20cm³ of methane gas was burnt in 20cm³ of oxygen. write a balanced chemical equation for the reaction and determine which of the gases were in excess

CH4 +O2 => CO2 + 2 H2O

None were in excess

Explanation:

Equation for the reaction is,

CH4 + O2 =>CO2 +2 H2O

No of moles of CH4 = (20 /1000)/24 =0.02 /24 = 0.00083

No of moles of O2 =20 /24000 = 0.0083

CH4 : O2 = 1:1

THEREFORE

None of the gases were in excess.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.