Start learning →

CSEE (Form 4) Chemical Formulae and Equations — practice questions

Explore 9 free Chemical Formulae and Equations questions in CSEE (Form 4) Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise Chemical Formulae and Equations with Quill →

Chemical Formulae and Equations questions and exercises with answers

Showing questions 1–9 of 9.

36 g of magnesium combines with 14 g of nitrogen. The simplest formula of the compound is:Read the answer and worked solution →The IUPAC name of $H_2SO_4$ is:Read the answer and worked solution →A student drops zinc into hydrochloric acid and a gas fizzes off. This reaction is a:Read the answer and worked solution →A decomposition reaction is one in which:Read the answer and worked solution →Work out the formulaRead the answer and worked solution →Name the reaction typeRead the answer and worked solution →Balance the zinc reactionRead the answer and worked solution →Name the acid properlyRead the answer and worked solution →Spot the false claimRead the answer and worked solution →

Worked practice questions

36 g of magnesium combines with 14 g of nitrogen. The simplest formula of the compound is:

  1. MgN
  2. $Mg_2N$
  3. $Mg_3N_2$
  4. $MgN_2$
Show answer and solution

Correct answer: C. $Mg_3N_2$

1. Convert each mass to moles using the relative atomic masses, 24 for magnesium and 14 for nitrogen. 2. Magnesium: $\dfrac{36}{24}=1.5$ mol. Nitrogen: $\dfrac{14}{14}=1$ mol. 3. The ratio is $1.5:1$, which as whole numbers is $3:2$. 4. So the formula is $Mg_3N_2$. 5. This agrees with the valencies: magnesium is 2 and nitrogen is 3, and crossing them over gives the same result. _Source: NECTA CSEE 2021 Chemistry 032, Question 1: Multiple Choice, item (iv)_

Open this question →

The IUPAC name of $H_2SO_4$ is:

  1. Sulphuric acid
  2. Hydrogen sulphate
  3. Sulphuric (VI) acid
  4. Dihydrogen sulphate
Show answer and solution

Correct answer: C. Sulphuric (VI) acid

1. The IUPAC system requires the oxidation state of the central atom to be shown. 2. Here the central atom is sulphur, not hydrogen. 3. Working it out: each hydrogen is $+1$ and each oxygen is $-2$, so $2(+1)+S+4(-2)=0$. 4. That gives $S=+6$, written as the Roman numeral VI. 5. The name is therefore sulphuric (VI) acid; calling it hydrogen sulphate treats hydrogen as the central atom. _Source: NECTA CSEE 2021 Chemistry 032, Question 1: Multiple Choice, item (v)_

Open this question →

A student drops zinc into hydrochloric acid and a gas fizzes off. This reaction is a:

  1. combination reaction
  2. displacement reaction
  3. precipitation reaction
  4. decomposition reaction
Show answer and solution

Correct answer: B. displacement reaction

1. Zinc takes the place of hydrogen in hydrochloric acid, pushing the hydrogen out as a gas. 2. One element replacing another in a compound is a displacement reaction. 3. It is also a redox reaction, since zinc loses electrons and hydrogen gains them. 4. A combination reaction would take two reactants and give a single product, which is not what happens here. 5. Precipitation would form a solid, and decomposition would break one reactant into several products. _Source: NECTA CSEE 2021 Chemistry 032, Question 1: Multiple Choice, item (vi)_

Open this question →

How to practise

  1. Choose a Chemical Formulae and Equations question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Chemistry topics

Organic ChemistryAlcohols Phenols EthersAldehydes KetonesAlkenesChemical BondingChemical Bonding and Molecular StructureChemical EquilibriumClassification of Elements