Question

An unknown substance has a mass of 11.9 g . When the substance absorbs 1.071×102 J of heat, the temperature of the substance is raised from 25.0 ∘C to 45.0 ∘C . What is the most likely identity of the substance?

Answer 1

Answer: The most likely identity of the substance is iron.

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 absorbed=$1.071\times 10^2$ Joules

m= mass of substance = 11.9 g

c = specific heat capacity = ?

Initial temperature of the water = $T_i$ = 25.0°C

Final temperature of the water = $T_f$  = 45.0°CChange in temperature ,$\Delta T=T_f-T_i=(45-25)^0C=20^0C$

Putting in the values, we get:

$1.071\times 10^2=11.9\times c\times 20^0C$

$c=0.45J/g^0C$

The specific heat of 0.45 is for iron and thus the substance is iron.