Consider the following reaction: 2Mg(s) + O2(g) → ...

Question

Consider the following reaction: 2Mg(s) + O₂(g) → 2MgO(s) ΔH = -1204 kJ

How many grams of MgO are produced during an enthalpy change of -238 kJ?

How many kilojoules of heat are absorbed when 40.5 g of MgO(s) is decomposed into Mg(s) and O2(g) at constant pressure?

Jules Bruno · Accepted Answer

The given thermochemical equation is:2 Mg(s) + O2(g) → 2 MgO(s)        ΔH = –1204 kJPart A. We are asked to determine the mass in grams of MgO that are produced during an enthalpy change of -238 kJ.[readmore]From the reaction: 2 moles of MgO correspond to –1204 kJ of heat. The molar mass MgO → 40.31 g/mol-238 kJ×2 mol MgO-1204 kJ×40.31 g MgO1 mol MgO=15.9 g MgOThus, the mass of MgO produced when the enthalpy change is -238 kJ is 15.9 g MgO.Part B. Determine the amount of heat absorbed when 40.5 g of MgO(s) is decomposed into Mg(s) and O2(g) at constant pressure.The given reaction would be reversed. → Sign ΔH would be reversed too2 MgO(s) → 2 Mg(s) + O2(g)        ΔH = 1204 kJFrom the reaction: 2 moles of MgO correspond to –1204 kJ of heat. The molar mass MgO → 40.31 g/mol40.5 g MgO×1 mol MgO40.31 g MgO×1204 kJ2 mol MgO=604.8 kJThus, the amount of heat needed to decompose 40.5 g of MgO is 604.8 kJ.

Problem: Consider the following reaction: 2Mg(s) + O2(g) → 2MgO(s) ΔH = -1204 kJHow many grams of MgO are produced during an enthalpy change of -238 kJ? How many kilojoules of heat are absorbed when 40.5 g of MgO(s) is decomposed into Mg(s) and O2(g) at constant pressure?

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Problem Details

Problem: Consider the following reaction: 2Mg(s) + O2(g) → 2MgO(s) ΔH = -1204 kJHow many grams of MgO are produced during an enthalpy change of -238 kJ? How many kilojoules of heat are absorbed when 40.5 g of MgO(s) is decomposed into Mg(s) and O2(g) at constant pressure?

FREE Expert Solution

Problem Details

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