When 18.5 g of hgo(s) is decomposed to form hg(l) and o2(g), 7.75 kj of heat is absorbed at standard-state conditions. what is the standard enthalpy of formation (δh°f) of hgo(s)? –90.7 kj/mol

The standard enthalpy of formation of HgO is -90.7 kJ/mol.

Explanation:

The reaction between Hg and oxygen is as follows.

From the given,

Molar mass of HgO = 216.59 g/mol

Mass of HgO decomposed = 18.5 g

Amount of heat absorbed = 7.75 kJ

From the reaction,

The standard  enthalpy of formation =

During the decomposition of 1 mol of HgO , 90.7 kJ of energy absorbed.

For the formation of 1 mol of HgO , 90.7 kJ of energy is release

Therefore, the enthalpy of formation of mercury(II)Oxide is -90.7 kJ/mol