Chemistry Quiz 9701_s19_qp_11 Q1-12

The temperature of a sample of an inert gas is increased. What effect does this have on the number of molecules with the most probable energy and on the number of molecules with high energy?

• Both decrease

• Decreases and increases

• Increases and decreases

• Both increase

A sample of element X is analysed using mass spectrometry. What is the relative atomic mass of this sample of element X?

• 114.4

• 113.7

• 114.0

• 114.2

A washing powder contains sodium hydrogencarbonate, NaHCO3, as one of the ingredients. What is the percentage by mass of sodium hydrogencarbonate in the washing powder?

• 24.0%

• 6.0%

• 3.0%

• 12.0%

The outermost electron in an atom of neon occupies a particular orbital. Which row shows the relative energy and type of this orbital?

• Lower or equal energy,

  s orbital

• Higher or equal energy,

  s orbital

• Higher or equal energy,

  p orbital

• Lower or equal energy,

  p orbital

In which species is there a lone pair of electrons?

• CH3+

• CH3-

• CH4

• CH3

When an evacuated tube of volume 400 cm3 is filled with gas at 300 K and 101 kPa, the mass of the tube increases by 0.65 g. What could be the identity of the gas?

• Argon

• Helium

• Krypton

• Neon

Under which conditions will nitrogen behave most like an ideal gas?

• Low temperature, high pressure

• Low temperature, low pressure

• High temperature, high pressure

• High temperature, low pressure

Two reactions and their enthalpy changes are shown.

2C(s) + 2H₂(g) → C₂H₄(g) ∆H^o = +52.2 kJ mol^–1

C₂H₂(g) + H₂(g) → C₂H₄(g) ∆H^o = –175.8 kJ mol^–1

These data can be used to calculate the enthalpy change for the reaction shown.

What is the value of X?

2C(s) + H₂(g) → C₂H₂(g) ∆H^o = X

• -228.0 kJ mol^-1

• +228.0 kJ mol^-1

• -123.6 kJ mol^-1

• +123.6 kJ mol^-1

Ethanedioic acid, HO₂CCO₂H, can be oxidised by KMnO₄ in dilute sulfuric acid.

In this reaction each ethanedioic acid molecule loses two electrons as it is oxidised. A half-equation for this process is shown. HO₂CCO₂H → 2CO₂ + 2H⁺ + 2e^–

How many water molecules are produced when five ethanedioic acid molecules are oxidised by KMnO₄ in dilute sulfuric acid?

• 5

• 8

• 16

• 10

Hydrogen iodide gas decomposes reversibly producing iodine vapour and hydrogen.

2HI(g) ⇌ I₂(g) + H₂(g) ∆H = +12 kJ mol^–1

The position of the equilibrium for this reaction may be altered by changing the external conditions. Which correctly describes the change in position of equilibrium

• No change with increasing pressure and moves to the left with increasing temperature

• No change with increasing pressure and moves to the right with increasing temperature

• Moves to the right with increasing pressure and decreasing temperature

• Moves to the right with increasing pressure and temperature