In an experiment, 0.4 mol of sulphur trioxide gas, SO3 (g) was allowed to dissociate to sulphur dioxide gas, SO2 (g) and oxygen gas, O2 (g) in a 1.00 Litre container and allow to reach equilibrium
at constant temperature. The equation of the reaction is given as follow:
SO3 (g) =SO2 (g) + 1/2O2 (g)
The number of mole of SO3 at equilibrium is 0.32 mol, SO2 is 0.08 mol and O2 is 0.16 mol Sketch
the graph of concentration against the time for this reaction.

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

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.