IGCSE Stoichiometry Quiz

The equation shows the reaction between magnesium and sulfuric acid.

[Ar: H, 1; O, 16; Mg, 24; S, 32]

Mg + H₂SO₄ → MgSO₄ + H₂

In this reaction, which mass of magnesium sulfate is formed when 6 g of magnesium react with excess sulfuric acid?

• A 8

• B 24

• C 30

• D 60

Two atoms of magnesium, Mg, react with one molecule of oxygen, O₂.

What is the formula of the product?

• A MgO

• B MgO₂

• C Mg₂O

• D Mg₂O₂

Copper(II) oxide reacts with ammonia.

The left hand side of the balanced equation for this reaction is:

3CuO + 2NH3 →

What completes the equation?

• A 3Cu + 2HNO₃

• B 3Cu + 2N + 3H2O

• C 3Cu + N₂ + 3H₂O

• D 3Cu + 2NO + 3H₂O

What is the relative formula mass, M_r, of CaCO₃?

• A 50

• B 68

• C 100

• D 204

A molecule, Z, contains two atoms of oxygen, six atoms of hydrogen and three atoms of carbon.

What is the formula of Z?

• A CH₃CH₂CHO

• B CH₃COCH₃

• C C₂H₅CO₂H

• D C₃H₆CO₂H

Iron forms an oxide with the formula Fe₂O₃.

What is the relative formula mass of this compound?

• A 76

• B 100

• C 136

• D 160

In athletics, banned drugs such as nandrolone have been taken illegally to improve performance.

Nandrolone has the molecular formula C₁₈H₂₆O₂.

What is the relative molecular mass, M_r, of nandrolone?

(Relative atomic mass: H = 1; C = 12; O = 16)

• A 46

• B 150

• C 274

• D 306

The structure of an organic compound, X, is shown.

What is the molecular formula of X?

• A C₆H₉

• B C₆H₁₂

• C C₇H₁₂

• D C₇H1₄

What is the relative molecular mass, M_r, of nitrogen dioxide?

• A 15

• B 23

• C 30

• D 46

A compound contains one atom of calcium, two atoms of hydrogen and two atoms of oxygen.

What is the correct chemical formula of the compound?

• A CaO₂H₂

• B HOCaOH

• C H₂CaO₂

• D Ca(OH)₂