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) 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.
(a) -94.6 kj
(b) 0.0306 kj
(c) -0.0106 kj
(d) 32.7 kj
(e) -9.46 × 10^4 kj

The energy released will be -94.56 kJ or -94.6 kJ.

Explanation:

The molar mass of methane is 16g/mol

The given reaction is:

the enthalpy of reaction is given as  ΔH = -890.0 kJ

This means that when one mole of methane undergoes combustion it gives this much of energy.

Now as given that the amount of methane combusted = 1.70g

The energy released will be:

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.