Quiz 1,2,3

The [OH-] and the pH of 0.035 M KOH at 25°C are, respectively, 2.9 × 10-13 M and +12.54. 0.035 and +12.54. 0.035 M and +1.46. 0.035 M and -1.46. 2.9 × 10-13 M and -12.54.

0.035 and +12.54.

Which of these, if dissolved in 1.0 L of pure water, would produce a buffer solution? 0.1 mol H3O+ + 0.1 mol Cl- 0.1 mol HCl + 0.1 mol NaOH 0.1 mol NaH2PO4 + 0.1 mol Na2HPO4 0.1 mol H3O+ + 0.1 OH- 0.1 mol NaCl + 0.1 mol KCl

0.1 mol NaH2PO4 + 0.1 mol Na2HPO4

If the concentration of OH- is 1 × 10-2 M, the concentration of H3O+ is ________ M. 1 × 10^-2 1 × 10^-14 1 × 10^-7 1 × 10-^12 1 × 100^0

1 × 10-^12

Calculate the normality of a solution made by diluting 12 g of H3PO4 with water to produce 250.0 mL of solution. 1.5 N 0.49 N 0.048 N 0.16 N

1.5 N Correct Normality = molarity*(equivalents/mol) (3 H+ ions per formula unit).

What is the value of [H3O+] in a solution with pH = 10.82? 3.18 M 1.5 × 10-11 M 6.6 × 10-4 M 1.03 M 10.82 M

1.5 × 10-11 M

Which of the following pH's corresponds to a strongly basic solution? 4.3 6.9 7.4 2.7 11.5

11.5

Write and balance the following acid-base neutralization reaction:HBr(aq) + Li2CO3(aq) → HBr(aq) + Li2CO3(aq) →→ 2 LiBr(aq) + H2CO3(l) 4 HBr(aq) + Li2CO3(aq) →→ 2 LiBr2(aq) + 2 H2O(l) + CO2(g) HBr(aq) + Li2CO3(aq) →→ LiBr(aq) + H2O(l) + CO2(g) 2 HBr(aq) + Li2CO3(aq) →→ 2 LiBr(aq) + H2O(l) + CO2(g)

2 HBr(aq) + Li2CO3(aq) →→ 2 LiBr(aq) + H2O(l) + CO2(g)

What is the normality of a solution containing 49 g of H2SO4 in enough water to make 400 mL of solution? 5.0 N 2.5 N 0.20 N 10 N 1.0 N

2.5 N

How many mL of 0.100 M NaOH are needed to neutralize 24.0 mL of 0.150 M HCl? 24.0 mL 48.0 mL 12.0 mL 18.0 mL 36.0 mL

36.0 mL

How many mL of 1.50 M HCl are needed to titrate 25.0 mL of 1.20 M Ca(OH)2? 62.5 mL 10.0 mL 20.0 mL 40.0 mL

40.0 mL Correct Using Nbase = 2.40 Eq/L, Vacid = (Nbase × Vbase) / Nacid.

The normality of a solution prepared by dissolving 50.0 g of Ca(OH)2 in water to make 250. mL solution is ________ N. 7.02 5.40 3.51 2.70 1.35

5.40

What is the [H3O+] of a solution with pOH = 3.75? 1.8 x 10^-4 M 5.6 x 10^-7 M 5.623 x 10^-11 M 5.6 x 10^-11 M

5.6 x 10^-11 M Correct pH + pOH = 14 and [H3O+] = 10−pH.

Which of the following pH's corresponds to a neutral solution? 8.5 7.0 6.2 14.0 1.8

7.0

The pH of a 250. mL sample of a buffer solution is 9.85. If 1.0 mL of 6 M HCl is added, the pH of the resulting mixture is closest to 9.70. 7.00. 1.65. 10.00. 0.00.

9.70

Explain the term "amphoteric." An amphoteric compound or ion is one that can behave either as an acid or a base in solution, depending on the chemical environment. An amphoteric compound is one that behaves as an acid in the acid or base solutions. An amphoteric compound is one that behaves as a base in the acid or base solutions. An amphoteric compound is one that lacks the long-range order characteristic of a crystal.

