The heat change for the reaction
`C(s)+2S(s)toCS_(2)(l)` is called the heat of

Options

A. Reaction
B. Fusion
C. Formation
D. Combustion

Answer

To determine the heat change for the reaction \( C(s) + 2S(s) \rightarrow CS_2(l) \), we need to identify the type of heat change involved in this reaction.

### Step-by-Step Solution:

1. **Identify the Reaction Components**:
- The reactants are carbon in solid form (C(s)) and sulfur in solid form (S(s)).
- The product is carbon disulfide in liquid form (CS2(l)).

2. **Understanding the Heat Change**:
- The heat change associated with a reaction is often referred to as the "heat of" something. Common terms include heat of reaction, heat of formation, heat of combustion, and heat of fusion.

3. **Definition of Heat of Formation**:
- The heat of formation (ΔH_f) is defined as the heat change that results when one mole of a compound is formed from its elements in their standard states.

4. **Analyzing the Given Reaction**:
- In this reaction, one mole of carbon disulfide (CS2) is formed from its constituent elements (carbon and sulfur) in their standard states.
- Since we are forming CS2 from its elements, this reaction represents the formation of a compound.

5. **Conclusion**:
- Therefore, the heat change for the reaction \( C(s) + 2S(s) \rightarrow CS_2(l) \) is called the heat of formation.

Thus, the correct answer is that the heat change for the reaction is called the **heat of formation**.

### Final Answer:
The heat change for the reaction \( C(s) + 2S(s) \rightarrow CS_2(l) \) is called the **heat of formation**.

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