N2 + O2 �¨ 2 NO ƒ¢H = 43.2 kcal
Based on the reaction shown, which statement is true?
A) 43.2 kcal are consumed when 1.00 g of O2 reacts.
B) 43.2 kcal are produced when 1.00 mole of NO is produced.
C) 43.2 kcal are consumed when 1.00 g of N2 reacts.
D) 43.2 kcal are consumed when 1.00 g of NO is produced.
E) 43.2 kcal are consumed when 1.00 mole of O2 reacts.
To determine which statement is true based on the given reaction, we need to understand the meaning of ĢH in the context of the equation.
ĢH (delta H) represents the enthalpy change, which is the heat energy change that occurs during a chemical reaction. It can be positive (endothermic), negative (exothermic), or zero (no heat change).
In this case, the given ĢH value is 43.2 kcal, indicating that 43.2 kilocalories of heat energy are released when the reaction occurs.
Now let's analyze each statement:
A) 43.2 kcal are consumed when 1.00 g of O2 reacts.
This statement is not true. The equation shows that O2 is a reactant, not a product. The enthalpy change is associated with the production of NO, not the consumption of O2.
B) 43.2 kcal are produced when 1.00 mole of NO is produced.
This statement is not true. While it is mentioned that 2 moles of NO are produced, the given enthalpy change of 43.2 kcal does not directly correspond to the production of 1 mole of NO.
C) 43.2 kcal are consumed when 1.00 g of N2 reacts.
This statement is also not true. The equation shows that N2 is a reactant, not a product. The enthalpy change is associated with the production of NO, not the consumption of N2.
D) 43.2 kcal are consumed when 1.00 g of NO is produced.
This statement is correct. Based on the equation, 2 moles of NO are produced, so to calculate the energy consumed when 1.00 g of NO is produced, we need to convert the mass to moles. Then we can use the molar ratio in the equation to determine the energy change. Since NO and N2 have a molar ratio of 2:1, we need to use 0.5 moles of NO (since 1.00 g is less than the molar mass of NO). Therefore, 43.2 kcal are consumed when 1.00 g of NO is produced.
E) 43.2 kcal are consumed when 1.00 mole of O2 reacts.
This statement is not true. The equation does not indicate the consumption of 1.00 mole of O2; rather, it shows the production of NO.
Therefore, the correct answer is D) 43.2 kcal are consumed when 1.00 g of NO is produced.