Balance this equation. if a coefficient of "1" is required, choose "blank" for that box. ch3cho + o2 → co2 + h2o

Step 1: Write Imbalance Equation

                            CH₃CHO  +  O₂    →    CO₂  +  H₂O

Step 2: Balance Carbon Atoms:
                                                 There are 2 carbon atoms at reactant side and one at product side. So multiply CO₂ with 2 to balance them. i.e.

                             CH₃CHO  +  O₂    →    2 CO₂  +  H₂O 

Step 3: Balance Hydrogen Atoms:
                                                      There are 4 hydrogen atoms at reactant side and 2 Hydrogen atoms at product side. So, multiply H₂O by 2 to balance Hydrogen on both sides. i.e.

                    CH₃CHO  +  O₂    →    2 CO₂  +  2 H₂O

Step 4: Balance Oxygen Atoms:
                                                   There are 3 Oxygen atoms at reactant side and 6 Oxygen atoms at product side. In order to balance them multiply O₂ on reactant side by 2.5 (5/2). i.e  

                    CH₃CHO  +  5/2 O₂    →    2 CO₂  +  2 H₂O

Step 6: Eliminate Fraction:
                                         Multiply overall equation by 2 to eliminate fraction. i.e. 

                    2 CH₃CHO  +  5 O₂    →    4 CO₂  +  4 H₂O

The molecules contain like 54 of water