CAIE A-Level Chemistry AS Mathematical Structural Convention and Data Skills Questions

The model of the nuclear atom was first proposed by Ernest Rutherford. He developed this model on the basis of results obtained from an experiment using gold metal foil.

Tumbaga is an alloy of copper and gold. A sample of tumbaga was analysed. The mass spectrum of the sample is shown.

Calculate the percentage abundance of gold, x, in the sample of tumbaga.

C, D and E are isomers of each other.
They are made by passing an alcohol vapour over an aluminium oxide catalyst.

F is an organic molecule which has the molecular formula $\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{2}$. When F is heated with NaOH(aq) followed by $\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq})$ the products G and H are made.

Separate samples of G and H are added to
- $\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})$
- sodium metal
- alkaline aqueous iodine.

The observations are described in the table.

Draw the structures of G and H.

$4\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO}$ is used in the synthesis of some antibiotics.

X, Y and Z are all isomers of $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO}$.

A summary of some of the reactions and properties of X, Y and Z is shown in the table.

Draw the skeletal formula of Z.

Calcium and its compounds have a large variety of applications.

Calcium ethanedioate is formed when calcium reacts with ethanedioic acid, $\left(\mathrm{CO}_{2} \mathrm{H}\right)_{2}$. The compound contains one cation and one anion.

Draw the displayed formula of the anion present in calcium ethanedioate.