A sample of a liquid isomer X\text{X}X (C4H6O2\text{C}_4\text{H}_6\text{O}_2C4H6O2) was mixed with an excess of oxygen and the mixture ignited. After cooling to the original temperature, the total volume of gas remaining was 425 cm3.
When this gas mixture was passed through aqueous potassium hydroxide, the carbon dioxide reacted and the volume of gas decreased to 145 cm3.
Both gas volumes were measured at 22 ∘C22\text{ }^\circ\text{C}22 ∘C and 101 kPa.
Write an equation for the complete combustion of X\text{X}X in an excess of oxygen and calculate the mass, in mg, of X\text{X}X used.
The gas constant R=8.31 J K−1 mol−1R = 8.31\text{ J K}^{-1}\text{ mol}^{-1}R=8.31 J K−1 mol−1.
79 exam-style questions on AQA A Level Chemistry Amount of substance, covering Relative atomic mass and relative molecular mass, The mole and the Avogadro constant, The ideal gas equation, Empirical and molecular formula, and Balanced equations and associated calculations. Each one has a worked solution and a mark scheme showing where the marks go.