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

1.2044 * 10^24 molecules

Step-by-step 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