What requires more energy: raising the temperature of 20 g of iron (specific heat = 0.412 j/g/k) by 10 k or raising the temperature of 15 g of gold (specific heat = 0.129 j/g/k) by 15 k ?

Iron
m = 20 grams
c = 0.412 J/(g oK)
t = 10oK

Heat = m * c * delta T
Heat = 20 * 0.412 * 10
Heat = 83.8 Joules.

Gold
The gold uses the same formula
m = 15 grams
c = 0.129
delta t = 15 oK

Heat = 15 * 0.129 * 15
Heat = 29.0 J

The iron requires more heat. (energy) <<< answer