Elements, Compound & Mixtures

Water (H₂O) and Carbon dioxide (CO₂) are examples of

• elements

• mixtures

• compounds

• none of These

Tungsten (W) and Uranium (U) are examples of

• elements

• mixtures

• compounds

• none of these

Sand and water is a heterogeneous mixture and can be separated by

• magnetism

• sand and water can not be separated

• electricity

• filtration

Which one of the following elements has the symbol C?

• Copper

• Carbon

• Chlorine

• Calcium

How many atoms are there in a molecule of CO₂?

• 4

• 2

• 1

• 3

If a substance consists of more than one type of atom chemically combined, then it is

• a compound

• a molecule

• an element

• a mixture

Which one of the following substances is a compound?

• Oxygen

• Sodium fluoride

• Air

• Iron

Which one of the following statements about compounds is correct?

• The properties of a compound are the same as the properties of the elements of which it is made up.

• At least one of the elements in a mixture must be a gas.

• It is possible to physically separate a compound into the elements that it is made from.

• The elements in a compound are always present in the same ratio.

A compound is a substance that

• is made up of only element.

• contains only metallic elements chemically joined together.

• contains two or more elements physically combined together in a fixed ratio.

• is made up of two or more elements chemically joined together.

Which one of the following four statements is incorrect?

• Water is not an element.

• All elements are solid at room temperature.

• Iron contains only one type of atom.

• The element Mercury is a liquid at room temperature.