Question

2H2 + O2=2H2O How many water molecules are created when 32 grams of oxygen react completely with 4 grams of hydrogen?

Answer 1

32 grams of $O_2$ is 1 mole.

4 grams of $H_2$ is 2 moles.

So we have 2 moles of $H_2O$. Each mole has approximately $6 \cdot 10^{-23}$ particles. In 2 moles of water, there are $12 \cdot 10^{-23}$ water molecules.

Answer 2

Answer:

1.2044 * 10^24 molecules

Explanation:

First thing's first. Let's bring out the balanced chemical equation.

So we have;

                                 2H₂      +       O₂               →   2H₂O

Number of moles:    2               :    1                  :    2

Molar mass               2 ( 2 * 1)    :     32 (2 * 16)  :   18 (2 + 16)

Reacting mass        4 ( 2* 2)      :    32 ( 1 * 32)   :   38 (18 * 2)  

Reacting mass = molar mass * number of moles

The number of moles formed when 4 grams of hydrogen reacts with 32 grams of oxygen is 2 moles.

To obtain number of molecules, multiply the number of moles by the Avogadro constant, 6.022 x 10^23.

This means; Number of Molecules = Number of moles * Avogadro's constant

Number of molecules = 2 * 6.022 * 10^23 = 12.044 * 10^23 = 1.2044 * 10^24 molecules