Answer :

To calculate the number of molecules in 4.00 moles of [tex]$H_2S$[/tex], we need to use Avogadro's number. Avogadro's number tells us the number of molecules in one mole of a substance. The value of Avogadro's number is approximately [tex]\(6.022 \times 10^{23}\)[/tex] molecules per mole.

Here are the steps to solve the problem:

1. Identify the given quantity:
- Number of moles of [tex]\(H_2S\)[/tex] = 4.00 moles

2. Recall Avogadro's number:
- Avogadro's number = [tex]\(6.022 \times 10^{23}\)[/tex] molecules/mole

3. Calculate the total number of molecules:
- To find the number of molecules, multiply the number of moles by Avogadro's number:
[tex]\[ \text{Number of molecules} = \text{Number of moles} \times \text{Avogadro's number} \][/tex]
- Plugging in the values:
[tex]\[ \text{Number of molecules} = 4.00 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} \][/tex]

4. Perform the multiplication:
[tex]\[ \text{Number of molecules} = 2.4088 \times 10^{24} \, \text{molecules} \][/tex]

So, the number of molecules in 4.00 moles of [tex]\(H_2S\)[/tex] is approximately [tex]\(2.409 \times 10^{24}\)[/tex] molecules.