Question

1. hydrogen and oxygen react to form water. select the answer that correctly shows how many h2, o2 and h2o molecules are needed to balance the equation.

a) 2, 1, 2
b) 1, 1, 2
c) 2, 1, 3
d) 3, 2, 1

1. how do lactic acid and alcohol fermentation differ? * a) lactic acid fermentation can occur in large muscles in the human body, while alcohol fermentation occurs in yeast and some bacteria.

Explanation:

Step1: Write un - balanced equation

$H_2+O_2
ightarrow H_2O$

Step2: Balance oxygen atoms

There are 2 oxygen atoms in $O_2$ on the left - hand side and 1 oxygen atom in $H_2O$ on the right - hand side. To balance oxygen, we put a coefficient of 2 in front of $H_2O$: $H_2 + O_2
ightarrow2H_2O$

Step3: Balance hydrogen atoms

Now, there are 2 hydrogen atoms in $H_2$ on the left - hand side and 4 hydrogen atoms in $2H_2O$ on the right - hand side. To balance hydrogen, we put a coefficient of 2 in front of $H_2$: $2H_2+O_2
ightarrow2H_2O$

Answer:

A. 2, 1, 2