Icse chemistry class 10 worksheet- Study of Compounds
1. PERIODIC PROPERTIES
1. Explain why atomic radius generally decreases from left to right across a period.
2. Arrange Na, Mg, Al and Si in increasing order of atomic radius. Explain your answer.
Case Study Question
A student compares four Period 3 elements: Na, Mg, Al and Cl. The atomic size becomes progressively smaller across the period.
(a) What causes the decrease in atomic size?
(b) Which of the four has the highest electronegativity?
(c) Which would form the largest positive ion?
(d) State the general trend of first ionisation energy across a period.
2. CHEMICAL BONDING
1. Using electron-dot structures, explain the formation of magnesium chloride, MgCl₂.
2. Differentiate between an electrovalent bond and a covalent bond with respect to formation and electrical conductivity.
Case Study Question
Compound X has a high melting point and conducts electricity when molten but not when solid. Compound Y has a low melting point and does not conduct electricity in either state.
(a) Identify the likely type of bonding in X and Y.
(b) Explain the electrical conductivity of X.
(c) Give one example of Y.
(d) State why X is brittle.
3. ELECTROLYSIS
1. Describe the electrolysis of molten lead(II) bromide and write the half-equations at both electrodes.
2. Explain the principle of electroplating. Describe how an iron article can be coated with copper.
Case Study Question
A student electrolyses aqueous copper(II) sulphate using copper electrodes.
(a) Which electrode gains mass?
(b) Which electrode loses mass?
(c) Write the cathode half-equation.
(d) Explain why the concentration of CuSO₄ solution remains approximately unchanged.
4. METALLURGY
1. Explain the functions of coke, limestone and hot air in the extraction of iron in a blast furnace.
2. Differentiate between roasting and calcination. Give one chemical equation for each process.
Case Study Question
An ore contains iron(III) oxide mixed with earthy impurities. In a blast furnace, coke and limestone are added.
(a) What is the function of coke?
(b) What is the function of limestone?
(c) What is slag?
(d) Write the equation for the reduction of Fe₂O₃ by CO.
5. HYDROGEN CHLORIDE
1. Describe the laboratory preparation of hydrogen chloride gas from sodium chloride. Write the balanced equation.
2. Explain why hydrogen chloride gas shows acidic properties only in the presence of moisture.
Case Study Question
A jar containing dry HCl gas is connected to a fountain apparatus and water is introduced.
(a) What happens to the water level?
(b) Why is HCl highly soluble in water?
(c) What happens to moist blue litmus?
(d) Write the reaction between HCl and NH₃.
6. NITRIC ACID
1. Describe the oxidising action of concentrated nitric acid on copper. Write the balanced equation and identify the gas evolved.
2. What is aqua regia? State its composition and one important use.
Case Study Question
Copper reacts with concentrated nitric acid and produces a blue solution with brown fumes.
(a) Identify the brown gas.
(b) Why is the solution blue?
(c) Is nitric acid acting as an oxidising agent? Explain.
(d) Write the balanced equation.
7. SULPHURIC ACID
1. Describe the Contact Process for the manufacture of sulphuric acid, mentioning the catalyst and important conditions.
2. Explain the dehydrating action of concentrated sulphuric acid using sugar as an example.
Case Study Question
In a Contact Process plant, SO₂ is converted to SO₃ before the final absorption step.
(a) Name the catalyst.
(b) Write the reversible equation for SO₂ oxidation.
(c) Why is SO₃ not absorbed directly in water?
(d) Name the substance formed when SO₃ is absorbed in concentrated sulphuric acid.
8. ACIDS AND BASES
1. Distinguish between strong and weak acids in terms of ionisation in water. Give one example of each.
2. A solution has [H⁺] = 1 × 10⁻⁴ mol L⁻¹. Calculate its pH and state whether it is acidic or alkaline.
