Paper 1 - ON 2019 Part 1

Which statement about this distribution curve is correct?

• If the temperature of the gas is increased, the maximum of the curve becomes higher.

• If the temperature of the gas is increased, the maximum of the curve moves to the left.

• The fraction of molecules that react in the presence of a catalyst is shown by ////

• The fraction of molecules that react in the absence of a catalyst is shown by \\\\

In this question it should be assumed that (NH₄)₂CO₃.H₂O_(s) dissolves in water without causing

an increase in volume.

Which mass of (NH₄)₂CO₃.H₂O_(s) should be added to 800 cm³ of water to form a 0.100 mol dm^–3

solution of NH₄⁺ ions?

• 4.56 g

• 7.13 g

• 9.12 g

• 14.3 g

The graph shows the successive ionisation energies of element X and element Y.

Both elements are in Period 3.

Which statement is correct?

• An atom of element X needs one extra electron for a full outer shell; an atom of element Y needs three extra electrons for a full outer shell.

• An atom of element Y has five electrons in the 3p subshell.

• Element X has an oxidation number of +7 in most of its compounds.

• When element X combines with element Y, the bonding is ionic.

Which statement about the electrons in a ground state carbon atom is correct?

• Electrons are present in four different energy levels.

• There are more electrons in p orbitals than there are in s orbitals.

• The occupied orbital of highest energy is spherical.

• The occupied orbital of lowest energy is spherical.

In this question you should assume the vapour behaves as an ideal gas.

0.175 g of a volatile liquid produces a vapour of volume 4.50 × 10^–5 m3 at 100 °C and pressure of 1.013 × 10⁵ Pa.

What is the Mr of the liquid?

• 31.9

• 87.1

• 119

• 127

Which reaction is endothermic?

• Ca(OH)₂(aq) + 2HCl (aq) → CaCl₂(aq) + 2H₂O(l)

• CaCO₃(s) → CaO(s) + CO₂(g)

• 2Ca(s) + O₂(g) → 2CaO(s)

• 2Cl(g) → Cl₂(g)

Which equation correctly represents the standard enthalpy change of atomisation of the given element?

• 1/2 I₂(g) → I(g)

• Na(s) → Na(g)

• Cl₂(g) → 2Cl(g)

• Na(g) → Na⁺(g) + e^–

Look at the picture!

• oxidised: chromium reduced: nitrogen

• oxidised: hydrogen reduced: chromium

• oxidised: nitrogen reduced: chromium

• oxidised: nitrogen reduced: hydrogen

When lead(II) sulfide, PbS, is heated in air, sulfur dioxide and lead(II) oxide are formed.

What is the equation for the reaction between PbS and oxygen?

• PbS + 2O₂ → SO₂ + PbO₂

• PbS + 2.5 O₂ → SO₃ + PbO₂

• PbS + 1.5 O₂ → SO₂ + PbO

• PbS + 2O₂ → SO₃ + PbO

Look at the picture!

• The rate of reaction will decrease and the position of the equilibrium will move to the left.

• The rate of reaction will decrease and the position of the equilibrium will move to the right.

• The rate of reaction will increase and the position of the equilibrium will move to the left.

• The rate of reaction will increase and the position of the equilibrium will move to the right.