Module 12
The molar solubility of tin(II) iodide is 1.28 × 10⁻² mol/L. What is Ksp for this compound?
8.4 x 10-6
Which of these species has the highest entropy (S°) at 25°C?
A) CO(g)
B) CH₄(g)
C) NaCl(s)
D) H₂O(l)
E) Fe(s)
CH₄(g)
How many coulombs of charge are required to reduce 0.25 mol of Cu²⁺ to Cu?
4.8 × 10⁴ C
Which of the following liquids would have the highest viscosity at 25°C?
A) CH₃OCH₃
B) CH₂Cl₂
C) C₂H₅OH
D) CH₃Br
E) HOCH₂CH₂OH
HOCH₂CH₂OH
The activation energy for the reaction CH₃CHO → CH₄ + CO is 71 kJ/mol.
How many times greater is the rate constant for this reaction at 170°C than at 150°C?
2.5
Calculate the silver ion concentration in a saturated solution of silver(I) carbonate (Ksp = 8.1 × 10⁻¹²).
2.5 × 10⁻⁴ M
Rubidium has a heat of vaporization of 69.0 kJ/mol at its boiling point (686°C).
Calculate ΔS for:
Rb(l) → Rb(g)
71.9 J/K·mol
Which species undergoes reduction?
Sn | Sn²⁺ || NO₃⁻ (acid soln), NO(g) | Pt
NO₃⁻
A 15.00% by mass solution of lactose (C₁₂H₂₂O₁₁, 342.30 g/mol) in water has a density of 1.0602 g/mL at 20°C. What is the molarity of this solution?
0.4646 M
1.25 moles of NOCl were placed in a 2.50 L reaction chamber at 427°C. After equilibrium was reached, 1.10 moles of NOCl remained.
Calculate the equilibrium constant, Kc, for the reaction:
2NOCl(g) ⇌ 2NO(g) + Cl₂(g)
5.6 × 10⁻⁴
Which of the following would decrease the Ksp for PbI₂?
A) Lowering the pH of the solution
B) Adding a solution of Pb(NO₃)₂
C) Adding a solution of KI
D) None of the above — the Ksp of a compound is constant at constant temperature
None of the above —the Ksp of a compound is constant at constant temperature
For the reaction:
H₂(g) + S(s) → H₂S(g)
ΔH° = −20.2 kJ/mol and ΔS° = +43.1 J/K·mol
Spontaneous at all temperatures
Calculate the standard cell emf:
Mg | Mg²⁺ || NO₃⁻ (acid soln) | NO(g) | Pt
3.33 V
The specific heat of liquid ethanol, C₂H₅OH(l), is 2.46 J/g·°C and the heat of vaporization is 39.3 kJ/mol.
The boiling point of ethanol is 78.3°C.
What amount of enthalpy is required to heat 50.0 g of liquid ethanol at 23.0°C to vapor at 78.3°C?
19.5 kJ
A 0.10 M HF solution is 8.4% ionized.
Calculate the H⁺ ion concentration.
8.4 × 10⁻³ M
Will a precipitate of magnesium fluoride form when 300. mL of 1.1 × 10⁻³ M MgCl₂ are added to 500. mL of 1.2 × 10⁻³ M NaF? (Ksp for MgF₂ = 6.9 × 10⁻⁹)
A) Yes, Q > Ksp
B) No, Q < Ksp
C) No, Q = Ksp
D) Yes, Q < Ksp
No, Q < Ksp
Which response includes all the following processes that are accompanied by an increase in entropy?
A) 1, 2, 3, 4
B) 1, 2
C) 2, 3, 4
D) 3, 4
E) 1, 4
3, 4
Calculate the cell emf at 25°C:
2Ag⁺ (0.010 M) + H₂(1 atm) → 2Ag(s) + 2H⁺ (pH = 10.0)
1.27 V
The vapor pressure of water at 20°C is 17.5 mmHg.
What is the vapor pressure of water over a solution prepared from 2.00 × 10¹ g of sucrose (C₁₂H₂₂O₁₁) and 3.50 × 10¹ g of water?
17.0 mmHg
You have 500.0 mL of a buffer solution containing 0.20 M acetic acid (CH₃COOH) and 0.30 M sodium acetate (CH₃COONa).
What will the pH of this solution be after addition of 20.0 mL of 1.00 M NaOH solution?
(Ka = 1.8 × 10⁻⁵)
5.07
Calculate the minimum concentration of Mg²⁺ that must be added to 0.10 M NaF in order to initiate a precipitate of magnesium fluoride. (Ksp for MgF₂ = 6.9 × 10⁻⁹)
6.9 × 10⁻⁷ M
Determine the equilibrium constant (Kp) at 25°C for:
CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g)
ΔG° = −28.5 kJ/mol
1.0 × 10⁵
Complete and balance the following redox equation. What is the coefficient of H₂O?
MnO₄⁻ + SO₃²⁻ → Mn²⁺ + SO₄²⁻ (acidic solution)
3
Which one of the following units would not be an acceptable way to express reaction rate?
A) M/s
B) M · min⁻¹
C) L · mol⁻¹ · s⁻¹
D) mol · L⁻¹ · s⁻¹
E) mmHg/min
mmHg/min
The pH at the equivalence point of a titration may differ from 7.0 due to:
A) the initial concentration of the standard solution
B) the indicator used
C) the self-ionization of H₂O
D) the initial pH of the unknown
E) hydrolysis of the salt formed
hydrolysis of the salt formed