1.1. At high temperatures, gaseous cyclopentadiene (C₅H₆) dimerises to form dicyclopentadiene (C₁₀H₁₂) according to the following equation:

2C₅H₆ (g) ⇌ C₁₀H₁₂ (g)

A student places a sample of pure cyclopentadiene into a flask of volume 350 cm³. At a temperature of 150 ^oC, the pressure in the flask is 125 kPa.

Assuming the gas behaves ideally and remains as pure C₅H₆, calculate the amount, in moles, of cyclopentadiene in the flask.

The gas constant, R = 8.31 J K^-1 mol^-1.

Give your answer to 3 significant figures.

1.2. Use your answer from part (a) to calculate the total number of atoms in the flask.

The Avogadro constant, L = 6.022×10²³ mol⁻¹.

1.3. The student compresses the mixture at constant temperature so that the total pressure increases.

State and explain the effect, if any, on the total number of moles of gas in the flask.