Question

Question #9bc2f

Answer 1

The value of `Δ_"r"H°` is -1456 kJ.

Explanation:

The formula for enthalpy of reaction is

`color(blue)(bar(ul(|color(white)(a/a)Δ_rH^° = sumΔ_fH_text(products)^° - sumΔ_fH_text(reactants)^°color(white)(a/a)|)))" "`

`color(white)(mmmmmmmmm)2"CH"_3"OH(g)" + "2O"_2"(g)" → "2CO"_2"(g)" + "4H"_2"O(l)"`
`Δ_text(f)H^°"/kJ·mol"^"-1": color(white)(mm)"-238.4"color(white)(mmmll)0color(white)(mmmm)"-393.52"color(white)(mm)"-285.83"`

∴ `Δ_rH^° = "[2(-393.52) + 4(-285.83) - 2(-238.4)] kJ" = ("-787.04 - 1143.32 + 476.8) kJ = -1453.6 kJ"`