chem 105
Which of the following sets of quantum numbers is not allowed?
a. n = 2 , ℓ = 0 , mℓ = 0
b. n = 3 , ℓ = 2 , mℓ = 0
c. n = 2 , ℓ = 2 , mℓ = 2
d. n = 3 , ℓ = 1 , mℓ = -1
c. n = 2 , ℓ = 2 , mℓ = 2
What amount of heat, in kJ, is required to vaporize 115.00 g of ethanol (C₂H₅OH)? (∆Hvap = 43.3 kJ/mol)
108kJ
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
What is the hybridization of all carbons present in nicotine?
sp2 / sp3
FeCl₃ has a van't Hoff factor of 3.400. What is the freezing point (in °C) of an aqueous solution made with 0.8100 m FeCl₃? (Kf for water is 1.860 °C/m)
-5.112°C
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]
What is the bond order of O2+?
2.5
Lead has a face-centered cubic lattice with all atoms at lattice points and a unit-cell edge length of 4.950 Å. What is the density, in g/cm³, of lead? (1.0 x 10⁻¹⁰ m = 1 Å)
11.35g/cm3
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
An old 0.500 L lecture bottle of hydrogen chloride (HCl) was found in a lab and needed for a reaction. A pressure regulator indicated a pressure of 70.0 psi, and the lab was at room temperature (25 °C). What mass of gaseous hydrogen chloride was left in the lecture bottle?
3.55g
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
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
5C₂O₄²⁻(aq) + 2MnO₄⁻(aq) + 16 H⁺(aq) → 2Mn²⁺(aq) + 8H₂O(l) + 10CO₂(g)
A 0.3754 g sample of sodium oxalate is dissolved in 100 mL of acid solution, and the permanganate solution is added slowly from a buret. The endpoint is reached when 33.25 mL of the permanganate solution has been added. What is [MnO₄⁻], the molar concentration of the permanganate solution?
0.03370M
You dissolve a 30.0 g mixture of glucose (C₆H₁₂O₆) and NaCl in 1.00 kg water. The freezing point of this solution is found to be -0.851°C. Assuming ideal behavior, what is the mass (in grams) of glucose in the mixture? (Kf for water is 1.86°C･kg/mol).
19.9g
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