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:

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.