How much heat is necessary to change 30 g of water at 40°C into water at 80°C?
How much heat is necessary to change 30 g of water at 50°C into steam at 100°C?
30 g x 1 cal/gm-c x (80-40) c x 4.184 j/cal = 5020.8 j
Second one
.....first you have to warm the water....then convert it to steam
30 g x 4.186 j/gm-c x (100-50 c) + 30 gm x 2260 j/gm = 74079 j