aq)→H₂O(l)

Write a formula for the conjugate acid of the following base: HPO₄²⁻

H₂PO₄⁻

Write a formula for the conjugate acid of the following base: HSO₄⁻

H₂SO₄

In what form do protons generally exist in aqueous solutions?

H₃O⁺ (hydronium ion)

How are the pH and pOH scales related?

In any aqueous solution at 25°C, the sum of the pH and pOH is 14.

Write the net ionic equation for the following reaction. (balance the equation as needed) NH₃(g) + HCl (aq)→NH₄Cl(aq)

NH₃(g) + H⁺(aq)→NH₄⁺(aq)

Write a formula for the conjugate acid of the following base: NH₃

NH₄⁺

Write a formula for the conjugate base of the following acid: H₂O

OH⁻

Write a formula for the conjugate base of the following acid: HPO₄²⁻

PO₄³⁻

Identify the Brønsted-Lowry acid, base, and conjugate acid-base pairs in the following reaction H₂PO₄⁻(aq)+ HSO₄⁻(aq)⇌H₃PO₄ (aq)+ SO₄²⁻ (aq)

Pg 251 application #1 letter a

Identify the Brønsted-Lowry acid, base, and conjugate acid-base pairs in the following reaction S²⁻(aq)+ H₂O(l)⇌HS⁻(aq) + OH⁻(aq)

Pg 251 application #1 letter b

Write a formula for the conjugate acid of the following base: NH₃

Pg 267 chapter review problem #1 letter a

Write a formula for the conjugate acid of the following base: HSO₄⁻

Pg 267 chapter review problem #1 letter b

Write a formula for the conjugate acid of the following base: HPO₄²⁻

Pg 267 chapter review problem #1 letter c

Write a formula for the conjugate acid of the following base: C₂H₃O₂⁻

Pg 267 chapter review problem #1 letter d

In a laboratory titration, 18.74mL of an HCl solution was neutralized by 27.08 mL of 0.0750 N NaOH. Calculate the normality and molarity of the original HCl solution.

Pg 267 chapter review problem #7

Use Le Chatelier's principle to explain how a buffer resists changes in pH.

Pg 267 chapter review question #14

Write the net ionic equation for the following reaction: K₂S(aq) + 2AgNO₃(aq)→→Ag₂S(s) + 2KNO₃(aq)

S²⁻(aq) + 2Ag⁺(aq)→Ag₂S(s)

In your own words, explain why a 1 M HCl solution and a 1N HCl solution have the same concentration, but a 1 M HCl solution and a one N H₂SO₄ solution do not.

The HCl solutions are both monoprotic acids; therfore M = N. The HCl and H₂SO₄ solutions have different molarity and normality because HCl is monoprotic and H₂SO₄ is diprotic; for diprotic acids, N = 2 x M.

How do the relative concentraions of H₃O⁺ and OH⁻ compare in pure water?

They are equal.

What is pH? Name two ways pH can be measured in the laboratory.

a measure of the H₃O⁺ molar concentration of a substance, mathematically defined as -log [H₃O⁺]; pH meter, acid-base indicators, universal indicator, pH paper

What is the pH scale?

a measure of the concentration of H₃O⁺ ions in a given solution

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral NH₄NO₃

acidic

Tell whether the following solution is acidic, basic, or neutral. [H₃O⁺]= 9.1 x 10 ⁻⁶

acidic

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral KC₂H₃O₂

basic

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral LiF

basic

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral Na₃PO₄

basic

Tell whether the following solution is acidic, basic, or neutral. [OH⁻]= 9.1 x 10⁻²

basic

Name the following compound as an acid. H₃BO₃ (BO₃³⁻ is borate)

boric acid

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral (NH₄)₂CO₃

cannot be determined based on text guidelines

Name the following compound as an acid: HCHO₂ (CHO₂⁻ is formate)

formic acid

Name the following compound as an acid: HI

hydroiodic acid

Name the following compound as an acid: H₂Se

hydroselenic acid

Name the following compound as an acid. H₂S

hydrosulfuric acid

Name the following compound as an acid. H₂Te

hydrotelluric acid

Name the following compound as an acid: HClO (ClO⁻ is hypochlorite)

hypochlorous acid

Name the following compound as an acid: H₃PO₂ (PO₂³⁻ is hypophosphate)

hypophosphoric acid

Name the following compound as an acid: HIO₃ (IO₃⁻ is iodate)

iodic acid

What is the constant K(sub w) called? WHat is its value at 25°C?

ion-product constant of water; 1.00 x 10⁻¹⁴

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral BaCl₂

neutral

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral CaI₂

neutral

Tell whether aqueous solutions of the following salt is acidic, basic, or neutral K₂SO₄

neutral

Tell whether the following solution is acidic, basic, or neutral. [H₃O⁺] = 1.0 x 10⁻⁷

neutral

WHat term refers to a reaction between an acid and a base to form a salt and water?

neutralization

Write a balanced equation for the reaction of the following solid with Hydrochloric acid; if no reaction will occur write "no reaction." Ag

no reaction

Name the following compound as an acid. H₂C₂O₄ (C₂O₄²⁻ is oxalate)

oxalic acid

tell the direction of equilibrium for the following (use table 15.5) HClO₄(aq)+OH⁻(aq)⇌H₂O(l)+ClO₄⁻(aq)

right

tell the direction of equilibrium for the following (use table 15.5) NH₃(aq)+HSO₄⁻ (aq)⇌SO₄²⁻(aq) +NH₄⁺(aq)

right

Name the following compound as an acid: H₄SiO₄ (SiO₄⁻ is silicate)

silicic acid

List the types of substances that are written in ionic form in an ionic equation.

soluble salts, strong acids, strong bases

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). BaCl₂

strong base--strong acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). CaI₂

strong base--strong acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). K₂SO₄

strong base--strong acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). KC₂H₃O₂

strong base--weak acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). LiF

strong base--weak acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). Na₃PO₄

strong base--weak acid

Name the following compound as an acid. H₂SO₄

sulfuric acid

What is meant by neutralization?

the reaction between an acid and a base to form a salt and water

What is the function of a buffer?

to maintain a relatively constant pH by reacting with added acid or base

List the types of substances that are written in molecular form in an ionic equation.

weak acids, weak bases, soluble molecular substances, water-insoluble substances

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). NH₄NO₃

weak base--strong acid

Classify the following salt according to the type of acid or base from which it is considered to be derived (e.g. strong base- weak acid). (NH₄)₂CO₃

weak base--weak acid

Distinguish between the Arrhenius and Brønsted-Lowry definitions of acids and bases. Which includes a wider range of substances?

∙By the Arrhenius definition, an acid is a substance that produces H⁺ when dissolved in water and a base is a substance that produces OH⁻ when dissolved in water. by the Brønsted-Lowry definition, an acid is a substance that can donate a proton to another substance, and a base is a substance that can accpet a proton from some other substance. ∙The Brønsted-Lowry definition includes a wider range of substances.

What is an acidic anhydride? A basic anhydride?

∙acidic anyhdride-nonmetal oxide that forms an acid when it reacts with water ∙basic anhydride-metal oxide that forms a basic solution when it reacts with water

List three properties of acids and three of bases.

∙acids-sour taste; react with metals such as zinc to produce H₂; change blue litmus to red ∙bases-bitter taste and slippery feel; react with acids to neutralize them; change red litmus to blue