What is the maximum number of hydrogen bonds that can be formed in a sample containing 1.0 mol (NÅ molecules) liquid HF? Compare with the maximum number that can form in 1.0 mol liquid water.

Explanation:

In one mole of liquid HF , no of molecules is 6.02 x 10²³.

Each molecule forms two hydrogen bonds on an average so no of hydrogen bonds per mol ih HF is

2 x  6.02 x 10²³.

= 12.04 x 10²³ .

In water no of hydrogen bonds per molecule of water is 4 . So in one mole of water no of hydrogen bonds is

4 x 6.02 x 10²³.

= 24.08 x 10²³ .

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.