Heat gained or absorbed in a system can be calculated by multiplying the given mass to the specific heat capacity of the substance and the temperature difference. It is expressed as follows:
Heat = mC(T2-T1)
We calculate as follows:
212 J = 12.8 (0.91)(ΔT)
ΔT = 18.20 K
The increase in temperature is about 18.20 Kelvin.