Exam 1
Which substance has the highest boiling point? CF4, CH4, CBr4, CCl4?
CBr4
For a certain unimolecular, 2nd order reaction:
A → Products
[A]0 = 0.406 M and k = 0.00391 M-1·s-1
What will [A] be after 284 seconds?
0.280
The pKa for a weak acid is 11.40, what is Kb for its conjugate base?
2.51x10^-3
What type of rxn forms a peptide bond? Addition or Condensation?
Condensation
Consider the mechanism.
Step 1: 2A <> B+C (eq)
Step 2: B+D > E (slow)
Determine the rate law for the overall reaction, where the overall rate constant is represented as 𝑘.
R= k([D][A]^2)/([C])
Which has the stronger intermolecular forces? Butane or 2-methylpropane? Why?
Butane :: linear molecules have higher LDF forces than their nonlinear counterparts of the same mass
Given the following data for the reaction A → B, determine the activation energy, Ea, of the reaction (in kJ/mol).
k (s-1) T (℃)
3.10 x 10−4 9.059.059.05
6.43 x 10−2 105.0105.0105.0
49.3 kj/mol
What is the pH of 2.4024 M pyridine (Kb = 1.7 x 10-9)?
9.81
Identify the daughter element:
Th-230 > He-4 + ??
Ra-226
An aqueous solution consists of 0.10 M Ca2+ and 0.30 M Ba2+.
Given that Ksp for BaF2 is 1.5 x 10-6 and Ksp for CaF2 is 3.2 x 10-11, calculate the [F−] needed to separate the ions.
2.24x10^-3
What is the molality of a solution consisting 13.33 grams of glucose (C6H12O6) dissolved in 700 mL of water? (Assume the density of water is 1.0 g/mL.)
0.106
In the atmosphere nitric oxide can react with oxygen to produce nitrogen dioxide.
2NO (g) + O2 (g) ⇌ 2NO2 (g)
If Kp for this reaction at 184°C is 3.22 times 10 to the 4 power;3.22×1043.22\times 10^{4}, find Kc.
1.21x10^6
A certain reaction has ΔH = -294 kJ and ΔS = -112.1 J/K. At what temperature does this reaction become spontaneous?
2623 K
What is the name of this molecule? CH3CCCH2COH
3-pentynal
Calculate the equilibrium pH of the titration of 70ml 0.23M HNO2 with 0.23M NaOH
Ka = 4.5x10^-2
Kb = 2.2x10^-13
7.2
Henry's law constant, kh for nitrogen gas is about double that of kh for oxygen gas. The partial pressures of O2 and N2 in air are approximately 0.2 atm and 0.8 atm, respectively. According to Henry's law, the solubility of N2 in water will be about how many times greater than that of O2 in water?
8 times
For the reaction:
CO2 ⇋ . CO (g) + O (g)
Kp = 2.5 x 10−8
If a reaction starts with P(CO2) = 2.022.022.02 atm, what is the pressure of the CO at equilibrium?
2.25x10^-4
Calculate the value of ΔG (in kJ/mol) for an equilibrium reaction at 303030 °C with K = 2.13×10−2
9.7 kJ/mol
Balance this rxn in a basic solution:
Al(s)+NO3^- > NO2 + Al^3+
3H2O + Al + 3NO3^- > Al^3+ + 3NO2 + 6OH-
The nuclear mass of Ti-48 is 47.9359amu. Calculate the binding energy per nucleon for Ti-48.
p+ = 1.00728
nº = 1.00866
1.39744x10^-12 J/nucleon
A solution of methanol in water at 25 ℃ lowers the vapor pressure of the water by 0.250.250.25 torr.
The vapor pressure of pure water at 25 ℃ is 23.76 torr.
What is the vapor pressure (in torr) of water over an aqueous solution of CaCl2, made to the same concentration as the methanol solution and also at 25 ℃?
23.01
The reaction of bromine gas with chlorine gas, shown below, has a Kc value of 8.208.208.20 at 200ºC. Suppose you load a closed vessel at 200ºC with 0.1000.1000.100 M bromine gas and 0.1500.1500.150 M of chlorine gas. What will the concentration of BrCl (g) be at equilibrium if initially there was no BrCl (g)?
Br2 (g) + Cl2 (g) ⇌ 2BrCl (g)
0.14
What is the solubility (M) of CaF2 (Ksp = 3.9 x 10-11) in a solution with 0.0600.0600.060 M NaF (aq)?
1.08x10^-8
Calculate the cell potential under the given conditions:
Cu(s)+Fe^2+ (.2M) > Cu^2+ (0.01M) + Fe
Ecu = 0.34
Efe = -0.44
-0.74 Volts
At 30.0°C, milk sours in 24 hours. If kept refrigerated, at 5.0°C, the same milk takes 6 days to sour. Estimate the activation energy in kJ/mol for the reaction that leads to the souring of the milk.
50.95 kJ/mol