What type of reaction is represented by the previous two examples?
1) Mg(s) + ½O2(g) → MgO(s) + 146 kcal/mole
2) H2(g) + ½O2(g) → H2O(g), ΔH = -57.82 kcal/mole

are they both exothermic or endothermic?

Question

What type of reaction is represented by the previous two examples?
1) Mg(s) + ½O2(g) → MgO(s) + 146 kcal/mole
2) H2(g) + ½O2(g) → H2O(g), ΔH = -57.82 kcal/mole

are they both exothermic or endothermic?

anonymous · Answer

1st ia endothermic and 2nd is exothermic reaction

anonymous · Answer

that's what I thought but they can't be different because I only have those options for BOTH of them, thank you though!

anonymous · Answer

delta H for 1st rxn is +ve which mean it absorb energy, so its endothermic. delta H of 2nd rxn is -ve which mean it releases energy or heat so will be exothermic rxn.

anonymous · Answer

the answer is exothermic i made and 100 on my chemistry test

aaronq · Answer

^ is right. the answer is exothermic for both, note that in the first equation the heat produced is on the products side.

anonymous · Answer

both reactions are exothermic

anonymous · Answer

Oh sorry... I didn't see that thanku @aaronq  :)

anonymous · Answer

thank you all! :)