Question

b. If your hot pack used 100 mL of water, determine the number of grams of the solid salt that you would need to add to the water to raise the temperature from 25.0°C to 60.0°C.

Answer 1

Solution:

We first calculate heat required to raise the temperature of water from 25 deg C to 60 ⁰C.

The heat is required that we get from the salt. So we have to equate this heat for the salt as follow

q = m c delta T

we know specific heat of the salt ( CaCl2) = 3.06 J/g ⁰C

And change in T is also same in both. Their sign is different only.

Lets set up equation as follow;