Answer :
Let’s analyze the potential energy diagram and the chemical equation given:
[tex]\[ CH_4 + 2 O_2 \Rightarrow 2 H_2 O + CO_2 + 891 \, \text{kJ} \][/tex]
Step-by-Step Solution:
1. Understanding the Reaction:
- The chemical equation shows that methane ([tex]\(CH_4\)[/tex]) and oxygen ([tex]\(O_2\)[/tex]) react to form water ([tex]\(H_2O\)[/tex]) and carbon dioxide ([tex]\(CO_2\)[/tex]), along with a release of 891 kJ of energy.
2. Identifying Energy Change:
- The fact that 891 kJ of energy is added to the products' side of the equation indicates that energy is being released during the reaction.
3. Exothermic vs. Endothermic:
- Exothermic Reaction: When a reaction releases energy to the surroundings, it is termed exothermic. Energy release means the products have lower energy than the reactants.
- Endothermic Reaction: When a reaction absorbs energy from the surroundings, it is termed endothermic. Energy absorption means the products have higher energy than the reactants.
- Since the reaction releases 891 kJ (energy is a product), we can confirm that the reaction is exothermic.
4. Potential Energy of Reactants and Products:
- In an exothermic reaction, the potential energy of the reactants is greater than that of the products. This difference in energy is what is released as heat.
Now, let’s evaluate each statement:
a. The reaction is exothermic:
- True. This is because the reaction releases energy.
b. The reaction is endothermic:
- False. Endothermic reactions absorb energy, whereas this reaction releases energy.
c. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product:
- True. The release of 891 kJ indicates the reaction is exothermic and energy is a product.
d. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are absorbed as a reactant:
- False. Energy would need to be on the reactant side of the equation for it to be absorbed (endothermic reaction), but in this case, it is released.
e. The graph shows that the reactants have greater potential energy than the products:
- True. As the reaction is exothermic, the potential energy of reactants is indeed greater than that of the products, because the energy difference is released as heat.
Summary of True Statements:
- The reaction is exothermic.
- The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product.
- The graph shows that the reactants have greater potential energy than the products.
Thus, the statements that are true about this reaction are:
1. The reaction is exothermic.
2. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product.
3. The graph shows that the reactants have greater potential energy than the products.
[tex]\[ CH_4 + 2 O_2 \Rightarrow 2 H_2 O + CO_2 + 891 \, \text{kJ} \][/tex]
Step-by-Step Solution:
1. Understanding the Reaction:
- The chemical equation shows that methane ([tex]\(CH_4\)[/tex]) and oxygen ([tex]\(O_2\)[/tex]) react to form water ([tex]\(H_2O\)[/tex]) and carbon dioxide ([tex]\(CO_2\)[/tex]), along with a release of 891 kJ of energy.
2. Identifying Energy Change:
- The fact that 891 kJ of energy is added to the products' side of the equation indicates that energy is being released during the reaction.
3. Exothermic vs. Endothermic:
- Exothermic Reaction: When a reaction releases energy to the surroundings, it is termed exothermic. Energy release means the products have lower energy than the reactants.
- Endothermic Reaction: When a reaction absorbs energy from the surroundings, it is termed endothermic. Energy absorption means the products have higher energy than the reactants.
- Since the reaction releases 891 kJ (energy is a product), we can confirm that the reaction is exothermic.
4. Potential Energy of Reactants and Products:
- In an exothermic reaction, the potential energy of the reactants is greater than that of the products. This difference in energy is what is released as heat.
Now, let’s evaluate each statement:
a. The reaction is exothermic:
- True. This is because the reaction releases energy.
b. The reaction is endothermic:
- False. Endothermic reactions absorb energy, whereas this reaction releases energy.
c. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product:
- True. The release of 891 kJ indicates the reaction is exothermic and energy is a product.
d. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are absorbed as a reactant:
- False. Energy would need to be on the reactant side of the equation for it to be absorbed (endothermic reaction), but in this case, it is released.
e. The graph shows that the reactants have greater potential energy than the products:
- True. As the reaction is exothermic, the potential energy of reactants is indeed greater than that of the products, because the energy difference is released as heat.
Summary of True Statements:
- The reaction is exothermic.
- The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product.
- The graph shows that the reactants have greater potential energy than the products.
Thus, the statements that are true about this reaction are:
1. The reaction is exothermic.
2. The equation shows that [tex]$891 \, \text{kJ}$[/tex] of energy are released as a product.
3. The graph shows that the reactants have greater potential energy than the products.
