In the reaction, 2h2 o2 --> 2h2o, how many hydrogen molecules are needed to produce two water molecules? a. 1b. 2c. 3d. 4

b. 2

There are necessary 2 hydrogen molecules to produce 2 water molecules.

Explanation:

The balanced equation is already given:

So, 2 molecules of diatomic hydrogen react with 1 molecule of diatomic oxygen to obtain 2 water molecules.

As you can see in the attached image, the 2 molecules of diatomic hydrogen have 2 hydrogen atoms each (i.e. 4 hydrogen atoms), the molecule of diatomic oxygen has 2 oxygen atoms and the 2 water molecules have 2 hydrogen atoms and 1 oxygen atom each (i.e. 4 hydrogen atoms and 2 oxygen atoms)

1.solid

2.carbon dioxide

3.helium