What needs to happen for the equation ch4 + o2 → co2 + h2o to be balanced? a. nothing, the equation is already balanced. b. a coefficient of 2 must be added before the second reactant and the second product. c. a coefficient of 2 must be added before both products and reactants. d. a coefficient of 2 must be added before both products.

B. This is because the Hydrogen and Oxygen need balanced out.

Current-

C-1            |        C-1
H-4            |         H-2
O-2            |         O-3

Adding a coefficient of 2 before oxygen in the reactants and H2O in the products would balance this equation

CH4 + 2O2 → CO2 + 2H2O
C-1            |        C-1
H-4            |         H-4
O-4            |        O-4

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