The amount of heat energy required to increase the temperature of 20 g of water by `1^(@)C` is ______.

Options

A. 10 cal
B. 20 cal
C. 15 cal
D. 2 cal.

Explanation

To find the amount of heat energy required to increase the temperature of 20 g of water by 1°C, we can use the concept of specific heat capacity.

### Step-by-Step Solution:

1. **Understand Specific Heat Capacity**: The specific heat capacity of water is 1 calorie/g°C. This means that to raise the temperature of 1 gram of water by 1°C, 1 calorie of heat energy is needed.

2. **Calculate for 20 grams of Water**: Since we need to raise the temperature of 20 grams of water by 1°C, we can use the formula:
\[ \text{Heat Energy (Q)} = \text{mass (m)} \times \text{specific heat (c)} \times \text{temperature change (ΔT)} \]
Here, \( m = 20 \, \text{g} \), \( c = 1 \, \text{cal/g°C} \), and \( ΔT = 1°C \).

3. **Substitute the Values**: Plugging in the values we have:
\[ Q = 20 \, \text{g} \times 1 \, \text{cal/g°C} \times 1°C \]

4. **Calculate the Heat Energy**:
\[ Q = 20 \, \text{calories} \]

5. **Final Answer**: Therefore, the amount of heat energy required to increase the temperature of 20 g of water by 1°C is **20 calories**.