Module 4
Which one of the following substances is expected to have the lowest melting point?
a)BrI
b)CsI
C) LiI
d)NaI
e)RbI
BrI
The solubility of CO2 gas in water...
a) increases with increasing gas pressure
b) increases with decreasing gas pressure
c) decreases with increasing gas pressure
d) is not dependent on pressure
a)increases with increasing gas pressure
Which one of the following units would not be an acceptable way to express reaction rate?
a) M/s
b) M x min^-1
c) L x mol^-1 x s^-1
d) mol x L^-1 x s^-1
e) mmHg/min
c) L x mol^-1 x s^-1
At 25 degree Celcius the rate constant for the first order decomposition of a pesticide solution is 4.8×10^−3 min^−1. If the starting concentration of pesticide is 0.0420M, What concentration will remain after 75 min at 25 degree celcius?
0.0293M
A farmer has 17 sheep. All but 9 run away. How many sheep does he have left?
9
Which two properties are more typical of molecular compounds than of ionic compounds?
1. They are gases or liquids at room temperature
2.They have high melting points
3. Solids do not conduct electricity, but liquids do
4. Atoms share electrons
a) 1 and 4
b) 1 and 3
c) 2 and 3
d) 2 and 4
e) 3 and 4
a) 1 and 4
Dissolving a solute such as KOH in a solvent such as water results in...
a) an increase in the melting point of the liquid
b) a decrease in the boiling point of the liquid
c) a decrease in the vapor pressure of the liquid
d) no change in the boiling point of the liquid
c) a decrease in hte vapor pressure of the liquid
A rate costant with the units of L^2 mol^-2 s^-1 is consistent with...
a) Zeroth order reaction
b) First order reaction
c) Second order reaction
d) third order reaction
e) fourth order reaction
d) third order reaction
At 760K, 20% of a sample of cyclopropene changes to propene in 6.8min. What is the half-life of cyclopropane at 760K?
24.8 min
A pizza is cut into 8 slices. If you take 3 slices, how many slices do you have?
3 slices
Which one of the following substances will have both dispersion forces and dipole- dipole forces?
a) HCl
b) BCl3
c) Br2
d) H2
e) CO2
a)HCl
A 30% by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20 degree Celcius. what is the molarity of this solution?
3.41M
For the reaction:
BrO3^- + 5 Br^- + 6H^+ --> 3Br2 + 3H2O
at a particular time, -Δ[BrO3^-]/ Δt = 1.5 x 10^-2 M/s. What is -Δ[Br^-]/Δt at the same time?
7.5 x 10^-2 M/S
At 25 degree celcius, the second order reaction NOCl(g) --> NO(g) + 1/2 Cl2(g) is 50% complete after 4.5 hours when the initial concentration of NOCl is 3.20 mol/L. How long will take for the reaction to be 75% complete?
13.5 hours
Which weighs more:
1 kg of feathers or 1 kg of steel?
Same
Which of the following properties indicate the presence of weak intermolecular forces in a liquid?
a) High heat of vaporization
b) High critical temperature
c) high vapor pressure
d) High BOILING POINT
e) None of the above
c) High vapor pressure
The density of a 10M CH3OH(methanol) solution is 0.93 g/mL. What is the molality of this solution? H2O is the solvent
16.4
The reaction A + 2B --> products has the rate law , rate= k[A][B]^3. If the concentration of B is doubled while that of A is unchanged, by what factor will the rate of reaction increase?
a) 2
b) 4
c) 6
d) 8
e) 9
d)8
The activation energy for the following reaction is 55 kJ/mol
Sn^2+ + 2Co^3+ --> Sn^4+ + 2Co^2+
By what factor (how many times) will the rate constant increase when the temperature is raised from 15 degree celcius to 35 degree celcius?
4.4 times
Why did the math book look sad?
Because it had too many problems
Which of the following liquids would have the lowest viscosity at 25 degree Celcius?
Draw answers on the board
a)
During osmosis…
a) pure solvent diffuses through a membrane but solutes do not
b)pure solutes diffuse through a membrane but solvent does not
c) pure solvent and a solution both diffuse at the same time through a membrane
D) gases diffuse through a membrane into a solution and build up pressure.
a)pure solvent diffuses through a membrane but solutes do not
A kinetic study of this reaction under a certain set of conditions yielded the data below
Exp. [ClO2] (M). [OH^-](M) -Δ[ClO2]/Δt(M/s)
1. 0.050 0.100 5.75 x10^ -2
2. 0.100 0.100 2.30 x 10^-1
3. 0.100 0.050 1.15 x 10^-1
Which one of the following is the rate law for this reaction?
a) rate= k[ClO2][OH^-]
b) rate= k[ClO2]^2 [OH^-]
c) rate= k[ClO2][OH^-]^2
d) rate= k[ClO2]^2 [OH^-]^2
e) rate= k[ClO2]4 [OH^-]
b) rate= k[ClO2]^2 [OH^-]
The rate law for the reaction
2NO2 + O3 --> N2O5 + O2
is rate=k[NO2][O3]. Which of the following mechanisms is consistent with this rate law?
a) NO2 + NO2 --> N2O4 (fast)
N2O4 + O3 --> N2O5 + O2 (slow)
b) NO2 + O3 --> NO5 (fast)
NO5 + NO5 --> N2O5 + 5/2 O2 (slow)
c) NO2 + O3 --> NO3 + O2 (slow)
NO3 + NO2 --> N2O5 (fast)
d) NO2 + NO2 --> N2O2 + O2 (slow)
N2O2 + O3 --> N2O5 (fast)
c) NO2 + O3 --> NO3 + O2 (slow)
NO3 + NO2 --> N2O5 (fast)
Why can’t a nose be 12 inches long?
Because it would be a foot