Question

C5H12(g) + 8 O2(g) → 5 CO2(g) + 6 H2O(g) From this equation, How can I tell the types of bonds broken and formed and the number of bonds there are formed and broken in order to determine if this is endothermic or exothermic reaction? No other information is given.

Answer 1

C5H12 --> identify tyupe of alkane/ene/yne

for alkanes n = C and 2n+2 = H

if n = 5; then 2*5+2 = 12... this must be an alkane

therefore there are only single bonds between C-C and C-H

then

O2 is a diatomic molecule, has a double bond

the bonds being broken are those of O2 and C-C / C-H

the final bonds

C=O from CO2 and O-H of water

since they are plenty of molecules, assume this is exothermic, meaning it realeased energy from breaking O=O and C-C bondings

NOTE: this is a combustion reaction, so by definition, this is exothermic