Chem II Jeopardy Review

Exam 1

100

The point on the phase diagram graph where all lines intersect is called the?

Triple Point

200

The solubility of CO₂ gas is 0.15 M and it has a Henry's gas law constant of 0.034 M/atm. Find the partial pressure of CO₂ gas in torr.

3353 torr

300

A system has an initial temperature of 69.4 C and an initial pressure of 1 atm. Find the temperature of the system in Celsius given that the change in enthalpy is 17.2 kJ and the final pressure is 514 torr.

48.6 C

400

0.145 g of an unknown molecule is added to a 255 mL solution at 25C. Given the osmotic pressure is 24.6 torr find the molar mass of the unknown molecule.

487 g/mol

500

Convert 4 m NaOH to molarity (solution has a density of 1.48 g/mL).

5.1 M

Exam 2

100

Which of the following shows the correct equilibrium expression for each equilibrium process? 

a) CaCO3(s) ↔ CaO(s) + CO2(g) 𝐾 = [𝐶𝑂2] 

b) 2H2(g) + O2(g) ↔ 2H2O(l) 𝐾 = [𝐻2𝑂]²/ [𝐻2 ]²[𝑂2] 

c) N2(g) +3H2(g) ↔ 2NH3(g) 𝐾 = [𝑁2 ][𝐻2 ]³/[𝑁𝐻3 ]²

d) N2O4(g) ↔ 2NO2(g) 𝐾 = [𝑁2𝑂4]

a) K = [CO₂]

200

Which is named incorrectly?

H₂CO₃ = carbonic acid

H₂Se = hydroselenic acid

IO₄ = iodic acid

HBrO = hypobromous acid

IO₄ = iodic acid

300

Calculate the value of Kp for the following reaction:

N₂(g) + H₂(g) <-> NH₃(g) 

Kc = 3.7x10⁸ at 298K

Hint: Kp = Kc(RT)^{Delta n}

6.2x10⁵

400

Decomposition of SO₂Cl₂ is first order in SO₂Cl₂ and has a rate constant of 1.42x10^-4 s^-1. How long does it take to reach 35.0% of the initial concentration of SO₂Cl₂?

2.05 hours

500

Calculate the concentration of H₂S gas at equilibrium if a 1.50-L reaction vessel initially contains 3.0 M in NH₃, 5.0 M in H₂S, and 20. M in NH₄HS. At the temperature of the reaction, K = 5.5.

NH3(g) + H2S(g) <-> NH4HS(s)

Hint: You have to use the quadratic equation :(

2.1 M

Exam 3

100

Which of the following is TRUE? 

a) The values of Ka1 and Ka2 in a polyprotic acid change depending on acid concentrations. 

b) Nitric acid is a polyprotic acid. 

c) Ka2 is usually larger than Ka1 for polyprotic acids. 

d) HPO4 2−+H2O H3O + +PO4 3− is the expression for the second ionization step of phosphoric acid. 

e) None of the above are true.

e) None of the above are true.

200

Rank the compounds below in order of increasing pH:

 1.NaI  2.NH4Cl  3.K3PO4  4.HBr  5.CH3NH3NO2 

HINTS: Kb of CH3NH2 is 4.38x10−4 Ka of HNO2 is 4.0x10−4     Ka3 for H3PO4 = 4.2x10−13

4<2<1<5<3

300

Balance this redox reaction in acidic solution.

BrO₃^-+N₂H_4-> Br^-+N₂

3N₂H₂+2BrO₃^-->3N₂+2Br^-+6H₂O

400

Calculate the pH of 0.38 M benzoic acid in 0.24 M sodium benzoate solution. HINT: Ka of benzoic acid is 6.5x10^-5.

3.99

500

You titrate 100 ml of 0.250 M benzoic acid solution with a 0.450 M NaOH solution. HINT: Ka of benzoic acid is 6.5x10^-5. Calculate the pH at the equivalence point.

8.7 

New Stuff

100

This is the opposite of a Voltaic/Galvanic Cell

Electrolytic Cell

200

Calculate the potential of the concentration cell at 25C:

 Al(s) + Al^3+(aq, 1.15 M) → Al^3+(aq, 0.015 M) + Al(s)

Hint: Use Nernst Equation 

0.037

300

Calculate the maximum amount of work that can be obtained at 25C from an electrochemical cell using Na and MnO2 electrodes. HINT: Write a balanced chemical reaction first.

756 kJ

400

How long will it take (in hours) to electroplate 11.1 g of copper from a Cu2+ solution using a current of 3.8 A?

2.5 hrs

500

You want to produce Na metal by the electrolysis of molten NaCl. You want to produce 1.5 kg of Na in an hour. How many amps of current must be applied?

1749 A