When the gas in a cylinder is compressed at constant temperature
by a piston, the pressure of the gas increases.When the 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 walls increases.
II The average speed of the molecules increases.
III The molecules collide with each other more often.
Which statement(s) correctly explain(s) the increase in pressure.
a I only.
b II only.
c I and II only.
d I and III only.
A gas is enclosed in a vertical cylinder fitted with a piston.
Weights are placed on the piston. When the gas is at 27 °C the piston is in equilibrium at a height h above the base of the cylinder as shown above.
To what value should the gas temperature be increased for the piston to be in equilibrium at a height of 2h above the base?
a 54°C
b 150°C
c 327°C
d 600°C
Let the average translational kinetic energy, at a temperature
T, of helium (molecular mass 4 g/mole) be K. The average translational
kinetic energy, at the same temperature, of neon (molecular mass
20 g/mole) would be....
a ... 5K.
b ... 2.25K.
c ... K.
d ... 0.2K.
An enclosed gas is originally at 27 °C at a certain pressure. The gas volume is then doubled as shown.
In order to restore the pressure to its original value, to what value must the temperature now be adjusted, at this new volume?
a -123 °C
b 13.5 °C
c 54 °C
d 327 °C
When the volume of an enclosed gas is increased at a constant
temperature, the pressure exerted by the gas on the container
wall decreases. Consider the following statements as possible
explanations for this:
I the average speed at which the gas molecules strike the walls decreases.
II the rate at which molecules strike a given area of the walls decreases.
The pressure decrease is explained by....
a ... I only.
b ... II only.
c ... I and II.
d ... neither I nor II.
The atomic mass number of helium is 4 while that of neon
is 20, and both are monatomic gases. When both gases are at the
same temperature, the ratio of the average speeds of helium atoms
to neon atoms will be....
a ... 1:1
b ... 2.24:1
c ... 5:1
d... 25:1
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.
Two identical containers P and Q hold two different ideal
gasses at the same temperature. The number of moles of each gas
is the same. The molecular weight of the gas in container P is
twice that of the gas in Q.
The ratio of the pressure in P to that in Q will be....
a .... 0.5
b ... 1.0
c ... 1.42
d ... 2.0
The area under the Maxwell-Boltzman speed distribution represents....
a ... the work done by the gas as it expands.
b ... the sum of the speeds of the molecules of the gas.
c ... the internal energy of the gas.
d ... the total number of molecules of the gas.
When the gas in a container increases in temperature the
pressure increases.
Consider the following possible microscopic explanations for this increase.
I The gas molecules colliding with the wall have greater speeds.
II There are more collisions per unit time with the walls of the container.
The best explanation for the pressure increase is provided by....
a ... only explanation I.
b ... only explanation II.
c ... both I and II in conjunction.
d ... neither I nor II.
The blue
curve in each diagram at right represents the Maxwell-Boltzman
distribution of molecular speeds v in a particular sample
of gas at a particular temperature.
In which of the diagrams does the back curve correctly represent the speed distribution when the temperature is increased.
A container holds 1 mole of helium gas (atomic number 4)
mixed with 2 moles of neon gas (atomic number 20). The ratio of
pressure exerted by the helium to that exerted by the neon is....
a ... 1 : 2
b ... 2 : 1
c ... 5 : 1
d ... 1 : 5
When a gas is compressed rapidly by a piston the temperature
of the gas increases because the molecules of the gas ...
a ... bounce off the moving piston with a greater speed than that with which they hit the piston.
b ... are individually compressed.
c ... make more collisions with each other in a given time.
d ... are pushed closer together.