Form 4 Chemistry Revision Questions for 2026 focuses on key topics in chemistry, including empirical formulas, molar concentrations, and reaction equations. It is designed for students preparing for their chemistry exams, providing a comprehensive set of practice questions and problems. Topics covered include calculations involving hydrated salts, acid-base reactions, and gas laws. This resource is essential for students seeking to enhance their understanding and performance in chemistry.

Key Points

  • Includes empirical formula calculations for hydrated salts and compounds.
  • Covers molar concentration problems and reaction equations.
  • Features practice questions on acid-base neutralization and gas laws.
  • Designed for Form 4 students preparing for chemistry examinations.
Maka Hassan
16 pages
Language:English
Type:Past Paper
Chemistry
Maka Hassan
16 pages
Language:English
Type:Past Paper
Chemistry
316
/ 16
MOI GIRLS SCHOOL NAIROBI
CHEMISTRY DEPARTMENT
FORM 4
REVISION QUESTIONS JUNE 2026
NAME…………………………………………………………CLASS…………………………..
ADM NO……………………………..
TEACHER………………………………………………
1. When 94.5g of hydrated barium hydroxide, Ba(OH)
2
.nH
2
O were heated to constant mass, 51.3g of anhydrous
barium hydroxide were obtained. Determine the empirical formula of the hydrated barium hydroxide. (3 mks)
2. An alkanol has the following composition by mass: hydrogen 13.5%, oxygen 21.6% and carbon 64.9%.
Determine the empirical formula of the alcohol (C=12.0; H=1.0) =16.0). (2 marks)
3. 6.84g of aluminium sulphate were dissolve in 150cm
3
of water. Calculate the molar concentration of the
sulphate ions in the solution.
(Relative formula mass of aluminium sulphate is 342) (3 marks)
4. When a hydrated sample of calcium sulphate CaSO
4
.xH
2
O was heated until all the water was lost, the following
data recorded;
Mass of crucible = 30.296 g
Mass of crucible +hydrated salt = 33.111 g Mass of crucible +
anhydrous salt = 32.781 g
Determine the empirical formula of the hydrated salt.
(Relative formula mass of CaSO
4
=136, H
2
O =18). (3 marks)
5. Phosphoric acid is manufactured from calcium phosphate according to the following equation.
Ca
3
(PO
4
)
2
(s) + 3H
2
SO
4
(l) → 2H
3
PO
4
(aq) + 3CaSO
4
(s)
Calculate the mass (in kg) of phosphoric acid that would be obtained if 155 kg of calcium phosphate reacted
completely with the acid
(Ca=40, P=31, S=32, O=16, H=1) (2 marks)
6. In an experiment to determine the percentage of magnesium hydroxide in an anti-acid, a solution containing
0.50 g of the anti-acid was neutralized by 23.0 cm
3
of 0.010M hydrochloric acid. (Relative formula mass of
magnesium hydroxide =58) Determine the:
(a) Mass of magnesium hydroxide in the anti-acid; (2 marks)
(b) Percentage of magnesium hydroxide in the anti-acid. (1 mark)
7. When 8.53g of sodium nitrate were heated in an open tube, the mass of oxygen gas produced was 0. 83g.Given
the equation of the reaction is:
ℎ𝑒𝑎𝑡
2NaNO
3
(s) → 2NaNO
2
(s) + O
2
(g)
Calculate the percentage of sodium nitrate that was converted to sodium nitrite. (Na= 23.0, N
= 14.0, O = 16.0) (3 marks)
8. Aluminium oxide reacts with both acids and bases.
(a) Write an equation for the reaction between aluminium oxide and hydrochloric acid.
(1 mark)
(b) Using the equation in (a) above, calculate the number of moles of hydrochloric acid that would react
completely with 153.0g of aluminium oxide. (Al = 27.0, O= 16.0) (2 marks)
9. The pressure of nitrogen gas contained in a 1 dm
3
cylinder at -196 °C was 10
7
Pascals.
Calculate the:
(a) Volume of the gas at 25 °C and 10
5
Pascals. (1½ marks)
(b) Mass of nitrogen gas. (Molar volume of gas is 24 dm
3
, N = 14.0)
(1 ½ marks)
10. Analysis of a compound showed that it had the following composition:
69.42% carbon, 4.13% hydrogen and the rest oxygen.
(a) Determine the empirical formula of the compound. (C = 12.0, H = 1.0, O = 16.0) (2 marks)
(b) If the mass of one mole of the compound is 242, determine its molecular formula. (1 mark)
11. Use the information in the table below to answer the questions that follow. The letters do not represent the
actual symbols of the elements.
Element
Atomic number
Melting point (°C)
R
S
T
U
V
W
11
12
15
17
18
19
97.8
650.0
44.0
-102
-189
64.0
(a) Give the reasons why the melting point of:
(i) S is higher than that of R; (1 mark)
(ii) V is lower than that of U. (2 marks)
(b) How does the reactivity of W with chlorine compare with that of R with chlorine? Explain. (2 marks)
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End of Document
316

