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physicsman2

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## Homework Statement

1)The complete combustion of 1.47 g of methanol produces 29.3 kJ of heat. Determine the ΔH° for the reaction and its sign.

CH3OH(l) + 3/2O2(g) → CO2(g) + 2H2O(g)

2) The value of ΔH° for the reaction below is -126 kJ. How much energy is released when 2.00 mol of NaOH is formed in the reaction?

2Na2O2(s) + 2H2O(l) → 4NaOH(s) + O2(g)

## Homework Equations

Dimensional Analysis

## The Attempt at a Solution

1) I know the answer is -638 kJ but I don't know how you can get that answer. I know why it's negative because heat is produced. I think that you first find the molar mass by dividing 1.47g by 32(the molar mass of methanol) and then multiplying that by 29.3, but the units don't make sense. Thanks for any help.

2)I know how to get the answer, but can anyone explain how and why the answer is the answer? Multiply 2 mol NaOH by -(-126kJ/4mol NaOh) to get the answer.