Specific heat of water is 1 cal `g^(-1) .^(@)C^(-1)`

Explanation

### Step-by-Step Solution

1. **Understanding Specific Heat**:
- Specific heat is defined as the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius (°C).
- For water, this value is 1 calorie per gram per degree Celsius (1 cal/g°C).

2. **Definition of a Calorie**:
- A calorie is a unit of heat energy. It is defined as the amount of heat required to raise the temperature of 1 gram of water by 1°C.

3. **Application of Specific Heat**:
- If you want to calculate the heat energy (Q) required to change the temperature of a certain mass of water (m) by a certain temperature change (ΔT), you can use the formula:
\[ Q = m \times c \times \Delta T \]
- Here, \(c\) is the specific heat capacity of water, which is 1 cal/g°C.

4. **Example Calculation**:
- Suppose you have 100 grams of water and you want to raise its temperature by 5°C. Using the formula:
\[ Q = m \times c \times \Delta T \]
\[ Q = 100 \, \text{g} \times 1 \, \text{cal/g°C} \times 5°C \]
\[ Q = 500 \, \text{cal} \]
- Therefore, you would need 500 calories of heat to raise the temperature of 100 grams of water by 5°C.