The heats evolved in combustion of rhombic and monoclinic sulphur are, respectively, `70960` and `71030cal mol^(-1)`. What will be the heat of conversion of rhomic sulphur to monoclinic?

Options

A. 70960 calories
B. 71030 calories
C. `-70` calories
D. `+70` calories

Answer

To find the heat of conversion of rhombic sulfur to monoclinic sulfur, we can use the heats of combustion provided for both forms of sulfur. The heat of conversion can be calculated using the following formula:

\[ \Delta H_{\text{conversion}} = \Delta H_{\text{combustion (monoclinic)}} - \Delta H_{\text{combustion (rhombic)}} \]

### Step-by-Step Solution:

1. **Identify the heats of combustion:**
- Heat of combustion of rhombic sulfur (\( \Delta H_{\text{combustion (rhombic)}} \)) = 70960 cal/mol
- Heat of combustion of monoclinic sulfur (\( \Delta H_{\text{combustion (monoclinic)}} \)) = 71030 cal/mol

2. **Set up the equation for heat of conversion:**
\[ \Delta H_{\text{conversion}} = 71030 \, \text{cal/mol} - 70960 \, \text{cal/mol} \]

3. **Perform the calculation:**
\[ \Delta H_{\text{conversion}} = 71030 - 70960 = 70 \, \text{cal/mol} \]

4. **Conclusion:**
The heat of conversion of rhombic sulfur to monoclinic sulfur is \( 70 \, \text{cal/mol} \).

### Final Answer:
The heat of conversion of rhombic sulfur to monoclinic sulfur is \( 70 \, \text{cal/mol} \).

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