Question

Question:

Answer 1

Review this chemical equation:

O2 + CH4 yields CO2 + H2O

Which answer best explains what must be done to make this equation comply with the law of conservation of mass? (1 point)

You must add a coefficient of 2 to the oxygen molecule on the left and a coefficient of 2 to the water molecule on the right.
You must add a coefficient of 2 to the methane (CH4) molecule on the left and a coefficient of 2 to the carbon molecule on the right.
You must add a coefficient of 4 to the oxygen molecule on the left and a coefficient of 4 to the water molecule on the right.
You must add a coefficient of 2 to the oxygen molecule on the left and nothing to the molecules on the right.

Answer 2

I don't understand this one :/

Answer 3

hmm.. well if we think about the law of conservation of mass, it basically states that "matter can be changed from one form to another, mixtures can be separated or made, and pure substances can be decomposed BUT the total amount of mass remains constant."

So i guess you just need to "balance the equation":
\[O_{2} + CH _{4} \rightarrow CO _{2} + H _{2}O\]
So first, you want to write down how many atoms of each element you have on each side of the equation.
Like this:

And now, we want to balance this so there are EQUAL atoms of each elements on both sides :)