Question

How many molecules are in 3 moles of ${{H}_{2}}S$?

Answer 1

Hint: The answer to this question is based on the fact that one mole of any substance contains Avogadro's number of molecules and multiplying this value to the number of moles will lead you to the required answer.

Complete step by step answer:
In the lower classes of general concepts of chemistry, we have studied about the definition that is given for moles, molecules, atoms and also the Avogadro number or the Avogadro constant.
Now, we shall recall the definitions and thus can obtain the required answer.
- One mole of a substance is the measure of the amount of a substance according to the International System of Units.
- One molecule is the group of atoms bonded together which represents the small fundamental unit of chemical compound.
- An atom is the smallest particle of a chemical that can exist and which combines with the same or other atoms to constitute a molecule.
- Avogadro number is the constant that is the proportionality factor which relates the number of constituent particles in a sample with the amount of the substance in that sample.
- The S.I. unit for this constant value is given as $mo{{l}^{-1}}$ and is defined by the symbol ‘N’ or ${{N}^{0}}$ .
Thus, according to his law, the Avogadro constant is the value which is given for one mole of substance and that is 1 mole = $6.022\times {{10}^{23}}$ .
Now, 1 mole of ${{H}_{2}}S$ contains $6.022\times {{10}^{22}}$ number of molecules.
Therefore, by cross multiplication rule, we can calculate the number of molecules in 3 moles of ${{H}_{2}}S$ .
This is given by 3 moles of ${{H}_{2}}S\times \dfrac{6.022\times {{10}^{23}}}{1}$ .
This gives the value = $1.8\times {{10}^{24}}$ molecules of ${{H}_{2}}S$ .
Therefore, the correct answer is 3 moles of ${{H}_{2}}S$ contains $1.8\times {{10}^{24}}$ number of molecules.

Note: Note that Avogadro’s number or Avogadro’s constant is the unit that may constitute electrons, atoms, ions or molecules which is dependent upon the nature of the substance and also the character of the reaction.