solids liquids and gases

give the equation linking density mass and volume

density = mass/volume

units = kg/m³

how do you measure the density of a regular solid object?

use a balance to measure an object’s mass

use a ruler to measure the object’s volume

density = mass/volume

how do you measure the density of an irregular solid object?

use a balance to measure object’s mass

lower object into known volume of liquid

measure the new volume of liquid or volume of liquid removed from container

density = mass/volume

how do you measure the density of a liquid?

measure the mass of an empty beaker using a balance

measure the mass of beaker now containing liquid

density = mass/volume

give the equation linking pressure force and area

pressure = force / area

units = pascals (N/m²)

how does pressure at any point in a gas or liquid act?

equally in all directions

describe how atmospheric pressure changes with altitude

pressure at a point in a gas or liquids acts in all directions

atmospheric pressure increases as altitude decreases as there is more air above you

atmospheric pressure is 101000 Pa at sea level

describe how pressure changes with depth

pressure at a point in a gas or liquid acts in all directions

pressure increases as depth increases

more liquid above you

give the equation linking pressure difference, height, density and gravitational field strength

pressure difference = height x density x gravitational field strength

how is pressure created by gas in a container?

- Random, rapid movement of gas particles

- Gas particles collide with walls of container

- Exerts small force

- Pressure = Force / Area

what is absolute zero?

- Temperature at which gas particles have no thermal or kinetic energy

- Pressure of gas is therefore zero

- Ѳ273 °C

what is the kelvin scale?

- Temperature scale starting at absolute zero

- Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules

- Unit: Kelvin (K)

- 0 K =Ѳ273 °C

- 0 °C = 273 K

how is Celcius converted to Kelvin?

Add 273

How is Kelvin converted to Celcius?

Subtract 273

Why does the pressure of a gas increase with increased temperature

- Increase in temperature increases average speed of gas particles

- Collisions between walls and particles more frequent

- Collisions between walls and particles are harder, exerting more force

- P=F/A → increased force means increased pressure for same area

State the gas law linking temperature and pressure

- For a fixed mass of gas at constant volume, the pressure is directly proportional to the Kelvin temperature

- p1/t1 = p2/t2

explain why an inflated balloon shrinks when it is placed in a freezer

- Air in balloon cools

- Molecules in balloon slow down (kinetic energy of molecules reduces)

- Pressure inside balloon decreases

- Pressure outside balloon greater than inside

- Resultant force from air compresses balloon

why does the pressure of a gas increase with decreased volume?

- Same number of particles in smaller volume

- Greater frequency of collisions between particles and walls

- Particles exert larger force on wall over same time

- Average force exerted on walls increases

state the gas law linking volume and pressure

- For a fixed mass of gas at constant temperature, the pressure is inversely proportional to the volume

- p₁V₁ = p₂V₂