Assignment:
Kinetics and equilibrium
1- An aqueous solution containing 18.9g of an unknown molecular (nonelectrolyte) compound in 103.0g of water was found to have a freezing point of -1.7 ° C.Calculate the molar mass of the unknown compound.Express your answer using two significant figures and g/mol
2- What is the osmotic pressure of a solution made by dissolving 25.0g of glucose, C6H12O6 , in enough water to form 325.0mL of solution at 34.0 ° C ?.
3- A solution of water (K f =1.86 ° C/m ) and glucose freezes at - 2.75 ° C . What is the molal concentration of glucose in this solution? Assume that the freezing point of pure water is 0.00 ° C Express your answer to three significant figures and include the appropriate units.
4- A solution of water (K b =0.512 ° C/m ) and glucose boils at 102.06 ° C . What is the molal concentration of glucose in this solution? Assume that the boiling point of pure water is 100.00 ° C .Express your answer to three significant figures and include the appropriate units.
5- At a certain temperature, the solubility of N 2 gas in water at 3.08atm is 72.5mg of N 2 gas/100 g water . Calculate the solubility of N 2 gas in water, at the same temperature, if the partial pressure of N 2 gas over the solution is increased from 3.08atm to 8.00atm .Express your answer numerically to three significant figures.
6- Consider the following reaction:
If the rate of change of [A] at a given point in time is -1.0 M/s, what is the rate of change of [C] at that same point in time? Choose from:
-1.0 M/s
+0.67 M/s
+1.0 M/s
+1.3 M/s
-1.3 M/s
7- Consider the rate law: rate = k [A]2 What will the units of k be for this rate law? Choose from: 1/s, M/s, 1/M2*s, 1/M*s, s/M
8- Identify the intermediate(s) in the following reaction mechanism:
9- Consider the following reaction:
If the reaction is at equilibrium, and then the I2(g) present at that point in time is removed, what will happen to the concentrations of H2(g) and HI(g)? Choose from:
H2(g) will increase; HI(g) will increase
H2(g) will decrease; HI(g) will decrease
H2(g) will decrease; HI(g) will increase
H2(g) will increase; HI(g) will decrease
The concentrations of H2(g) and HI(g) will remain unchanged
10- The rate law for the reaction:
A + 2 B → C
is:
rate = k[A][B]
If k = 0.318/M*s , and initial concentrations of reactants are: [A] = 0.50 M and [B] = 0.35 M, what will be the initial rate of this reaction?
11- Consider the following reaction:
Which of the species in the reaction are included in the equilibrium constant expression for the reaction? Choose from:
PbBr2(s) only
Pb2+(aq) only
Br-(aq) only
Pb2+(aq) and Br-(aq)
PbBr2(s), Pb2+(aq) and Br-(aq)
12- The following reaction:
CH3CHO → CH4 + CO
Is first order with k = 0.0693 / min
If the initial CH3CHO concentration is 0.435 M, what will be the CH3CHO concentration after 37.0 minutes?
13- Which of the following statements best describes chemical equilibrium? Choose from:
The forward and reverse reactions have stopped/
The concentration of products is greater than the concentration of reactants.
The rate of the forward reaction is equal to the rate of the reverse reaction.
The forward reaction has stopped, and the reverse reaction has commenced.
The concentrations of reactants and products are equal.
14- Consider the following equilibrium:
N2O4 (g) ? 2 NO2(g) Kc = 4.63 x 10-3 at 25 °C
A reaction vessel contains 0.2 M NO2 and 0.25 M N2O4. Which of the following statements is true?
Q = 0.16 and [NO2] increases
Q = 0.16 and [N2O4] increases
The reaction is at equilibrium
Q = 0.80 and [NO2] increases
Q = 6.25 and [N2O4] increases
15- The following reaction:
H2 (g) + I2 (g) ? 2 HI (g)
Has an equilibrium constant of 30.5 under certain conditions. If initial concentrations of reactants and product are: [H2] = 0.100 M; [I2] = 0.100 M; and [HI] = 0.250 M, what will be the equilibrium concentration of HI? Choose from:
0.100 M
0.040 M
0.330 M
0.450 M
0.244 M