5. The heat of fusion of lead is 25 J/g and its melting point is 601 K. How much heat is given off as 3.0 g of liquid lead solidifies at 601 K?

the heat given off is 75 J.

Explanation:

Given;

latent heat of fusion of lead, L= 25 J/g

mass of liquid lead, m = 3.0g

The heat given off is calculated as;

H = Lm

Where;

H is the quantity of heat given off

H = 25 x 3

H = 75 J.

Therefore, the heat given off is 75 J.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.