If you have a balanced equation you can convert between mass and energy using dimensional analysis.

Calculate the heat associated with the decomposition of 1.15g of NO₂(g) according to the equation:

N₂(g) + 2O₂(g) → 2NO₂(g)        ΔH = +67.6 kJ

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Calculate the mass of ethane, C₂H₆, which must be burned to produce 100kJ of heat.

2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l)       ΔH = -3120kJ

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Is this reaction endothermic or exothermic?

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Exothermic, because the ΔH is negative.