Question

Dimethyl ether, a useful organic solvent, is prepared in two steps. In the first step, carbon dioxide and hydrogen react to form methanol and water: CO2(g) + 3H2(g) → CH3OH (l) + H2O(l) =ΔH−131.kJ In the second step, methanol reacts to form dimethyl ether and water: 2CH3OH (l) → CH3OCH3(g) + H2O (l) =ΔH8.kJ

Calculate the net change in enthalpy for the formation of one mole of dimethyl ether from carbon dioxide and hydrogen from these reactions.
Round your answer to the nearest kj

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Answer 1

Given that Step.1 CO2 (g) + 3H2 (g)-CH,OH (1) +H,O(1) AH --131kJ Step.2 2CH,OH (1)-CH,OCH (g) H2O (1) AH2-8.0k Hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiplestages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes. Multiply the reaction.1by the coefficient two 2CH OH 1)- CH,OCH (g) H O (1) AH 8.0kJ 2CO2(g) + 6HCH,OCH (g) 3H,o (1) According to Hess's law of heat of summation, -254kJ