Which of the following compounds should be soluble in CCl4 and why?
a. NaCl
b. H20
c. NaOH
d. C818
d. C8H18 because like dissolves like.
100
Does the solubility of a gas in liquid solvent increase or decrease with increasing temperature? What about the solubility of a solid or liquid in a liquid solvent?
decrease for gas, increase for solid/liquid
100
What are the four colligative properties?
Vapor Pressure Lowering, BP Elevation, FP Depression, Osmosis
100
How do we measure reaction rate?
how much the [reactant] decreases or how much [product] increases over time
100
What is the difference between average and instantaneous rate?
avg- change in concentrations in any particular time period (interval) inst - change in concentration at one particular time
200
Which of the following aqueous solutions has the highest boiling point?
a. 0.2 m KCl b. 0.2 m Na2SO4 c. 0.2 m Ca(NO3)2 d. 0.2 m KCl and 0.2 m Na2SO4
e. 0.2 m Na2SO4 and 0.2 m Ca(NO3)2
e.
200
Explain the terms saturated, unsaturated, and super saturated.
solute and solvent in dynamic equilibrium, less solute than saturation (more solute will dissolve), more solute than saturation (unstable)
200
Explain what the van't Hoff factor is and give an example.
i = the number of particles in solution i.e. NaCl i=2
200
For the reaction BrO3- + 5 Br- + 6 H+ 3 Br2 + 3 H2O at a particular time, the rate of disappearance of BrO3- = 1.5 x 10-2 M/s. What is the corresponding rate for Br- at the same instant?
7.5 x 10-2 M/s
200
What are the three most common reaction orders and what do they tell us?
0,1,2 - relationship between rate and concentration of reactants
300
What is the molarity of a solution of 10.0% by mass CaSO4 (MM = 208.5 g/mol)? The density of the solution is 1.10 g/mL.
0.528
300
Calculate the % mass of KNO3 in a solution made from 45.0 g KNO3 and 295 mL of water @ 250C. The density of water is 0.997 g/ml at this temperature.
13.3%
300
Calculate the molality of a solution containing 14.3 g of NaCl in 42.2 g of water.
5.81
300
Use the following data to determine the rate law and for the reaction
2 NO + H2 --> N2O + H2O.
Expt. # [NO]0 [H2]0 Initial Rate
1 0.021 0.065 1.46 M/min
2 0.021 0.260 1.46 M/min
3 0.042 0.065 5.84 M/min
k[NO]m[H2]n = k[NO]2
300
At 25 C the rate constant for the first-order decomposition of a pesticide solution is 6.40 x 10-3 min-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25 C?
2.11 x 10-2 M
400
How many grams of NH3 will dissolve in 0.10 L of solution when its partial pressure is 7.6 torr?
0.99 g
400
What is the osmotic pressure of a solution that contains 13.7 g of propanol (C3H8O) dissolved in enough water to make 500. mL of solution at 270C.
11.2 atm
400
Benzaldehyde (MM = 106.1 g/mol) is used in the manufacture of dyes, perfumes, and flavorings. What would be the freezing point of a solution prepared by dissolving 75.00 g of benzaldehyde in 850.0 g of ethanol? Kf = 1.99)C/m; freezing point of pure ethanol = -117.3 0C.
-119.0 degrees C
400
The activation energy for the following first-order reaction is 102 kJ/mol:
N2O5 --> 2 NO2 + ½ O2 . The value of the rate constant (k) is 1.35 x 10-4s-1 at 35 C. What is the value of k at 0 C?
8.18 x 10-7 s-1
400
The thermal decomposition of acetaldehyde, CH3CHO -> CH4 + CO, is a second-order reaction. The following data were obtained at 518 C:
time,s pressure CH3CHO, mmHg
0 364
42 330
105 290
720 132
Calculate the half-life for this reaction.