GCE Chemistry 2021
Past Questions
27+ verified 2021 GCE Chemistry practice questions with Worked answers.
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Which of the following pairs of elements have the same number of neutrons?
The first ionization energies (in kJ mol⁻¹) of four successive elements in the same period are: 496, 738, 578, 786. Which of the elements has the lowest first ionization energy because it has a half-f…
An element M has the electronic configuration [Ar] 3d⁶ 4s². Which of the following statements about M is CORRECT?
Which of the following compounds has the highest melting point?
Which of the following best describes an ionic bond?
An element X has the electronic configuration 2, 8, 7. When X reacts with sodium to form a compound, the type of bonding in the compound and the formula of the compound are respectively
25.0 cm³ of 0.200 mol/dm³ sodium hydroxide solution is exactly neutralised by 20.0 cm³ of sulphuric acid solution. What is the concentration of the sulphuric acid? [Equation: $2NaOH + H_2SO_4 \rightar…
Which of the following contains the greatest number of molecules?
A compound contains 40% carbon, 6.67% hydrogen, and 53.33% oxygen by mass. What is its empirical formula? [C = 12, H = 1, O = 16]
A fixed mass of gas occupies 500 cm³ at 27°C and 100 kPa. What volume will it occupy at 127°C and the same pressure?
25.0 cm³ of 0.10 mol dm⁻³ sodium hydroxide solution is exactly neutralised by 12.5 cm³ of a sulphuric acid solution. What is the concentration of the sulphuric acid?
Which of the following is the correct definition of an acid according to the Brønsted-Lowry theory?
A solution has a hydroxide ion concentration of $1 \times 10^{-4}$ mol dm⁻³ at 25°C. What is the pH of the solution?
Which of the following salts will produce an acidic solution when dissolved in water?
A buffer solution is prepared by mixing 0.20 mol of ethanoic acid with 0.20 mol of sodium ethanoate in 1 dm³ of solution. Given that the $\text{p}K_a$ of ethanoic acid is 4.76, what is the pH of the b…
What is the oxidation state of manganese in potassium permanganate, $KMnO_4$?
Which of the following half-equations correctly represents the reaction at the anode during the electrolysis of concentrated sodium chloride solution?
The standard electrode potential of zinc is −0.76 V and that of copper is +0.34 V. What is the standard electromotive force (e.m.f.) of the electrochemical cell formed when these two electrodes are co…
How many moles of electrons are transferred when 1 mole of $Cr_2O_7^{2-}$ is reduced to $Cr^{3+}$ in acidic solution?
The standard enthalpy of combustion of ethanol is −1368 kJ mol⁻¹. How much heat is released when 2.3 g of ethanol is completely burned? [Molar mass of ethanol = 46 g mol⁻¹]
A catalyst increases the rate of a chemical reaction by
Which of the following correctly explains why increasing temperature increases the rate of a chemical reaction?
Ethanol reacts with ethanoic acid in the presence of concentrated H₂SO₄ to produce ethyl ethanoate. This type of reaction is called
Which of the following statements correctly describes the mechanism of the reaction between benzene and bromine in the presence of anhydrous AlBr₃?
a) State four assumptions of the kinetic theory of gases. (4 marks) b) A sample of gas occupies 500 cm³ at a temperature of 27°C and a pressure of 1.5 atm. Calculate the volume the gas would occupy a…
a) (i) Define the term 'rate of reaction'. (ii) State THREE factors that affect the rate of a chemical reaction. b) The following data were obtained for the reaction between hydrogen peroxide (H2O…
a) State Le Chatelier's Principle. (2 marks) b) Consider the following equilibrium reaction: N2(g) + 3H2(g) ⇌ 2NH3(g) ΔH = -92 kJ/mol State and explain the effect of each of the following ch…