Grade 7

When salt is mixed into water it becomes

• element

• compound

• mixture

• solute

Alloys include

• steel

• brass

• bronze

• all of them

In clean air, percentage of oxygen is

• 0.07

• 0.1

• 0.15

• 0.17

Balloons are filled with

• carbon dioxide

• oxygen

• helium

• nitrogen

Constituents of an element can be separated through

• experiment

• physical processes

• physical method

• physical means

A process in which liquid changes into vapor or gas by boiling, is called

• distillation

• filtration

• evaporation

• fractional distillation

Air is a mixture of

• elements

• compounds

• gases

• molecules

The crystals of dry ice that keep things cold are a solid state of

• carbon dioxide

• oxygen

• helium

• nitrogen

Breakdown or formation of compound involves

• chemical reaction

• heating

• passing electricity through

• all of the above

A substance which is made by mixing two elements without being chemically combined is called a

• solute

• compound

• mixture

• solution