chem 105 review
Which of the following radii comparisons is correct?
a. N³⁻ < N
b. Ti⁴⁺ > Ti³⁺
c. In³⁺ < In⁺
d. C⁴⁺ > C⁴⁻
e. As³⁻ < As³⁺
c. In³⁺ < In⁺
Which term is a measure of the energy required to increase the surface area of a liquid?
surface tension
For the reaction 2A + 3B → 4C + 5D, the rate of the reaction in terms of ΔA would be written as:
-½ ΔA/Δt
When a system is at dynamic equilibrium,
a. no reactions are occurring
b. a reaction is occurring in only one direction
c. the rates of the forward and reverse reactions are equal
d. all of the reactants have been converted to products
c. the rates of the forward and reverse reactions are equal
The pOH of a 0.0200M solution of HCl is
12.301
How many chlorine atoms are in 23 molecules of phosphorus pentachloride?
115
What amount of heat, in kJ, is required to vaporize 115.00 g of ethanol (C₂H₅OH)? (∆Hvap = 43.3 kJ/mol)
108kJ
The reaction X → products is second order in X and has a rate constant of 0.035M⁻¹s⁻¹. If a reaction mixture is initially 0.45M in X, what is the concentration of X after 155 seconds?
0.13M
Construct the expression for Kc for the following reaction.
CH₃COOH(aq) + H₂O(l) ⇌ CH₃COO⁻(aq) + H₃O⁺(aq)
Kc = [H₃O⁺] [CH₃COO⁻] / [CH₃COOH]
How many milliliters of 0.0200M Ca(OH)₂are required to neutralize 75.0 mL of 0.0300M HCl?
56.3mL
Metallic strontium crystallizes in a face-centered cubic lattice. The volume of the unit cell is 2.25 × 10⁸ pm³. What is the density of strontium metal in g/cm³?
2.59 g/cm³
FeCl₃ has a van't Hoff factor of 3.400. What is the freezing point (in °C) of an aqueous solution made with 0.8100m FeCl₃? (Kf for water is 1.860 °C/m)
-5.112°C
The radioisotope ¹⁴C (half-life = 5730 years) is used for carbon dating. What is the first order rate constant for ¹⁴C if the initial concentration is 1.5mmol?
1.21x10⁻⁴ years⁻¹
Consider the following reaction:
Mg(OH)₂(s) ⇌ Mg²⁺(aq) + 2OH⁻(aq)
At equilibrium, a 1.0L reaction vessel contains 5.3 moles of Mg(OH)₂ and concentrations of 0.0080M and 0.010M of Mg²⁺ and OH⁻ respectively. What is Kc for this equilibrium?
Kc = 8.0x10⁻⁷
What is [H⁺] in a 0.270 M solution of acrylic acid, CH₂CHCOOH (Ka = 3.16 × 10⁻⁵)?
2.92 × 10⁻³
Using the equations
SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol
2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol
CO₂ (g) → C(s) + O₂ (g) ∆H° = 394 kJ/mol
Determine the molar enthalpy (in kJ/mol) for the reaction
2 SrCO₃ (s) → 2 Sr (s) + 2 C(s) + 3 O₂ (g).
2440 kJ/mol
Write the balanced dissociation equation for solid lead(II) sulfate in aqueous solution. If it does not dissociate, simply write only NR.
A reaction has a rate law of Rate = (1.25M⁻¹s⁻¹)[A][B]. What concentration of [B] would give the reaction a rate of 0.158M/s if the concentration of [A] is 0.301M?
0.420M
Dinitrogen tetroxide partially decomposes according to the equilibrium:
N₂O₄(g) ⇌ 2NO₂(g)
A 1.000-L flask is charged with 3.00×10⁻² mol of N₂O₄. At equilibrium, 2.36×10⁻² mol of N₂O₄ remains. What is the Keq for this reaction?
Keq = 6.94x10⁻³
You have 0.600 L of an 0.300 M acetate buffer solution (i.e. [HC₂H₃O₂] + [C₂H₃O₂⁻] = 0.300 M) at pH 5.30. What will the new pH of the solution be if you add 85.0 mL of 1.000 M HCl to it. Acetic acid has a pKa of 4.74.
4.40
For a hydrogen atom, calculate the wavelength of light (in m) that would be emitted for the orbital transition of n(initial) = 5 to n(final) = 1. The Rydberg constant is 1.09678 x 10⁷ m⁻¹.
9.498 × 10⁻⁸ m
When 2.63 g of a polypeptide is dissolved in 101 mL of water, the resulting solution is found to have an osmotic pressure of 0.125 atm at 37.0 °C. What is the molar mass of the polypeptide? (Assume the volume doesn't change when the polypeptide is added.)
5.30 × 10³ g/mol
The rate constant for a reaction at 25℃ is 0.010 s⁻¹ and its activation energy is 35.8kJ/mol. What is the rate constant at 50.0℃?
0.031s⁻¹
Carbonyl bromide, COBr₂, can be formed by reacting CO with Br₂. A mixture of 0.400 mol CO, 0.300 mol Br₂, and 0.0200 mol COBr₂ is sealed in a 5.00L flask. Calculate equilibrium concentrations for all gasses. Kc = 0.680
CO(g) + Br₂(g) ⇌ COBr₂(g)
[CO] = 0.0807M
[Br2] = 0.0607M
[COBr2] = 0.0033M
Calculate the [NH₃] in a solution of 0.350 M ammonium cyanide (NH₄CN). Hint: Use the Ka of HCN (4.9 × 10⁻¹⁰) and the Kb of NH₃ (1.8 × 10⁻⁵) to calculate Kc for the reaction
NH₄⁺(aq) + CN⁻(aq) ⇌ NH₃(aq) + HCN(aq)
0.180 M