JC1 AS LEVEL PRACTICE

Which species contains a different number of electrons from the other three?

• Cl

• H₂SO₄

• SO₄^2–

• Te^2–

Which factor causes helium to have a higher first ionisation energy than hydrogen?

• In the 1s orbital in helium, electrons are paired.

• The lowest energy level in helium is filled.

• The nuclear charge in helium is higher than in hydrogen.

• There is less shielding of the outer shell in helium.

A 0.216 g sample of aluminium carbide reacts with an excess of water to produce methane gas. This is the only carbon-containing product formed in the reaction. This methane gas burns completely in O₂ to form H₂O and CO^₂ only. The volume of CO₂ produced at room temperature and pressure is 108 cm3. What is the formula of aluminium carbide?

• Al_²C_³

• Al₃C₂

• Al₃C₄

• Al₄C₃

A reaction between two gases takes place on the surface of the catalytic converter of a petrol-engined car.

In this reaction, four reactant molecules produce three product molecules.

What could be the two reactant gases in this reaction?

• nitrogen and carbon dioxide

• nitrogen monoxide and carbon dioxide

• nitrogen monoxide and carbon monoxide

• nitrogen dioxide and carbon monoxide

An ion contains 1 nitrogen atom and 2 hydrogen atoms. It has an H–N–H bond angle of approximately 105°.

Which pair of number of lone pairs around N in ion and overall charge on ion is correct?

• 1 and +1

• 2 and +1

• 1 and –1

• 2 and –1

Why does ICl (iodine monochloride) have a higher boiling point than Br2?

• because of the difference in the bond energies of the covalent bonds within ICl and Br₂

• because of the difference in the polar nature of ICl and Br₂

• because of the difference in the number of electrons contained within ICl and Br₂

• because of the difference in the relative molecular mass of ICl and Br₂

In this question you may assume that nitrogen behaves as an ideal gas. One atmosphere pressure = 101 kPa.

Which volume does 1.0 g of nitrogen occupy at 50 °C and a pressure of 2.0 atmospheres?

• 70 cm³

• 150 cm³

• 470 cm³

• 950 cm³

Which statement about the properties associated with the different types of bonding involved is correct?

• Any covalent compound that contains both oxygen and hydrogen in its molecule forms hydrogen bonds.

• Ionic bonds and covalent bonds cannot both occur in the same compound.

• Ionic compounds differ from metals in that ionic compounds do not conduct electricity in the solid state.

• The only covalent compounds with high melting points are those in which hydrogen bonds occur.

For which reaction is the enthalpy change an enthalpy change of formation?

• C(g) + 2H₂(g) → CH₄(g)

• 1/2N₂(g) + 1/2O₂(g) → NO(g)

• Na₂O(s) + SO₃(g) → Na₂SO₄(s)

• PCl₃(g) + Cl₂(g) → PCl₅(g)

Two standard enthalpy change of formation values are given.

What is the enthalpy change for the reaction 3VCl₂ → 2VCl₃ + V?

• –210 kJ mol–1

• –121 kJ mol–1

• +121 kJ mol–1

• +210 kJ mol–1