In the presence of excess oxygen,methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l) △H = -890.0 kJ
Calculate the value of q (kJ) in this exothermic reaction when 1.80 g of methane is combusted at constant pressure.

Question

Quizplus · Accepted Answer

1. First, we need to calculate the amount of heat released when 1.80 g of methane is burned. We can use the balanced chemical equation and the given enthalpy change to do this:

- 1 mole of CH4 produces -890.0 kJ of heat
- The molar mass of CH4 is 16.04 g/mol

Using these values, we can set up the following proportion to find the amount of heat released when 1.80 g of CH4 is burned:

(1.80 g CH4) / (16.04 g/mol) x (-890.0 kJ/mol) = -100.1 kJ

Note that the negative sign indicates that the reaction is exothermic and releases heat.

2. Therefore, the correct answer is A) -100.1 kJ.

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