Problem: 4Al(s) + 3 O2(g)→2Al2O3(s) q=-3351kJ is ____ and therefore heat is ______ by the reaction.

FREE Expert Solution

Given: 4Al(s) + 3 O2(g)→2Al2O3(s) q=-3351kj

Recall that:

Exothermic reactions

lose energy, releases heat, temperature of the surroundings increases
▪ involves bond formation (for phase change: gas → liquid → solid)
ΔH is negative

Endothermic reactions

gain/requires energy, absorbs heat, temperature of the surroundings decreases
▪ involves breaking bonds (for phase change: solid → liquid → gas)
ΔH is positive


Analyzing process given:

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Problem Details

4Al(s) + 3 O2(g)→2Al2O3(s) q=-3351kJ is ____ and therefore heat is ______ by the reaction.