38) The equation of state of an ideal gas is PV = nRT. The constant “n” refers to the number of
a) atoms in the gas b) molecules in the gas
c) particles in the gas
d) moles of the gas
39) The specific latent heat of vaporization of a substance is the quantity of energy required to
a) raise the temperature of a unit mass of a substance by one degree
b) convert a unit mass of liquid to vapour at constant temperature and pressure
c) convert a unit mass of solid to vapour at constant temperature and pressure
d) convert a unit mass of liquid to vapour at a temperature of 100 oC and a pressure of one atmosphere
40) When a gas in a cylinder is compressed at constant temperature by a piston, the pressure of the gas increases.
Consider the following three statements:
I.
The rate at which the molecules collide with the piston increases
II.
The average speed of the molecules increases
III.
The molecules with each other more often
Which statement(s) correctly explain the increase of pressure? a) I only b) II only c) I and II d) I and III
41) The temperature of an ideal gas is a measure of the gas molecule’s
a) average velocity b) maximum velocity c) average kinetic energy d) total kinetic energy
42) The pressure of a gas exerts on a container wall is due to the
a) change in KE of the gas molecules as they strike the wall
b) change in momentum of the gas molecules as they strike the wall
c) average PE of the gas molecules
d) force of repulsion between the gas molecules
43) Jillian heats up her bath water by adding hot water at 80 oC to 9 times that amount of water already in the
bath at 30 oC. The best estimate for the final temperature of the water (in degrees C) is
a) 35
b) 40
c) 45
d) 50
44) When two bodies are in contact, the direction of thermal energy transfer depends on their
a) surface area
b) masses c) specific heat capacities d) temperatures
45) The specific latent heat of fusion of a substance is defined as the amount of thermal energy required to change
the phase of
a) the substance at constant temperature
b) unit mass of the substance to liquid at constant temperature
c) unit mass of the substance at constant temperature
d) the substance to gas at constant temperature
46) A solid is at an initial temperature of 500 K. The solid is heated so that its temperature rises by 50 K.
What are the initial temperature and temperature rise of the solid, as measured on the Celsius scale?
a)
b)
c)
d)
Initial Temp.
227 oC
227 oC
773 oC
773 oC
Temperature Rise
50 oC
323 oC
50 oC
323 oC
47) A copper block and a steel block each have the same mass. The copper block is at a higher temperature than the
steel block.
The blocks are placed in thermal contact and they then reach thermal equilibrium. There is no energy exchange
with the surroundings.
How do the magnitude of the change in Temperature (T) and the magnitude of the change in internal energy
(U) of the two blocks compare?
a)
b)
c)
d)
T
same
same
different
different
U
same
different
same
different
48) Which of the following correctly describes the changes in the kinetic energy of the molecules and the potential
energy of the molecules as a liquid changes phase to a gas?
a)
b)
c)
d)
Kinetic Energy of the molecules
no change
no change
increases
increases
Potential Energy of the molecules
increases
no change
increases
no change
49) The specific heat capacity of an object is defined as the thermal energy required to raise the temperature of
a)
b)
c)
d)
the volume of the object by 1K
unit volume of the object by 1K
the mass of the object by 1K
unit mass of the object by 1K
50) A small copper sphere at 90 oC is place in a beaker of water which has an initial temperature of 20 oC. The
maximum temperature of the water afterwards is measure to be 31 oC.
Which of the following is the most correct statement?
a) Some of the vibrational kinetic energy of the copper atoms has been transferred to the water molecules
b) The energy of the copper atoms has been partially destroyed
c) Thermal energy from the copper atoms has been used mainly to break bonds between water molecules
d) The results of this experiment can be used to find the specific latent heat of vaporization for water.