Question

Question #5034d

Answer 1

`Δ_text(c)H = "-1733 kJ/mol"`

Explanation:

Step 1. Write the balanced equation

`"C"_3"H"_8 + "5O"_2 → "3CO"_2 + "4H"_2"O"`

Step 2. Identify the bonds being broken and formed

`color(white)(mmmmmmmmm)"C"_3"H"_8color(white)(mm) + color(white)(l)"5O"_2 → color(white)(l)"3CO"_2 + "4H"_2"O"`
`color(white)(mmmmmmm)"2C-C + 8C-H"color(white)(m) "5O=O" color(white)(m)"6C=O"color(white)(mll) "8O-H"`
`"BE/kJ·mol"^"-1":color(white)(ll)347color(white)(mml)413color(white)(mmll)495color(white)(mlm)745color(white)(mmll)467`

Step 3. Calculate `Δ_text(c)H`

`Δ_text(c)H = sumBE_text(reactants) - sumBE_text(products)`

`Δ_text(c)H = "((2×347 + 8×413 + 5×495) - (6×745 + 8×467)) kJ/mol" = "(6473 - 8206) kJ/mol" = "-1733 kJ/mol"`