Mixtures, pure and impure substances

Substances which are made of different compounds and elements which are not bonded together are called...

• molecules.

• mixtures.

• compounds.

• atoms.

Sea water is a mixture because...

• sand, water, salt and other substances are not bonded together.

• sand, water, salt and other substances are bonded together.

• sand, water, salt and other substances are difficult to seperate.

• it has a fixed boiling point.

Properties of mixtures do NOT include...

• being made of different amounts of each substance.

• being difficult to seperate.

• varied boiling and melting points.

• fixed boiling and melting points.

Sea water is an impure substance because...

• the amounts of salt, water and sand are always fixed.

• it is difficult to seperate.

• it has varied boiling and melting points.

• fixed boiling and melting points.

We could seperate the substances in sea water by...

• filtration then evapouration.

• filtration only.

• evaporation only.

• being lucky.

We could determine whether a substance was pure or impure water by...

• evaporating it only.

• checking the boiling point only.

• checking the melting point only.

• all of these things.

The most efficient way to determine whether a substance is pure or impure water is to...

• evaporate all of it.

• check the boiling point.

• filter it.

• distill it.

It is easy to seperate a mixture such as sea water as...

• there are bonds between all susbtances.

• there are not bonds between each substance.

• it has a low boiling point.

• it has a high melting point.

The water in sea water is...

• bonded to salt atoms.

• bonded to sand atoms.

• a mixture.

• a compound.

The water molecules are hard to separate because...

• the atoms are held together by bonds and no energy is needed to break these.

• the atoms are not held together by bonds and energy is needed to make these.

• the atoms are held together by bonds and energy is needed to break these.

• the atoms are not held together by bonds and no energy is needed to break these.