posted by krystal .
1-Butene (CH2=CHCH2CH3) burns in the presence of O2 to produce CO2 and H2O. Write the balanced chemical equation for this reaction (omit physical states and use condensed molecular formulas).
This is ok but you omitted the double bond in CH2=CHCH2CH3. The double bond needs to be there (even though it's a condensed formula). When it's omitted the observer doesn't know if it is a double bond or if you just forget and left out the two H atoms.