Question

Which coefficients balance this equation? _CH4 + _O2 -> _CO2 + _H2O A. 1, 1, 1, 1 B. 1, 1, 2, 1 C. 1, 2, 1, 2 D. 2, 1, 2, 1

Answer 1

The answer: C. 1,2,1,2

Answer 2

C. 1,2,1,2 
 
1 CH4+ 2 O2= 1 CO2+ 2 H20.

when balancing, you need to make sure that each side has the same number of each atom. The reason for this is to abide by the law of conservation of mass; essentially you can't have more or less than you put in the equation. 

When you put the coefficients of C. into the equation you have a total of 2 carbon atoms on each side, 4 hydrogen atoms, and 4 oxygen atoms.