An amphoteric compound or ion is one that can behave either as an acid or a base in solution, depending on the chemical environment.

Which of the following species can only act as a Brønsted-Lowry base, but not a Brønsted-Lowry acid? CN- NH3 HCO3- H2O

CN- Correct CN− can accept H+ and turn into weak acid HCN, but it cannot donate H+, as it does not have any.

Which reaction best illustrates the behavior of the weak base H2PO4- in aqueous solution? H2PO4- (aq) ↔ 2H+ (aq) + PO43- (aq) H2PO4- (aq) ↔ H+ (aq) + HPO42- (aq) H2PO4- (aq) + H2O (l) ↔ H3PO4 (aq) + OH- (aq) H2PO4- (aq) + H2O (l) ↔ HPO42- (aq) + H3O+ (aq) H2PO4- (aq) + H+ (aq) ↔ H3PO4 (aq)

H2PO4- (aq) + H2O (l) ↔ H3PO4 (aq) + OH- (aq)

What is the conjugate acid of water? H2O (l) O2- (aq) H3O+ (aq) OH- (aq) H+ (aq)

H3O+ (aq)

Which of the following represents a conjugate acid/base pair? H3O+/H2O HClO4/HClO3 NH4 +/NH2 − H2SO4/SO4 2−

H3O+/H2O Correct Adding one H+ to H2O would produce H3O+.

According to the K a values in Table 10.3, which of the following is the weakest acid? HCN H2SO4 HF H2CO3

HCN Correct The smallest K a indicates the weakest acid.

Which of the following reactions would result in the formation of a gaseous product? NH3 + HNO3 → KHCO3 + HBr → NaOH + HCl → Ca(OH)2 + H3PO4 →

KHCO3 + HBr → Correct The double replacement reaction will yield unstable H2CO3, which will then decompose into water and CO2 gas.

Which of the following compounds is a base? H2O NH3 C2H5OH HCl

NH3

Which compound produces an acidic solution when dissolved in water? NH4Cl KCl Ca(NO3)2 NaF K2SO4

NH4Cl

Which of the following acids would be the best choice in making a buffer solution with pH = 5.00? H2SO4 Propanoic acid, K a = 1.3 × 10−5. H3PO4, K a = 7.5 × 10−3. HCN, K a = 4.9 × 10−10.

Propanoic acid, K a = 1.3 × 10−5. pKa = 4.89—very close to the desired value.

Sulfuric acid (H2SO4) is a strong acid. Which of the following statements correctly describes its conjugate base? The conjugate base, HSO4 −, is a strong base. The conjugate base, H3O+, is a weak base. The conjugate base, SO4 2−, is a weak base. The conjugate base, HSO4 −, will have little to no reaction as a base, but it can react as an acid.

The conjugate base, HSO4 −, will have little to no reaction as a base, but it can react as an acid. Correct Strong acids will have weak conjugate bases, and vice versa.

What is the correct Ka expression for the reaction below?CH3COOH(aq) + H2O(l) ⇌⇌ CH3COO-(aq) + H3O+(aq) [CH3COO−][H3O+] [CH3COOH][H2O] [CH3COO−] [CH3COOH] [CH3COO−][H3O+] [CH3COOH] [CH3COOH] [CH3COO−][H3O+] [CH3COOH][H2O] [CH3COO−][H3O+]

[CH3COO−][H3O+][CH3COOH]

A Brønsted-Lowry acid is a substance which produces hydrogen ions in aqueous solution. accepts protons from other substances. accepts hydronium ions from other substances. donates protons to other substances. produces hydroxide ions in aqueous solution.

donates protons to other substances.

What is the conjugate base of water? H+ (aq) H2O (l) OH- (aq) O2- (aq) H3O+ (aq)

oH- (aq)

When potassium hydroxide and hydrobromic acid are combined the products are potassium bromite and hydrogen gas. potassium bromide and hydrogen gas. potasium bromate and water. potassium hypobromite and water. potassium bromide and water.

potassium bromide and water.

A reaction between an acid and base—a neutralization reaction—always results in the formation of ____________. water and a salt an acid and a base water, salt, and carbon dioxide gas No reaction

water and a salt Correct An acid plus a base will result in the formation of neutral water plus a salt.