The equation for the formation of silicon tetrachloride from silicon and chlorine is Si(s) + 2Cl 2 (g) → SiCl 4 (g) + 157 kcal b. Is the energy of the product higher or lower than the energy of the reactants?

Welcome back, everyone. The reaction between silicon and fluorine produces silicon tetra fluoride as shown below, determine whether the energy of the products is lower or higher than that of the reactants. We're going to observe that in our given equation, not only do we have on our product side, our gaseous silicon tetra fluoride as a product, but we also have the figure plus 1615 kilojoules of heat that is released. So we're going to interpret that from this figure. Therefore, we have an exothermic reaction which is defined as a reaction where the energy of our reactant is greater than the energy of our products allowing for a negative entropy change. Negative delta H which describes the heat content of our system being our reaction. And with a negative entropy change, we understand that we have an exothermic process, which is why we next want to recall that for an exothermic reaction, we would observe a bond formation of our products which corresponds to the release of heat and a decrease in energy of our system. But an increase in energy for our surroundings, which corresponds to an increase in temperature of our surroundings. And as we stated earlier, an exothermic reaction is characterized by a negative entropy change due to the fact that the energy of our reactants is greater than the energy of our products. So, based on everything we've outlined, we can determine that because we have an exothermic reaction releasing 1615 kilojoules of heat. Therefore, our energy of our products will be lower than the energy of our reactants. So this is our final answer. I hope this made sense and let us know if you have any questions.

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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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2:25 minutes

Problem 107b

Textbook Question

The equation for the formation of silicon tetrachloride from silicon and chlorine is
Si(s) + 2Cl₂(g) → SiCl₄(g) + 157 kcal
b. Is the energy of the product higher or lower than the energy of the reactants?

Verified step by step guidance

Step 1: Begin by analyzing the given chemical equation: Si(s) + 2Cl₂(g) → SiCl₄(g) + 157 kcal. The '+ 157 kcal' indicates that energy is released during the reaction, meaning it is an exothermic reaction.

Step 2: In an exothermic reaction, the energy of the products is lower than the energy of the reactants because energy is released to the surroundings.

Step 3: The release of 157 kcal signifies that the system loses this amount of energy, which corresponds to a decrease in the energy content of the products compared to the reactants.

Step 4: Conceptually, the energy difference between the reactants and products is what is released as heat (157 kcal in this case). This confirms that the products are more stable and have lower energy.

Step 5: Conclude that the energy of the product (SiCl₄) is lower than the energy of the reactants (Si and Cl₂) due to 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.

Chemical Reaction Energy

In a chemical reaction, the energy of the reactants and products can be compared to determine the reaction's energy change. The energy released or absorbed during a reaction is often expressed in kilocalories or joules. In exothermic reactions, like the formation of silicon tetrachloride, energy is released, indicating that the products have lower energy than the reactants.

Exothermic Reactions

Exothermic reactions are processes that release energy, usually in the form of heat, to the surroundings. This occurs when the total energy of the products is less than that of the reactants, resulting in a negative change in enthalpy. The reaction provided, which produces silicon tetrachloride, is an example of an exothermic reaction, as indicated by the release of 157 kcal.

Enthalpy Change

Enthalpy change (ΔH) is a measure of the total heat content of a system during a chemical reaction. It reflects the difference in energy between the reactants and products. A negative ΔH value signifies that the products are more stable and have lower energy than the reactants, which is the case in the reaction forming silicon tetrachloride, where energy is released.