Figures

MOI GIRLS SCHOOL NAIROBI
Mass of porcelain boat = 13.23g
a) Complete the titration table below using the above results (3 marks)

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FAQs

what are the form 4 chemistry revision questions 2026 about

The Form 4 Chemistry Revision Questions 2026 cover a wide range of topics essential for mastering the chemistry syllabus.

  • Empirical formulas and molecular calculations
  • Reactions and equations, including combustion and neutralization
  • Concentration and molarity calculations
  • Properties of gases and their behavior under different conditions
  • Acid-base reactions and titration methods

how to solve empirical formula questions in form 4 chemistry revision questions 2026

To solve empirical formula questions in the Form 4 Chemistry Revision Questions 2026, follow these steps:

  1. Determine the mass of each element in the compound.
  2. Convert these masses to moles by dividing by the atomic mass of each element.
  3. Find the simplest mole ratio between the elements.
  4. Express the ratio as whole numbers to get the empirical formula.

what topics are included in form 4 chemistry revision questions 2026

The Form 4 Chemistry Revision Questions 2026 include various key topics that are crucial for students preparing for their exams.

  • Stoichiometry and calculations involving moles
  • Acids, bases, and pH calculations
  • Thermochemistry and energy changes in reactions
  • Organic chemistry fundamentals
  • Periodic table trends and properties of elements

how to calculate molar concentration in form 4 chemistry revision questions 2026

Calculating molar concentration in the Form 4 Chemistry Revision Questions 2026 involves using the formula:

Concentration (M) = moles of solute / volume of solution in liters

Steps to follow:

  1. Determine the number of moles of the solute using its mass and molar mass.
  2. Measure the volume of the solution in liters.
  3. Divide the number of moles by the volume to find the molarity.

what are the key formulas in form 4 chemistry revision questions 2026

The Form 4 Chemistry Revision Questions 2026 include several key formulas that students should memorize:

  • Molarity (M) = moles of solute / liters of solution
  • Empirical formula = simplest whole number ratio of elements
  • PV = nRT (Ideal Gas Law)
  • pH = -log[H+]
  • Percentage yield = (actual yield / theoretical yield) x 100%

how to approach titration problems in form 4 chemistry revision questions 2026

To approach titration problems in the Form 4 Chemistry Revision Questions 2026, follow these guidelines:

  1. Identify the reactants and products involved in the reaction.
  2. Write the balanced chemical equation.
  3. Use the volume and concentration of one solution to find the moles.
  4. Apply stoichiometry to determine the moles of the other solution.
  5. Calculate the concentration if needed.

what is the significance of empirical formulas in form 4 chemistry revision questions 2026

Empirical formulas are significant in the Form 4 Chemistry Revision Questions 2026 because they provide the simplest ratio of elements in a compound.

  • They help in determining the composition of compounds.
  • Empirical formulas are essential for stoichiometric calculations in reactions.
  • They form the basis for understanding molecular formulas and compound structures.

how to determine the percentage composition in form 4 chemistry revision questions 2026

To determine the percentage composition in the Form 4 Chemistry Revision Questions 2026, use the formula:

Percentage composition = (mass of element in 1 mole of compound / molar mass of compound) x 100%

Steps include:

  1. Calculate the molar mass of the compound.
  2. Find the mass of the element of interest in one mole of the compound.
  3. Use the formula to find the percentage.

what are common mistakes in form 4 chemistry revision questions 2026

Common mistakes in the Form 4 Chemistry Revision Questions 2026 include:

  • Incorrectly balancing chemical equations.
  • Miscalculating moles and concentrations.
  • Confusing empirical and molecular formulas.
  • Not converting units properly (e.g., cm³ to liters).
  • Overlooking significant figures in calculations.

how to prepare for form 4 chemistry revision questions 2026

To prepare effectively for the Form 4 Chemistry Revision Questions 2026, consider the following strategies:

  • Review key concepts and formulas regularly.
  • Practice past paper questions to familiarize yourself with the exam format.
  • Join study groups to discuss challenging topics.
  • Utilize online resources and revision guides for additional support.
  • Take timed practice tests to improve your time management skills.