Question

How much heat do you need to raise the temperature of 150g of ice from -30c to -15c?

Answer 1

Heat required = mass (g)*specific heat (c)* Temperature change (ΔT)

Given,
mass = 150 g, specific heat = 4.187 J/g.K, ΔT = -15 -(-30 = -15+30 = 15 K

Therefore,

Heat, H = 150*4.187*15 = 9420.75 J

Answer 2

Answer : Heat required is 9418.5 J

Explanation :

Given that,

Mass of the ice, m = 150 g

Initial temperature of the ice, $T_i=-30\ ^0C$

Final temperature of the ice, $T_f=-15\ ^0C$

We know that heat required is given by :

$Q=mc\Delta T$

$\Delta T$ is change in temperature or $\Delta T=T_f-T_i$

c is the specific heat, $c=4.186\ J/g\ ^0C$

$Q=150\ g\times 4.186\ J/g\ ^0C\times (-15-(-30))\ ^0C$

$Q=9418.5\ J$

Hence, this is the required solution.