The specific heat of carbon is 0.71 j/(g c) how much energy is given off as a 2 gram piece of graphite cools from 120 to 20 c

-142 joules ( or -100 joules when accounting for significant figures)

Explanation:

q = m c delta T

q = (.71)(2)(20 - 120)

q = (.71)(2)(-100)

q = -142 joules

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.

a:

by the combination of an unlimited number of elements