Question

Isopropyl alcohol, C3H7OH is an organic compound. It melts at -89 C and boils at 82.6 C. IT has a heat fusion of 88 J/g and a heat of vaporization of 733.33 J/g. The specific heat of liquid isopropyl alcohol is 2.68 J/g-C. The specific heat of its solid form is 12.72 J/g-C. The specific heat of its gaseous form is 1.54 J/g-Cc. Determine the heat necessary to change 70 g of solid isopropyl alcohol at -120 C to gaseous isopropyl alcohol at 82.6 C

Answer 1

Here are the formulas you need for this problem. There are three.
When you are in the same phase (everything is liquid, or gases, or solids, you use
q = mass x specific heat x (Tfinal-Tinitiail). That's equation 1.

When you are at the phase change from solid to liquid use
q = mass x heat fusion. Let's call that equation 2.

When you are at the phase change from liquid to gas use
q = mass x heat vaporization. Let's call that equation 3.

For example, ice at -10 to steam at 120.
q1 = heat needed to move T from -10 as a solid to the melting point, but still a solid, is eqn 1 since you are in the same phase.

q2 = then you melt the solid at zero c to liquid at zero c. equn 2. This is a phase change.

q3 = heat needed to raise T of liquid water at zero C to liquid water at the boiling point of 100 C. Same phase. Eqn 1

q4 = heat needed to change liquid water at 100 to steam at 100. phase change. Eqn 3

q5 = heat needed to change steam at 100 to steam at 120. Same phase. eqn 1

Then total q is sum of q1 through q5.

Post your work if you get stuck.