Question

Which statement is True? A) Breaking a chemical bond releases energy. B) When energy is absorbed, the reaction is said to be endothermic and â†H is negative (–). C) Bond dissociation energies are always positive numbers. D) The stronger the bond, the lower its bond dissociation energy. 2. Based on the reaction, N2 + O2 → 2 NO â†H = 43.2 kcal which statement is true? A) 43.2 kcal are consumed when 14.00 g of N2 reacts. B) 43.2 kcal are produced when 1.00 g of O2 reacts. C) 43.2 kcal are produced when 1.00 mole of O2 reacts. D) 43.2 kcal are consumed when 2.00 moles of NO is produced.

Answer 1

Answer :

1) The correct option is, (A) Breaking a chemical bond releases energy.

2) The correct option is, (D) 43.2 Kcal are consumed when 2.00 moles of NO is produced.

Explanation for 1 :

Statement A is correct, because when the chemical bonds are breaking then the some amount of energy releases.

Statement B is incorrect, because when the energy is absorbed then the reaction is said to be endothermic and $\Delta H$ will be positive not negative.

Statement C is incorrect, because the bond dissociation energy are always negative number not positive number.

Statement D is incorrect, because the stronger the bond, the more its bond dissociation energy not lower.

Explanation for 2 :

The given reaction is,

$N_2+O_2\rightarrow 2NO$

The value of $\Delta H = +43.2Kcal$

When the value of $\Delta H$ is positive then the energy is consumed.

From the given reaction we conclude that

43.2 Kcal are consumed when 1 mole of $N_2$ is reacted.

43.2 Kcal are consumed when 1 mole of $O_2$ is reacted.

43.2 Kcal are consumed when 2.00 moles of NO is produced.

Therefore, the correct option is, 43.2 Kcal are consumed when 2.00 moles of NO is produced.