For the following UNBALANCED chemical equation: _____ C2H6(g) + _____ O2(g) → _____ CO2(g) + _____ H2O(g), what are the correct coefficients to balance the equation?

• A. 2 C2H6 + 5 O2 → 2 CO2 + 6 H2O
• B. 1 C2H6 + 2 O2 → 1 CO2 + 2 H2O
• C. 1 C2H6 + 3 O2 → 2 CO2 + 3 H2O
• D. 2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

Answer: (D)

Verified step by step guidance

1. Identify the number of atoms for each element in the reactants and products. For C2H6, there are 2 carbon atoms and 6 hydrogen atoms. For O2, there are 2 oxygen atoms.
2. Start by balancing the carbon atoms. Since there are 2 carbon atoms in C2H6, you need 2 CO2 molecules to balance the carbon atoms, resulting in 4 carbon atoms on the product side.
3. Next, balance the hydrogen atoms. C2H6 has 6 hydrogen atoms, so you need 3 H2O molecules to balance the hydrogen atoms, resulting in 6 hydrogen atoms on the product side.
4. Now, balance the oxygen atoms. You have 4 CO2 molecules, which require 8 oxygen atoms, and 6 H2O molecules, which require 6 oxygen atoms, totaling 14 oxygen atoms needed on the product side.
5. Finally, balance the oxygen molecules. Since each O2 molecule provides 2 oxygen atoms, you need 7 O2 molecules to supply the 14 oxygen atoms required for the balanced equation.