5.1-5.22

Question 1

Density eqution

Answer 1

Density= mass/volume (ρ = m/V)

Question 2

Pressure equation

Answer 2

pressure = force / are (p = F/A)

Question 3

Pressure in liquids…

Answer 3

acts equally in all directions as long as the liquid is not moving

Question 4

pressure difference equation

Answer 4

pressure difference = height × density × gravitational field strength (p = h × ρ × g)

Question 5

explain how molecules in a gas have random motion and that they exert a force and
hence a pressure on the walls of a container

Answer 5

Gas molecules have rapid and random motion therefore when they hit the walls of the container they exert a force, pressure = Force / Area

Question 6

Absolute zero

Answer 6

At absolute zero the particles have no thermal energy or kinetic energy, so they cannot exert a force.
Absolute zero = 0 Kelvin = -2730C

Question 7

why an increase in temperature results in an increase in the average
speed of gas molecules

Answer 7

As you increase the temperature of a gas, the kinetic energy of the gas particles increases and so their average speed also increases.

Question 8

The Kelvin temperature of a gas…

Answer 8

is proportional to the average kinetic energy of its molecules

Question 9

relationship between:
* pressure and volume at constant temperature
* pressure and Kelvin temperature at constant volume

Answer 9

As you heat the gas, the kinetic energy of the particles increases, so does their average speed.
This means more collisions per second with the walls, and they exert a larger force on the wall.
This causes in the total pressure being exerted by the particles to rise.
If temperature is constant, the average speed of the particles is constant.
If the same number of particles is placed in a container of smaller volume they will hit the walls of the container more often.
More collisions per second means that the particles are exerting a larger force on the wall over the same time, so average force exerted on the walls has increased.