P6 Molecules and matter

Which equation links density, mass and volume?

Density = mass/volume

What can the particle model b used to explain?

The different states of matter and differences in density

If more particles are added to a space, what happens to the density?

More particles = higher density

Why do some objects float in water but some don’t?

Objects that are less dense than water float, objects that are more dense than water sink

How do you measure mass of a regular object?

Using scales

How do you measure volume of a regular object?

Use a millimetre ruler to measure length, width and height

How do you measure mass of an irregular object?

Using scales

How do you measure volume of an irregular object using a measuring cylinder?

Add some water to the measuring cylinder and measure the starting volume of water. Place your irregular object into the measuring cylinder, making sure its submerged. Take it out and measure the water left in the measuring cylinder. Volume = how much the water level changed

How do you measure volume of an irregular object using a eureka can?

Place an empty measuring cylinder under the eureka can spout. Fill the eureka can until water drips out, after the drips stop, empty your measuring cylinder then submerge your object into the beaker. Measure the volume of water in the measuring cylinder. Volume of water = volume of object

How do you measure mass of a liquid?

Using scales

How do you measure volume a liquid?

Use a measuring cylinder and read off the lowest point on the meniscus

What are key features of a solid particles?

They vibrate around a fixed point, held together in a regular pattern by strong forces, solids are dense and can’t be compressed easily, solids have the lowest energy.

What are key features of liquid particles?

They are close together but randomly arranged, the attractive forces between them are weaker than solids but stronger than gases, liquids are dense and can’t be compressed, a liquid can change its shape but not its volume.

Why can a liquid flow?

The particles can move past each other

What are key features of gas particles?

They have very weak forces and gas particles are far apart, gases can be compressed so have no fixed volume, the particles move at a range of speeds in random directions, gases are low density, gases have the most energy

Define internal energy

The total kinetic and potential energy of all the particles that make up a system

Define kinetic energy

The energy the particles have due to their movement

Define potential energy

the energy the particles have due to the space between them

What does heat do to the energy stored within a system?

Heat increases the energy of the particles, either raising the temperature or changing the state of the system

If the temperature of a system increases, what does the increase in temperature depend on?

the mass of the substance heated, the type of material and the energy input to the system

What is the equation for change in thermal mass?

mass x specific heat capacity x temperature change

Define specific heat capacity of a substance

The amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius

Define specific latent heat

the amount of energy needed to change the state of one kilogram of the substance with no change in temperature

What is the equation for the energy for a change of state?

mass x specific latent heat

What is specific latent heat of fusion?

Change of state from a solid to a liquid

What is specific latent heat of vaporisation?

Change of state from a liquid to a gas (vapour)

True or false: The molecules of a gas are in constant random motion

True

Wha tis the temperature of a gas related to?

the average kinetic energy of the molecules

What can happen to a gas when pressure changes?

A gas can be compressed or expanded

What is the equation for the constant?

constant = pressure x volume

What is work?

the transfer of energy by a force

True or false: Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas

True

What does boils law state?