gases (ch. 10)
What is NOT an assumption made in kinetic-molecular theory
a) attractive forces between gas molecules are negligible
b) gas particles are in continuous motion except at low temperatures
c) Collisions between gas molecules do not result in a loss of energy
d) Repulsive forces between gas molecules are negligible
e) temperature is proportional to average kinetic energy
B
in which of the following molecules is hydrogen bonding likely to be the most significant component of the total intermolecular forces?
a) CH4 b) C6H13NH2 c) C5H11OH d) CH3OH e) CO2
D
calculate the molarity (in mM) of a solution of Mg2SO4 if at 57 oC, the osmotic pressure is 437 mmHg.
7.1 mM
calculate the half-life of a substance that decomposes at a first-order reaction rate if the rate constant of its decomposition is 0.345 s-1
2.01 sec
the following reaction has a Kp value of 1.23 at 25 ºC. find the Kc value of the reaction
4NH3(g) + 3O2(g)→2N2(g) + 6H2O(l)
1.08 x 107
a 2.2 mol sample of ammonia gas at a pressure of 1840 mmHg is compressed from a volume of 3.4 L to 2.0 L at a constant temp. What is the pressure (in torr) after compression?
3128 torr
what intermolecular forces are present in each of these molecules?
a) H2O b) SF6 c) CO2 d) CH3COOH e) H2S
a) h-bonding, dipole-dipole, LDF
b) LDF
c) LDF
d) h-bonding, dipole-dipole, LDF
e) dipole-dipole, LDF
at 25.0°C the Henry's Law constant for argon (Ar) gas in water is 1.4 × 10-3 M/atm. Calculate the mass in grams of Ar gas that can be dissolved in 900 mL of water at 25.0°C and a Ar partial pressure of 2.23 atm
0.11 g
using the following data, determine a) the overall order of the reaction, and b) the rate law of the reaction
rxn | [ClO2] | [OH–] | Initial rate (M/s)
1 | 0.060 | 0.030 | 0.0248
2 | 0.020 | 0.030 | 0.00276
3 | 0.020 | 0.090 | 0.00828
a) 4
b) rate = k[ClO3]3[OH–]
consider the following reaction
2 A ⇌ B + C Kc = 0.33
determine the equilibrium constant for this reaction
4C + 4B ⇌ 8A
84
If the pressure of 12.5 g of hydrogen gas at 28 oC is 1.5 atm in a 2.8 L balloon, then calculate the temperature (in Celsius) at which the pressure is 860 torr when the volume is 2.4 L
-78 oC
which of the following compounds has the highest boiling point? which would most likely have the lowest?
A) HOCH2CH2OH B) H3COCH3
C) CH3CH2CH2CH3 D) CH3CH2OH
the vapor pressure of pure acetyl bromide (CH3COBr) is measured to be 0.49 atm. Suppose a solution is prepared by mixing 86.0g of acetyl bromide and 58.2g of chloroform (CHCl3). Calculate the partial pressure of acetyl bromide vapor above this solution in torr
219. torr
a reaction has the following rate law
rate = k[NO2]
find the rate constant (w/ proper units) of the reaction at 35 ºC if the concentration of NO2 goes from 0.82 M to 0.35 M in 5.8 sec
0.15 s-1
the following reaction has a Kc value of 2.3 x 10-4.
K2CO3(aq) + H2O(l) + CO2(g) → 2KHCO3(aq)
if at a certain time [K2CO3] = 0.55 M, [CO2] = 0.32 M, and [KHCO3] = 0.24 M, determine which direction the reaction will proceed
to the left
what is the temperature (in Celsius) of carbon tetrafluoride gas in a container of 21.3 L if it has a density of 3.72 g/L and is at a pressure of 855 torr?
51.2 oC
How much heat is released when 95.0 g of steam at 100.0°C is cooled to ice at -15.0°C? 𝚫Hvap of water is 40.67 kJ/mol, 𝚫Hfus for water is 6.01 kJ/mol, the molar heat capacity of liquid water is 75.4 J/(mol · °C), and the molar heat capacity of ice is 36.4 J/(mol · °C)
289. kJ
a certain liquid X has a normal freezing point of −2.30°C and a freezing point depression constant Kf = 3.70 °C·kg·mol-1. Calculate the freezing point of a solution made of 47 g of potassium bromide dissolved in 500 g of X.
–8.15 ºC
a reaction has the following rate law
rate = k[A]2, k = 0.81 M-1·s-1
find the initial concentration of A if after 2.2 sec, its concentration drops down to 0.22 M
0.36 M
A mixture of 5.0 x 10-3 M H2 and 1.0 x 10-2 M of I2 is placed in a container at 448 ºC and allowed to come to equilibrium
At equilibrium, the concentration of HI is 1.87 x 10-3M; calculate Kc
0.095
Use the van der Waals equation to calculate the pressure of 55. g Cl2 gas in a 12.2 L container at a temperature of 338 oC. Then calculate the pressure using the ideal gas laq
a = 4.567 b = 0.0324 L/mol
a) 2.92 atm b) 2.93 atm
The enthalpy of vaporization of Substance X is 25.0 kJ/mol and its normal boiling point is 36.°C. Calculate the vapor pressure (in torr) of X at 5.°C. (hint: at normal boiling point, vapor pressure = 1 atm
257 torr
an unknown liquid has a boiling point of 85.2 ºC. calculate the molarity of calcium fluoride in 500g of a solution w/ a boiling point of 89.6 ºC if the liquid has a density of 1.2 g/mL. the Kb value is 2.20 °C·kg·mol-1
0.8 M
the rate constant of a certain reaction is 0.089 M-1·s-1 at 22 ºC, and at 39 ºC is 0.142 M-1·s-1. calculate the activation energy (in kJ/mol) of this reaction
7.17 x 10-7 kJ/mol
predict the change in direction for the following changes for this reaction at equilibrium
O3(g) + H2O(l) ⟶ H2(g) + 2O2(g) 𝚫H = –24.4 kJ/mol
a) partial pressure of O3 increases
b) amount of H2O decreases
c) partial pressure of oxygen decreases
d) volume of container decreases
e) temperature increases
f) a catalyst is added
a) to the right
b) no shift
c) to the right
d) to the left
e) to the left
f) no shift