The amount of heat Q needed to increase the temperature of a substance by [tex]\Delta T[/tex] is given by
[tex]Q= m C_s \Delta T[/tex]
where m is the mass of the substance, and [tex]C_s[/tex] is its specific heat capacity.
In our problem, we have:
m=75.0 g
[tex]\Delta T=250^{\circ}C-150^{\circ}C=100^{\circ} C[/tex]
[tex]C_s=0.13 J/g ^{\circ}C[/tex]
so, substituting these numbers, we get the amount of heat needed:
[tex]Q=(75.0 g)(0.13 J/g^{\circ}C)(100 ^{\circ}C)=975 J[/tex]
