Solutions
If the solute of the solution has a mole fraction of 0.372, what is the mole fraction of the solvent?
0.628
What is a colligative property?
a. a property that depends on kinetics
b. a property that depends on the number of solute particles
c. a property that depends on molecular shape
b. a property that depends on the number of solute particles
The half-life of a reaction is
a. the time it takes for the amount of product formed to equal half the initial amount of reactant
b. one-half of the time the reaction will take to go to completion
c. the time it takes for the amount of reactant to decrease to one-half of its initial value
c. the time it takes for the amount of reactant to decrease to one-half of its initial value
If the following reaction was a second order in A and first order in B, what are the units of the rate constant?
A + B --> C
M-2 s-1
What is the molecularity of the elementary reaction below and what is the corresponding rate law?
N2 (g) + H2 (g) --> N2H2 (g)
e.
The Henry’s Law constant for the dissolution of CO2 in water is 3.40×10-2 M/atm. What is the concentration of CO2 in water if the partial pressure of CO2 over the water is 0.233 atm?
7.92 x 103- M
What is the osmotic pressure of a NaCl solution which consists of 17.6 g NaCl per liter of solution at 25 C?
14.7 atm
If a reaction is zero order in a reactant, when the concentration of the reactant is decreased by a factor of 2, the reaction rate will...
Stay the same
If the following reaction is second order in [N2O2], what is the concentration of N2O2 after 248 seconds if the initial concentrations is 1.21 M and k = 7.35 x 10^-3 M^-1 s^-1
0.377 M
The elementary steps for a catalyzed reaction are shown below. Identify the catalyst. Identify the reactive intermediate.
Step 1: H2O2 + Br --> BrO + H2O
Step 2: H2O2 + BrO --> Br + H2O + O2
Intermediate: BrO
Catalyst: Br
18.0g of NH4Cl is dissolved in 400 mL of solution. What is the molarity of this solution?
0.841 M
What is the vapor pressure of ethanol over a solution that is 49.8 g ethylene glycol (62.0682 g/mol, non- volatile, non-electrolyte) and 179 g ethanol (46.0688 g/mol) at 25 C?
P ethanol = 58.8 mmHg at 25 C
48.7 mmHg
Which of the following plots is NOT a straight line?
a. r vs. [A] for a zero order reaction in [A]
b. r vs [A] for a second order reaction in [A]
c. 1/[A] vs t for a second order reaction in [A]
d. [A] vs t for a zero order reaction in [A]
b. r vs [A] for a second order reaction in [A]
What is the half-life of a first-order reaction if the rate constant is 6.2 x 10-3 s-1
1.1 x 102 s
Slow
Fast
c.
An aqueous solution is 0.386 M CH3OH with a density of 0.987 g/mL. What is the molality of CH3OH in this solution?
0.396 molal CH3OH
Fill in the blanks: Raoult's law predicts that adding a solute to a solvent ______ the vapor pressure of the solvent. If the solute-solvent interactions are stronger than the solvent-solvent interactions, the actual vapor pressure will be _______ than that predicted by Raoult's law.
Word bank for first blank: reduces or raises
Word bank for second blank: lowers or higher
Reduces; lower
N2O5 (g) --> 2NO2 (g) + 1/2 O2 (g)
Given the data in the table above, what is the average rate of formation of NO2?
1.11 x 103- M/s
O2 (g) + 2NO (g) --> 2NO2 (g)
Based on the method of initial rates, what is the observed rate law for this reaction?
a.
What is the date and time for CHEM 1308 EXAM 1?
Feb 12th (Thursday) at 7:00 pm.
An aqueous solution is 12.8% by mass CH2O. What is the mole fraction of CH2O in this solution?
0.0809 CH2O
If an aqueous solution has a freezing point of -0.591 C, what is the boiling point of this solution?
Kf(water) = 1.86 C/m Kb(water) = 0.512 C/m
100.163 C
Which of the following does NOT represent a proper expression for the rate of this reaction?
S2O8-2 (aq) + 3I- (aq) --> 2SO42- (aq) +I3- (aq)
d.
At a particular temperature, N2O5 decomposes according to a first-order rate law with a half-life of 3.0s. If the initial concentration of N2O5 is 1.0 x 1016 molecules/cm3 , what will be the concentration in molecules/cm3 after 15.5 s?
2.8 x 1014
Fast
Slow
b.