Answer
94.8 kJ
Work Step by Step
From the thermochemical equationwe see that:
2 CH3OH --> 2 CH4 + O2 $\Delta H = +252.8 kJ$
This means that for every 2 moles of CH3OH that react, we have 252.8 kJ that are transferred. We are given that 24g decompose, so we need to convert these to moles. To do this we need the molar mass, which we find as follows:
C has a mass of 12g/mol
H has a mass of 1 g/mol, 4*1 = 4
O has a mass of 16 g/mol
CH3OH has a mass of 32 g/mol
We have 24g so to convert this to moles we have:
24g * (1mol/32g) = 0.75 mol.
Given that 2 moles transfer 252.8kJ, we have:
0.75 mol * (252.8kJ/2moles) = 94.8 kJ
