Hydrogen chloride can be made from the reaction of chlorine and hydrogen: Cl 2 (g) + H 2 (g) → 2 HCl(g) For this reaction, K = 26 × 10 33 and ∆ H = -44 kcal/mol(-184 kJ/mol) at 25 °C. a. Is the reaction endothermic or exothermic?

Hello. And this problem were asked if the change in entropy is equal to negative 129. kilocalories which is negative 543 killed joules per mole. And the equilibrium constant is equal to 1.22 at 25 degrees Celsius. For the formation of phosphorous chloride from the reaction of phosphorous tri chloride and oxygen gas is a reaction exo thermic or endo thermic to determine whether the reaction is exo thermic or endo thermic, we look at the entropy of the reaction Which is negative 129.7, 8 kilocalories per mole since the change in the entropy of the reaction is negative. And sign this tells us that the reaction is eggs are thermic. If we look at a reaction profile diagram, where we have energy on the y axis is a function of the reaction. Progress on the X axis at the beginning, then we have the energy of our reactant. And at the end, we have the energy of our products. So for an exit thermic reaction, our products are lower in energy than the reactant. The change in entropy for the reaction is equal to the difference between the energy of our products and that of our reactant. If the change in entropy is negative, that means then again, that our products are lower in energy than our reactant, which means then that the system lost energy which would be negative and sign. So the answer to this question is the reaction. Eggs are thermic or endo thermic. Again, it is eggs are thermic. This thing corresponds to answer a thanks for watching. Hope this helped.

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7. Energy, Rate and Equilibrium

Endothermic & Exothermic Reactions

GOB Chemistry

7. Energy, Rate and Equilibrium

Endothermic & Exothermic Reactions

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Problem 60a

Textbook Question

Hydrogen chloride can be made from the reaction of chlorine and hydrogen:
Cl₂(g) + H₂(g) → 2 HCl(g)
For this reaction, K = 26 × 10³³ and ∆H = -44 kcal/mol(-184 kJ/mol) at 25 °C.
a. Is the reaction endothermic or exothermic?

Verified step by step guidance

Identify whether the reaction is endothermic or exothermic by analyzing the given enthalpy change (∆H). A negative ∆H value indicates that the reaction releases heat, making it exothermic, while a positive ∆H value would indicate an endothermic reaction.

In this problem, the enthalpy change (∆H) is given as -44 kcal/mol (-184 kJ/mol). Since the value is negative, this means the reaction releases heat.

Recall the definition of an exothermic reaction: it is a reaction that releases energy in the form of heat to the surroundings, resulting in a decrease in the system's enthalpy.

Conclude that the reaction is exothermic because the negative ∆H value confirms that heat is being released during the reaction.

Additionally, note that the large equilibrium constant (K = 26 x 10^33) suggests the reaction strongly favors the formation of products, which aligns with the exothermic nature of the reaction.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Exothermic and Endothermic Reactions

Exothermic reactions release energy, usually in the form of heat, to the surroundings, resulting in a temperature increase. In contrast, endothermic reactions absorb energy from the surroundings, leading to a temperature decrease. The sign of the enthalpy change (∆H) indicates the nature of the reaction: negative values signify exothermic reactions, while positive values indicate endothermic reactions.

Enthalpy Change (∆H)

Enthalpy change (∆H) is a measure of the total heat content of a system during a chemical reaction. It reflects the energy absorbed or released when reactants convert to products. A negative ∆H value, such as -44 kcal/mol in this reaction, indicates that the reaction releases heat, confirming it as exothermic.

Equilibrium Constant (K)

The equilibrium constant (K) quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. A very large K value, like 26 x 10^33, suggests that the products are favored at equilibrium, indicating that the reaction proceeds almost to completion. This can also imply a strong driving force for the reaction, often associated with exothermic processes.