B
Compound X is a colourless liquid at room temperature.
(a) A sample of pure X was slowly heated from -5.0°C, which is below its melting point, to 90 °C.
which is above its boiling point. Its temperature is measured every minute and the results are
represented on the graph.
90°C-
temperature
t°℃
-5°C
A
B
с
D
time
E
(i) Complete the equation for the equilibrium present in the region BC.
X(S)X(1)
(ii) What is the significance of temperature t°C?
(iii) What is the physical state of compound X in the region EF?
SHEETS
[1]
(ii) Calculate the empirical formula of X. Show your working.
[1]
[1]
(iv) What would be the difference in the region BC if an impure sample of X had been used?
[1]
Compound X is a hydrocarbon. It contains 85.7% of carbon. The mass of one mole of X is 84 g.
(i) What is the percentage of hydrogen in the compound?
[1]