# Consider the reaction shown:

452 kcal + 4 PCl5 (s) �¨ P4 (s) + 10 Cl2(g)
This reaction is ________ because the sign of ƒ¢H is ________.
A) exothermic; neither positive nor negative
B) endothermic; positive
C) endothermic; negative
D) exothermic; positive
E) exothermic; negative

14 years ago

14 years ago

8 months ago

## To determine whether the reaction is exothermic or endothermic, we need to look at the sign of ∆H (enthalpy change).

In this reaction, the given enthalpy change is 452 kcal. Since kcal is a unit of energy, a positive value for ∆H indicates that energy is absorbed during the reaction, making it endothermic.

B) endothermic; positive

7 months ago

## To determine whether the given reaction is exothermic or endothermic, you need to determine the sign of the enthalpy change (ΔH). Here's how you can do that:

1. In the given reaction, the enthalpy values are given in kcal (kilocalories). However, to determine the sign of the enthalpy change, we need to compare the energy of the reactants to the energy of the products.

2. The reactants of the given reaction have a total energy of 452 kcal (kilocalories). In comparison, the products consist of solid phosphorus (P4) and gaseous chlorine (Cl2). Both solid and gaseous forms have lower energy compared to the reactants.

3. Since the total energy of the products is lower than the energy of the reactants, this indicates that energy has been released or given off during the reaction. In other words, the reaction is exothermic.

4. Therefore, the answer is: A) exothermic; neither positive nor negative.

Explanation: The given reaction is exothermic because it releases energy, as indicated by the fact that the enthalpy change (ΔH) is negative (since energy is being given off, the sign of ΔH is negative). However, from the options provided, there is no specific mention of the sign of ΔH, which means the answer is "neither positive nor negative."

🤔 🤔 Ask a New Question 🤔 🤔