At the birthday party in, a student ate a piece of cake (200 Cal). To get an idea of the magnitude of this amount of energy there is in that piece of cake, the student would like to know how much water at 20°C can be brought to 45°C. Calculate the mass of water.
200 "Food" Calories (with capital C) equals 200,000 calories.
Set M C *45 = 200,000 and solve for M (in grams)
C = 1.00 calories/g*C
is the specific heat