XCO₃ ---------- XO + CO₂

The equation above shows the action of heat on the carbonate salt of metal X.

How many moles of XCO₃ are needed to produced 4.0 g of oxide X?

[Relative atomic mass: C, 12; O, 16; X, 64]

Sulphuric acid used as an electrolyte in a car battery has a concentration of 0.5 mol dm^-3.

How many moles of sulphuric acid is there in 100 cm^3?

Diagram 1 shows the set-up of apparatus for the titration of potassium hydroxide solution with sulphuric acid.

What is the total volume of the mixture in the conical flask at the end point of the titration in Diagram 1if the concentration of sulphuric acid is 1.0 moldm^-3 ?

Which of the following quantities of substance contain 6 x 10²² molecules?

[Relative atomic mass: H, 1; C, 12; O, 16; Avogadro’s Constant: 6 X 10²³ mol ^-1]

I 1.8 g water

II 1.0 g hydrogen gas

III 3.2 g oxygen gas

IV 4.4 g carbon dioxide

The equation below represents the decomposition of hydrogen peroxide solution.

2H₂O_2(aq) ----------- 2H₂O_(l) + O_2(g)

Which of the following are produced when 1 mole of hydrogen peroxide is decomposed completely?

[1 mole of gas occupies 24 dm³ at room condition;

Avogadro’s Constant: 6.0 X 10²³ mol^-1]

I 2 moles of water

II 12 dm³ of oxygen gas

III 3 x 10²³ of oxygen molecules

IV 1.2 x 10²⁴ of water molecules

What is the number of molecules in 1 mole of ammonia, NH₃?

Use the information that the Avogadro constant = 6.0 x 10²³ mol^-1

A compound with formula X₂CO₃ has a relative formula mass of 138. What is the relative atomic mass of X?

Use the information that the relative atomic mass of C = 12 and O = 16.

The equation shows the reaction between sulphuric acid and sodium hydroxide.

H₂SO₄ + 2NaOH ---------- Na₂SO₄ + 2H₂O

What is the volume of 1.0 mol dm^-3 sodium hydroxide solution which can neutralize 25.0 cm³ of 1.0 mol ^-3 sulphuric acid?

3.2 g of cooper(II) oxide powder is reacted with excess dilute nitric acid.

What is the mass of cooper(II) nitrate formed in the reaction?

Use the information that the relative atomic mass of N = 14, O = 16 and Cu = 64.

The diagram shows two balloons filled with oxygen gas and hydrogen gas.

Which of the following statements is true about the two gases?

A hydrocarbon compound is burnt completely in air to form 17.6 g of carbon dioxide gas and 7.2 g of water.

What is the molecular formula of the hydrocarbon compound?

Given that the relative atomic mass of C=12, H=1, O=16.

The picture shows a waste disposal site. The activity of microorganisms in the waste produces methane gas.

What is the mass of methane gas produced?

Given that the relative atomic mass of H=1, C=12, and 1 mol of gas occupies 24dm³ at room temperature and pressure.

5 g of element X reacted with 8 g of elements Y to form a compound with the formula XY₂.

What is the relative atomic mass of element X?

Given that the relative atomic mass of Y=80.

0.12 g of magnesium reacts with excess hydrochloric acid to produced hydrogen gas. Given that the relative molecular mass of H=1, Mg=24, Cl=35.5 and 1 mol of gas occupies 24 dm³ at room temperature pressure.

Which of the following is true about the reaction?

I. Mg + 2H⁺g ------------ Mg²⁺ + H₂

II. Volume of gas released is 120 cm³

III. Mass of the salt formed is 0.30g

IV. This is a redox reaction

In an experiment, the decomposition of 25cm³ of 0.1 mol dm^-3 hydrogen peroxide solution produces oxygen gas.

(In graph I = P & II = Q)

If the experiment is repeated using another solution, which solution will produce curve Q?

The chemical formula for potassium hexacyanoferrate(III) is K₃Fe(CN)₆.

What is its relative formula mass?

[Relative atomic mass of C =12, N=14, K=39 and Fe = 56]

If the Avogadro number is represented by the letter x, what is the number of hydrogen gas particles, H₂, with the molar volume of 24 dm³ mol^-1 at room temperature and pressure?

A dibase acid, H₂J has the concentration of 0.5 mol dm^-3

Letter J is not the actual symbol of the element. What is the volume of potassium hydroxide, KOH, 1.0 mol dm^-3 that can neutralize 25.0cm³ of the H₂J acid solution?

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

CuCO₃ ----------- CuO + CO₂

Which of the following is not true when 1 mol of copper (II) 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.]

Diagram 13 shows neutralization reaction between a strong acid and a strong alkali.

What is the volume of the alkali needed to produced 1·4625 g of salt?

[Relative atomic mass: Na=23, Cl=35·5, H=1, O=16]

Propane burns completely in oxygen according to the equation shown below.

C₃H_{8 (g)} + 5O_{2 (g)} ------------- 3CO_{2 (g)} + 4H₂O _(l)

If 1.0 mole of propane gas is burnt completely, which volume of gaseous product is obtained, measured at room temperature and pressure ?

A mixture containing 1 mole of ethane and 4 mole of oxygen is ignited, in a sealed container at 100⁰ C. The reaction occurring is shown by the equation below.

C₂H_{4 (g)} + 3O_{2 (g)} ----------- 2CO_{2 (g)} + 2H₂O _(g)

What was the total number of moles of gas at the end of the reaction?