# P1.3 - Pressure Flashcards

why do balloons expand when air is blown into it? (3)

- gases move quickly in all directions
- so, they collide with the surface of the ballon
- each collision produces a force
- so, when more air is blown, more force is applied to the balloon causing it to expand

how does temp affect gas pressure? (3)

- particles gain more kinetic energy (1)
- causes more frequent collisions (1)
- makes more force on surface (1)
- more pressure

what is the unit of pressure?

Pa (Pascals)

what is the unit of force?

N (newtons)

what is the unit of area/surface area?

m^2 (meters squared)

what is the equation to work out pressure

force / area

(force over area)

what is extrapolating?

- basically ‘estimating’ what the result would be on a graph

(shown as a dotted line) - an extended dotted line downwards

what can you use to measure the pressure of a gas?

a manometer

what can you use to measure the pressure of air that is trapped in a bottle?

a pressure gauge

explain why it is dangerous to throw a canister full of pressurised gas in a fire? (3)

- the gas particles heat up (1)
- increasing the pressure within the can
- start moving quickly in all directions, exert a high force on the surface area of the canister (1)
- if canister is unable to width stand the force, it would explode (1)

explain the extent to which pressure is, or is not proportional to the temperature of a gas

- temp and pressure have a directly proportional relationship as long as the volume is constant
- the pressure of gas also depends on its volume as well as its temperature

State the direction of the force of a gas on the surface of a container

90 degrees (right angle)

If pressure is increased (within a closed system) how does the volume change?

- and explain the relationship (name)

The volume decreases

INVERSELY PROPORTIONAL

What is the equation for pressure and volume?

+ explain why

Pressure(Pa) x volume (m^3) = constant

+ since pressure and volume are inversely proportional, if you half one the other doubles, and so their product would always equal to the same amount

In terms of the particles why are pressure and volume inversely proportional?

- if you half the volume, the number of collisions per second between the gas particles and container doubles

Vice versa. If you double volume, the number of collisions per second halves