Day 1  Day 2  Day 3  Day 4  Day 5  Day 6

Day 1

Question 1

Three elements, X, Y and Z, have electronic configurations as shown.

Which formulae represent compounds that can conduct electricity in the liquid state?

• YZ

• Y2X

• Z2X

• 1, 2 and 3 are all correct

• 1 and 2 only are correct

• 2 and 3 only are correct

• 1 only is correct

Question 2

In this question, all gases can be assumed to behave ideally.

A chemist heats a mixture of nitrogen and oxygen gases in a sealed container at a constant temperature until the mixture reaches a dynamic equilibrium containing N2, O2​​ and NO.

N2​​ + O2​​ ⇌ 2NO

The chemist repeats the experiment at the same temperature using the same initial amounts of N2​​ and O2, but at a much higher pressure.

Which statements about the second experiment at higher pressure are correct?

• At higher pressure, there are more particles per unit volume.

• The composition of the equilibrium mixture does not change.

• There are more collisions per second so equilibrium is reached faster.

• 1, 2 and 3 are all correct

• 1 and 2 only are correct

• 2 and 3 only are correct

• 1 only is correct

Day 2 

Question 1

The mass spectrum of a sample of lithium shows that it contains two isotopes,​​ 6Li and​​ 7Li.

The isotopic abundances are shown in the table.

What is the relative aromic mass of this sample of lithium, given to three significant figures?

• 6.07

• 6.50

• 6.90

• 6.93

Question 2

Ammonia is a colourless gas that is produced by the Haber process.

Which statements about ammonia are correct?

• An ammonia molecule has three bond pairs and one lone pair of electrons.

• If ammonia is bubbles into water the pH of the solution will increase.

• Ammonia gas can be made by warming ammonium sulfate with aqueous hydrochloric acid.

• 1, 2 and 3 are all correct

• 1 and 2 only are correct

• 2 and 3 only are correct

• 1 only is correct

Day 3

Question 1

Solutions containing chlorate(I) ions are used as household bleaches and disinfectants. These solutions decompose on heating as shown.

3ClO-​​ → ClO3-​​ + 2Cl-

Which oxidation state is shown by chlorine in each of these three ions?

Question 2

When K2MnO4​​ is dissolved in water, the following reaction occurs.

aMnO4-​​ + bH2O → cMnO4-​​ + dMnO2​​ + eOH-

What are the values of a and c in the balanced chemical equation?

Day 4

Question 1

Why is the second ionisation energy of sodium larger than the second ionisation energy of magnesium?

• The attraction between the nucleus and the outer electron is greater in Na+​​ than in Mg+.

• The nuclear charge of Na+​​ is greater than that of Mg+.

• The outer electron of Na+​​ is more shielded than the outer electron of Mg+.

• The outer electron of Na is in the same orbital as the outer electron of Mg.

Question 2

Which statement describe the trend in Period 3 between​​ every pair​​ of adjacent elements from sodium to chlorine?

• The atomic radius decreases.

• The 1st ionisation energy decreases.

• The melting point decreases.

• 1, 2 and 3 are all correct

• 1 and 2 only are correct

• 2 and 3 only are correct

• 1 only is correct

Day 5

Question 1

At a temperature of 2500K and a pressure of 1.00 x 10-4​​ Pa a sample of 0.321g of sulfur vapor has a volume of 2.08 x 106​​ m3.

What is the molecular formula of sulfur under these conditions

• S

• S2

• S4

• S8

Question 2

Hydrogen and carbon dioxide gases are mixed at 800K. A reversible reaction takes place.

H2​​ + CO2​​ ⇌ H2O + CO

At equilibrium, the partial pressures of H2​​ and CO2​​ are both 10.0 kPa. Kp​​ is 0.288 at 800K.

What is the partial pressure of CO in the equilibrium mixture?

• 5.37 kPa

• 18.6 kPa

• 28.8 kPa

• 347 kPa

Day 6

Question 1

A reaction involved in the Contact process is shown.

2SO2​​ + O2​​ ⇌ 2SO3​​  ∆H = -197 kJ mol-1

The reaction is investigated at 200 kPa and 700K and the value of the equilibrium constant, Kp, is found to be Y. The reaction is then investigated at 1000 kPa and 700 K and the value of Kp​​ is found to be Z.

Which statement comparing Y and z is correct?

• Y and Z are the same.

• Y is greater than Z.

• Z is 2.2 times greater than Y.

• Z is 5.0 times greater than Y.

Question 2

The elements magnesium and sulfur each form doubly charged ions.

How do the atomic radii and ionic radii of these elements compare?