5 SOLIDS, LIQUIDS AND GASES

how to find the density of a regular solid

• measure the solids length, width and heigh with a rules. calculate volume

• use a balance to measure its mass

• divide mass/volume

how to find the density of an irregular solid

• find the volume by submerging the solid in a eureka can filled with water

• the water displaced by the object will be transferred into a measuring cylinder - record volume

• use a balance to measure mass

• divide mass/volume

how does pressure act in gases or liquids

pressure at any point of a solid/liquid at rest acts equally in all directions. in gases and liquids pressure increases with depth.

what happens when a system is heated

the extra energy is transferred into the particles’ kinetic energy stores, making them move faster. when enough of the particles have enough energy to overcome their attraction, a state change occurs

what happens when a liquid evaporates

particles near the surface of a liquid can escape and become gas particles if:

• the particles are travelling in the right direction to escape the liquid

• the particles are travelling fast enough to overcome the attractive forces of the other particles in the liquid

how to obtain temperature-time graph for water

1. fill a beaker with crushed ice and place a thermometer into the beaker

2. using the bunsen burner, gradually heat the beaker full of ice

3. every twenty seconds, record the temperature and current state of ice

4. plot your graph - changes of state temperature will be constant

what is specific heat capacity

the energy required to change the temperature of an object by one degree celsius per kilogram of mass

how to investigate specific heat capacity of a liquid

• measure the mass of the insulating container. the difference in mass is the mass of the water in the container

• place the electric immersion heat and thermometer in the water. connect the electric immersion heater to the joulemeter, connected to a power supply

• measure the temperature of the water, then turn on the power

• when the temperature has increased by ten degrees, switch off the power and record the temperature increase and energy on the joulemeter.

• plug this into the equation

• repeat the experiment 3 times, then calculate an average specific heat capacity

how to investigate specific heat capacity of a solid

• make sure block of material used has 2 holes for the heater and thermometer and wrap it in an insulating layers

• when temperature has increase by 10 degrees, switch off power supply

• wait until temperature has stopped increasing before recording the highest final temperature. record energy off joulemeter.

how do molecules in gases act?

• constant random motion at high speeds

• random motion means they can underrgo sudden changes in motion if they collide with a containers walls/other molecules

• these collisions produce a net force at right angles, increasing the pressure

what is absolute zero?

the temperature at which the molecules in a substance have zero kinetic energy. -273 degrees. the temperature of a gas in kelvins is proportional to the average energy in the kinetic energy stores of its particles

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

the higher the temperature of the gas, the more kinetic energy, the faster the molecules move

what is the relationship between pressure and volume in a gas with constant temperature

• if the gas is compressed, pressure will increase as molecules will hit the container’s walls more frequently, creating a larger overall net force on the walls.

• if the gas is expanded, volume is increased, which decreases the pressure - more distance means less collisions, so a smaller net force exerted on the walls.

what is the relationship between pressure and kelvin temperature in a gas with constant volume

• the hotter the gas, the higher the average kinetic energy

• if a gas is heated up the molecules will travel at higher speed, creating an increase in pressure as more frequent collisions.