SPM - Chemical Formulae and Equation

Given the formulae for calcium ion is Ca²⁺ and carbonate ion is CO₃^2-. Choose the correct chemical formula of calcium carbonate.

• Ca(CO₃)₂

• CaCO₃

• Ca₂CO₃

• Ca₃(CO₃)₂

Table below shows the percentage by mass of each element in a compound and their relative atomic masses.

What is the empirical formula of the compound?

• CHO

• CHO₂

• CH₂O

• C₂HO

1.04 g of metal M react with 0.48 g of oxygen to form M oxide. Determine the empirical formula of M oxide.

[ relative atomic mass : O = 16 ; M = 52 ]

• MO

• MO₂

• M₂O₃

• M₃O₂

Diagram below shows the set-up of apparatus to determine the empirical formula of magnesium oxide.

Which of the following statement is true for the lifting and closing of the lid quickly and occasionally during heating?

• To avoid the pressure in the crucible dish

• To avoid the crucible dish from cracking

• To avoid the white fumes from escaping

• To avoid water vapour from entering the crucible dish

How many atoms are in C₆H₁₂O₆?

• 17

• 27

• 24

• 41

The following equation represents a reaction.

3H₂ (g) + N₂ (g) → 2NH₃ (g)

What is the relative molecular mass of the product?

[ Relative atomic mass : H=1 ; N=14 ]

• 2

• 17

• 28

• 34

Sodium hydrogen carbonate decompose on heating according to the following equation :

2NaHCO₃ (s) → Na₂CO₃ (s) + CO₂ (g) + H₂O (l)

If 16.8 g of sodium hydrogen carbonate is used, what is the mass of sodium carbonate produced?

[Relative atomic mass : H = 1 ; C = 12 ; O = 16 ; Na = 23]

• 5.3 g

• 10.6 g

• 21.2 g

• 42.4 g

The following equation shows the decomposition reaction of copper(ll) carbonate when heated at room temperature and pressure.

CuCO₃ --> CuO + CO₂

Which of the following is not true when 1 mol of copper(lI) carbonate is decomposed?

[Relative atomic mass: C= 12, O= 16, Cu= 64 and 1 mol of gas occupies the volume of 24 dm³ at room temperature and pressure].

• 1 mol of copper(II) oxide is formed

• 1 molecule of carbon dioxide gas is given off

• 80g of copper(II) oxide is formed

• 24 dm³ of carbon dioxide gas is given off

The diagram shows the chemical equation for a reaction. What are the reactants in this reaction?

• magnesium chloride and water

• magnesium chloride and hydrochloric acid

• magnesium hydroxide and hydrochloric acid

• magnesium hydroxide and magnesium chloride

Which substance have the same number of atoms as 23g sodium? [ RAM: H=1, N=14, O=16, Na=23, Ca=40]

• 14 g of nitrogen gas, N₂

• 18 g of water, H₂O

• 26 g of calcium, Ca

• 32 g oxygen gas, O₂