High School

How many kilojoules of heat are released when 38.6 g of [tex]CH_4(g)[/tex] reacts completely with [tex]O_2(g)[/tex] to form [tex]CH_3OH(g)[/tex] at constant pressure?

Answer :

The following is a balanced reaction equation: 2CH4 + O2 > 2CH3OH

Let us first compute the delta H reaction using the conventional enthalpy of formation numbers.

Delta H rxn = sum of delta Hf product and delta Hf reactant

- [CH3OH *2] = [CH4*2]

= [-201.2 kJ/mol x 2] + [-74.87 kJ/mol * 2]

= -252.66 kJ

As a result, 2 mol CH4 produces -252.66 kJ of heat.

Let us now calculate the 38.8 g CH4

2.42 mol CH4 = 38.8 g CH4 * 1 mol / 16.04 g

-252.66 kJ = 2 mol CH4

2.42 mol = ? kJ

-306 kJ = 2.42kJ * (-252.66 kj) / 2 mol

As a result, the 38.8 g CH4 will produce 306 kJ (-306kJ) of heat.

Because of the exothermic reaction, a negative sign is assigned.

To learn more about an exothermic reaction click here

brainly.com/question/10373907

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