Question

4. The heat of

fusion of a
substance is
80 J/g. How
much energy
is required to
melt 25 g of
the
substance?
A. 2J
B. 25 J
C. 80 J
D. 2 kJ

Answer 1

It is 2 KJ

It is because the formula is :

q=m∆Hf

where m is the mass and ∆Hf is the heat fusion.

So, we get:

q=80×25

q=2000J or 2 KJ