What is the specific heat of water?

The specific heat of water is one of the most important values in physics and chemistry. Option A (0.5 kcal/g/°C) is incorrect — 0.5 cal/g/°C (not kilocalorie) is the specific heat of ice. Multiplied by 1000, 0.5 kcal/g/°C would be enormously high and physically meaningless for water. Option B (1 kcal/g/°C) is incorrect — 1 kcal/g/°C = 1000 cal/g/°C, which is not the specific heat of water. The specific heat is 1 cal/g/°C (not kilocalorie). Option C (1 calorie/gram/°C) is CORRECT — the specific heat of water is 1 cal/g/°C. This is the highest specific heat value among all common liquids and most substances. It means that 1 gram of water requires 1 calorie to raise its temperature by 1°C. Water's high specific heat is the reason why: (1) oceans moderate coastal climates, (2) water is used as a coolant in engines, (3) hot water bottles remain warm for long periods. Option D (4 cal/g/°C) is incorrect — 4 is associated with joules (1 cal = 4.186 J), not with the specific heat value in cal/g/°C. The specific heat of water in cal units is 1 cal/g/°C, not 4.