How many molecules of molecular oxygen react with four molecules of NH3 to form four molecules of nitrogen monoxide and six molecules of water?

5 molecules of O2 reacted.

Explanation:

From the question, were told that 4 molecules of NH3 reacted with O2 to form 4 molecules of NO and 6 molecules of water. To know the molecules of O2 that reacted, we must generate a balanced equation. This is illustrated below:

4NH3 + O2 —> 4NO + 6H2O

From the above equation, we have a total of 10 atoms of O2 on the right side of the equation and a total of 2 atoms of O2 on the left side. To balance the equation, put 5 in front of O2 as shown below:

4NH3 + 5O2 —> 4NO + 6H2O

Now, the equation is balanced.

From the balanced equation, 5 molecules of O2 reacted.

We need 5 molecules of molecular oxygen

Explanation:

Step 1: Data given

molecular oxygen = O2

nitrogen monoxide = NO

water = H2O

Step 2: The balanced equation

4NH3 + O2 → 4NO + 6H2O

Step 3:

On the left side we hace 2x O (in O2), on the right side we have 10x O ( 4x in NO and 6x in 6H2O). To balance the amount of O on both sides, we have to multiply O2 (on the left side) by 5.

4NH3 + 5O2 → 4NO + 6H2O

We need 5 molecules of molecular oxygen

it is b that is the answer.