In the presence of excess oxygen,methane gas burns in a constant-pressure system to yield carbon dioxide and water: (g)+ (g)→ (g)+ O(l)ΔH = -890.0 kJ Calculate the value of q (kJ)in this exothermic reaction when 1.70 g of methane is combusted at constant pressure.

Question

In the presence of excess oxygen,methane gas burns in a constant-pressure system to yield carbon dioxide and water:  (g)+  (g)→  (g)+  O(l)ΔH = -890.0 kJ Calculate the value of q (kJ)in this exothermic reaction when 1.70 g of methane is combusted at constant pressure.

Quizplus · Accepted Answer

First, we need to calculate the moles of methane that are being combusted:

moles CH4 = 1.70 g / 16.04 g/mol = 0.106 mol CH4

Next, we can use the balanced equation to determine the amount of heat released in the reaction:

ΔH = -890.0 kJ/mol CH4 x 0.106 mol CH4 = -94.6 kJ

Since the reaction is exothermic, the value of q will be negative, indicating that heat is being released to the surroundings. Therefore, the best choice is (A) -94.6 kJ.

In the Presence of Excess Oxygen,methane Gas Burns in a Constant-Pressure