definitions
what is a pure substance?
give an example
it has only one compound (material)
water, sugar, salt
how many grams are in 1 kilogram?
one thousand
how many states of matter are there?
3
give an example of a physical change
breaking something
why is the amount of water on our planet constant?
Because of the water cycle
what is a heterogeneous mixture?
give an example
we can see the different materials and separate them
salad
how many centimeters are in one meter?
one hundred
this is matter that has a definite shape and volume
a solid
give an example of a chemical change
burning wood
this is when gas changes to a liquid
condensation
what is a homogeneous mixture
give an example
we cannot see the different mixtures
lemonade
How do we measure fruit at the supermarket?
water?
using a scale
using a measuring jug/cylinder
what happens in a chemical change
new matter is formed
this is when liquid changes to a gas
evaporation
what is mass?
the amount matter there is in an object
how do we measure mass?
using scales
describe a gas using the words: definite, shape, volume
a gas does not have a definite shape or volume
what happens in a physical change?
the shape changes but the mass and volume stay the same
this is when liquid changes to a solid
solidification
what is volume?
the amount of matter an object takes up
how do we measure volume?
using measuring jugs and cylinders
give an example of each state of matter
water
ice
water vapour
How can we change matter (2 ways)
chemical changes and physical changes
this is when solid changes to a liquid
melting