Question

I'm asked to find the iron density at 140°C. Can someone help me please

Answer 1

is the same than at STP, 7874 kg per cubic meter, The effect of pressure or temperatures in densities of solids and liquids is really small, you need thousands of degrees to make a significative change in the density of iron.

(This gets really interesting when you wanna know the change in density due to pressure or temperature in a gas)