An experiment should be carried out in the fume cupboard if it involves

if you are working with a substances that produce or generate toxic or harmful fumes, vapours, gases, dust or chemical aerosols

it should be carried out in a fume cupboard to eliminate or reduce the risk of exposure to an acceptable and safe level.

- lead + phosphoric acid = hydrogen + lead(ii) phosphate

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3