SCS Year 8 Elements, Compounds & Mixtures

Which of the following sets of substances represents mixtures only?

• Blood, seawater and air

• Air, blood and sodium chloride

• Gold, carbon and air

• Orange juice, sodium and hydrogen

How many atoms out there in a molecule of CO₂?

• 4

• 3

• 2

• 2

What is the chemical symbol of the element phosphorus?

• Ph

• F

• Fe

• P

A substance that cannot be split into simpler substances by chemical means is known as

• a molecule

• an element

• a compound

• a mixture

This diagram represents

• a mixture

• a compound

• an element

• an atom

A substance up of only one type of atom is called

• an element

• a compound

• a gas

• a mixture

Which one of the following statements about mixtures is correct?

• The different substances in the mixture are in a definite proportion to each other.

• A mixture is made up of elements chemically combined.

• It is extremely difficult to separate a mixture into different substances.

• A mixture must contain at least two different substances.

Elements are sometimes written with two letters. Magnesium is one of these elements.

What is the symbol for magnesium?

• Mg

• mg

• MG

• mG

How many elements are in CuS0₄?

• 2

• 4

• 3

• 7

How many atoms are in CuSO₄?

• 5

• 6

• 7

• 8