To solve the problem, we need to calculate the total heat released (H) when 1 kg of steam at 200°C is converted to 1 kg of water at 100°C. This involves two processes: cooling the steam from 200°C to 100°C and then condensing the steam into water at 100°C.
### Step-by-step Solution:
1. **Identify the mass of steam**:
The mass of steam is given as 1 kg, which is equivalent to 1000 grams.
\[
m = 1000 \, \text{g}
\]
2. **Cooling the steam from 200°C to 100°C**:
We will use the formula for heat transfer:
\[
Q_1 = m \cdot S \cdot \Delta T
\]
where:
- \( S \) is the specific heat capacity of steam, given as \( 0.5 \, \text{cal/g°C} \).
- \( \Delta T \) is the change in temperature, which is \( 200°C - 100°C = 100°C \).
Plugging in the values:
\[
Q_1 = 1000 \, \text{g} \cdot 0.5 \, \text{cal/g°C} \cdot 100°C
\]
\[
Q_1 = 1000 \cdot 0.5 \cdot 100 = 50000 \, \text{cal}
\]
3. **Condensing the steam at 100°C to water**:
The heat released during the phase change (condensation) is given by:
\[
Q_2 = m \cdot L
\]
where:
- \( L \) is the latent heat of vaporization, given as \( 540 \, \text{cal/g} \).
Plugging in the values:
\[
Q_2 = 1000 \, \text{g} \cdot 540 \, \text{cal/g}
\]
\[
Q_2 = 540000 \, \text{cal}
\]
4. **Total heat released (H)**:
The total heat released (H) is the sum of the heat released during both processes:
\[
H = Q_1 + Q_2
\]
\[
H = 50000 \, \text{cal} + 540000 \, \text{cal}
\]
\[
H = 590000 \, \text{cal}
\]
5. **Convert to kilocalories**:
Since \( 1 \, \text{kcal} = 1000 \, \text{cal} \):
\[
H = \frac{590000 \, \text{cal}}{1000} = 590 \, \text{kcal}
\]
### Final Answer:
The value of \( H \) is \( 590 \, \text{kcal} \).