C2: Elements, Compounds and Mixtures

Question 1

Which images contain ONLY molecules?

Answer 1

A, C and D

(B is incorrect as it contains single atoms as well)

Question 2

What is a compound?

Answer 2

A substance made up of atoms of 2 or more different atoms (elements) chemically joined together

Question 3

What is a mixture?

Answer 3

A group of substances that are not chemically bonded together.

Question 4

In which state are the substances shown in the diagrams?

Answer 4

Gas

Question 5

How are properties of the compound H₂O (water) different to the properties of its elements?

Answer 5

H₂ - hydrogen is a gas

O - oxygen is a gas

H₂O - water is a liquid

Question 6

Are the properties of a compound the same as the properties of the elements that make the compound?

Answer 6

No compounds have different properties compared to their elements.

Question 7

Salt is a common compound. What is the chemical name for salt?

Answer 7

Sodium Chloride

(NaCl)

Question 8

Which image shows a compound made from 3 different types of element?

Answer 8

C

Question 9

Which image shows a mixture?

Answer 9

B

Question 10

Which images show compounds?

Answer 10

A and C

Question 11

Compounds containing 2 elements always end in which suffix?

Answer 11

“ide”

e.g. sodium + chlorine –> sodium chloride

Question 12

What is a molecule?

Answer 12

When more than one atom is bonded together.

Question 13

The diagram below shows some particles of a substance at room temperature.

Explain what the diagram tells you about the substance.

Answer 13

• The substance is made up of molecules.
• The substance is in the gas state at room temperature…
• …since its molecules are separate from each other and randomly arranged.
• The substance is a compound…
• …since it is made up of atoms of more than one element.
• One molecule of the substance is made up of one atom of one element and two atoms of another element.

Question 14

Calcium sulfate contains which elements?

Answer 14

Calcium (calcium)

Sulfur (sulf-)

Oxygen (-ate)

Question 15

Iron and chlorine react together to form which compound?

Answer 15

Iron chloride