How much heat is absorbed/released when 40.00 g of NH₃(g) reacts in the presence of excess O₂(g) to produce NO(g) and H₂O(l) according to the following chemical equation?
4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(l)
H° = 1168 kJ

Question

How much heat is absorbed/released when 40.00 g of NH₃(g) reacts in the presence of excess O₂(g) to produce NO(g) and H₂O(l) according to the following chemical equation?
4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(l)

How much heat is absorbed/released when 40.00 g of NH<sub>3</sub>(g) reacts in the presence of excess O<sub>2</sub>(g) to produce NO(g) and H<sub>2</sub>O(l) according to the following chemical equation? 4 NH<sub>3</sub>(g) + 5 O<sub>2</sub>(g) → 4 NO(g) + 6 H<sub>2</sub>O(l) H° = 1168 kJ A) 685.8 kJ of heat are absorbed. B) 685.8 kJ of heat are released. C) 2743 kJ of heat are absorbed. D) 2743 kJ of heat are released.

H° = 1168 kJ

Quizplus · Accepted Answer

The given value of ΔH° is 1168 kJ, which means that 1168 kJ of heat is absorbed per mole of NH₃ that reacts. We need to find the heat absorbed/released when 40.00 g of NH₃ reacts. First, we need to find the number of moles of NH₃: Molar mass of NH₃ = 14.01 + 1.0079 + 32.06 + 159.8 = 206.877 g/mol Number of moles of NH₃ = 40.00 g / 206.877 g/mol = 0.1933 mol From the balanced chemical equation, we see that 4 moles of NH₃ reacts with 5 moles of O₂. Since O₂ is in excess, we can assume that all 0.1933 mol of NH₃ reacts. Now, we can use the given value of ΔH° to find the heat absorbed: Heat absorbed = ΔH° × number of moles of NH₃ Heat absorbed = 1168 kJ/mol × 0.1933 mol = 225.9 kJ Since heat is absorbed (as indicated by the positive value of ΔH°), the answer is A) 685.8 kJ of heat are absorbed.

How Much Heat Is Absorbed/released When 40