Question

How much heat is released when 27.6 g P C l subscript 3 cools from 83.1 °C to 55.6 °C? (The specific heat of P C l subscript 3 is 0.874 J/g °C).

Answer 1

Answer: Thus 663 J of heat  is released when 27.6 g $PCl_3$ cools from 83.1 °C to 55.6 °C

Explanation:

The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

$Q=m\times c\times \Delta T$

Q = Heat released = ?

m = mass of substance = 27.6 g

C = specific heat capacity = $0.874J/g^0C$

Initial temperature= $T_i$ = $83.1^0C$

Final temperature  = $T_f$  = $55.6^0c$

Change in temperature ,$\Delta T=T_f-T_i=(55.6-83.1)^0C=-27.5^0C$

Putting in the values, we get:

$Q=27.6g\times 0.874J/g^0C\times -27.5^0C=-663J$

As the value of q is negative, it means the heat has been released and it is 663J