Introducing chemical reactions test questions - OCR Gateway - GCSE Combined Science Revision

1

What is the correct formula for carbon dioxide?

Co₂

CO2

CO₂

2

Water is produced when hydrogen reacts with oxygen. Which of these shows a balanced equation for this reaction?

2H₂ + O₂ → 2H₂O

2H₂ + O₂ → H₂O

H₂ + 2O₂ → 2H₂O

3

What is the state symbol for a solid?

(s)

(l)

(g)

4

What is the empirical formula of C₄H₈O₂?

CH₂O

C₂H₄O

C₈H₁₆O₄

5

3.0 g of carbon reacts with excess oxygen to form 11.0 g of carbon dioxide. What mass of oxygen reacted?

14.0 g

8.0 g

You cannot say from the information given

6

What is the relative formula mass of calcium carbonate, CaCO₃? (Relative atomic masses: Ca = 40.1, C = 12.0, O = 16.0)

100

68.1

100.1

7

Iron(III) oxide contains Fe³⁺ ions and O^2- ions. What is its formula?

Fe₃O₂

Fe₂O₃

FeO

8

Sodium nitrate contains Na⁺ ions and NO₃^- ions. What is its formula?

Na(NO₃)

Na₃NO

NaNO₃

9

Which of these is a balanced ionic equation? - Higher

Pb²⁺ + Cl^- → PbCl

Pb²⁺ + 2Cl^- → PbCl₂

Pb⁺ + 2Cl^- → PbCl₂

10

Which of these is a balanced half equation? - Higher

4OH^- → 2H₂O + O₂ + 4e^-

4OH^- → H₂O + O₂ + 4e^-

4OH^- → 2H₂O + O₂ + e^-