Question

How much heat is released when 240 gram of iron cools from 90o
C to 25o
C [ c = 0.452 J/go C]

(a) -7.05 kJ (b) -8.04 kJ
(c) 6.03 kJ (d) -6.07 kJ

Answer 1

Given:

240 gram of iron cools from 90° C to 25° C.

To find:

Amount of heat released?

Calculation:

We will use CALORIMETRY EQUATION as follows:

$\rm \: H = m \times c \times \Delta T$

$\rm \implies\: H = 240 \times 0.452\times(25 - 90)$

$\rm \implies\: H = 240 \times 0.452\times ( - 65)$

$\rm \implies\: H = - 7051.2 \: joule$

$\rm \implies\: H = - 7.05 \:kJ$

• Negative sign indicates that heat is released.

Option a) is correct.