Question

A 6.13 g sample of an unknown salt (MM = 116.82
g/mol) is dissolved in 150.00 g water in a coffee cup
calorimeter. Before placing the sample in the water, the
temperature of the salt and water is 23.72°C. After the
salt has completely dissolved, the temperature of the
solution is 28.54°C.


If 3.15 x 10J of heat was gained by the solution, what
is the total heat for the dissolution reaction of the 6.13 g
of salt?

Answer 1

Answer:

-3.19x10³ J

Explanation:

Since the surroundings absorbed 3.19 × 10³ J (or 3190 J) of heat, the system, or the dissolution reaction, must have lost the same amount of heat. The heat for the system, then, is -3.19 × 10³ J (or -3190 J). We know this is true because of the first law of thermodynamics, "heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy".