O-Level Combined Science — Chemistry

Question 1

What is the chemical formula for water?

Accepted Answer

H₂O

Answer

HO

Answer

H₂O₂

Answer

OH₂

Question 2

Which type of bond involves the sharing of electrons?

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 3

What is the pH of a neutral solution?

Accepted Answer

7

Answer

0

Answer

14

Answer

1

Question 4

Which gas is produced when an acid reacts with a metal carbonate?

Accepted Answer

Carbon dioxide

Answer

Oxygen

Answer

Hydrogen

Answer

Nitrogen

Question 5

What is the relative atomic mass of carbon?

Accepted Answer

12

Answer

6

Answer

14

Answer

16

Question 6

Which type of reaction releases heat energy to the surroundings?

Accepted Answer

Exothermic

Answer

Endothermic

Answer

Photosynthesis

Answer

Electrolysis