P6: Molecules and matter

What is the definition of density

density is a substances mass per unit volume

what is the equation for density

density (d) = mass (m) / volume (v)

How do you measure the density of a solid object

1. measure the mass using an electronic object

2. to find the volume of a regular solid, measure its dimensions using a ruler

3. use the equation for volume l x w x h then work out the density

4. for the volume of an irregular solid, lower it on a thread into a measuring cylinder partly filled with water. you can work out the volume by the rise in water levels

How do you measure the density of a liquid

1. use a measuring cylinder to measure the volume

2. measure the mass of an empty beaker using the balance

3. remove the beaker and add in your liquid

4. calculate the mass of the liquid by subtracting the mass of the empty beaker from the total mass of the beaker and liquid

what are changes of state examples of

physical changes because no new substances are produced

what is the conservation of mass

when a substance changes state, the number of particles in the substance stay unchanged. so the mass of the substance after the change of state is the same as the mass of the substance before the change of state