Question

Number of Hydrogen atoms in $0.2$ moles of ${H_2}S{O_4}$ [ Avogadro’s No = $6\,\, \times \,{10^{23}}$ ]

Answer 1

Just try to recall the concepts of mole concept and Avogadro no. and then try to understand how you can calculate the number of particles like atoms/molecules from a given sample. And a simple method is to find the number of Hydrogen atoms in $1$ mole of sample and then calculate for the required number of moles.

Complete step-by-step solution: Step 1: Analyze the number of atoms per molecule of a sulphuric acid.
One sulphuric acid ( ${H_2}S{O_4}$ ) molecule has 2 hydrogen atoms, 1 sulfur atom, and 4 oxygen atoms.
Step 2: Now, use the number obtained in the previous step to obtain the number of mole of different atoms in one mole of the sulphuric acid.
You can also say one mole of sulfuric acid has 2 moles of hydrogen atoms, 1 mol of sulphur atoms, and 4 moles of oxygen atoms.
Step 3: Recall the Value of Avogadro constant and what is its relation with the mole.
How much is a mol? That's Avogadro's constant = $6\,\, \times \,{10^{23}}$ .
So now, since in 1 mole of Sulphuric acid, there are 2 mole of Hydrogen atoms.
Hence, in 0.2 moles of Sulphuric acid, the number of Hydrogen atoms = $2\, \times \,0.2$ moles = $2\, \times \,0.2\, \times \,6\, \times \,{10^{23}}$ = $2.4\, \times \,{10^{23}}$atoms.

Hence the required answer is, Number of H-atoms = $2.4\, \times \,{10^{23}}$atoms.

Note: The number of entities present in one mole is equal to the Avogadro Number. Avogadro’s number is a similar concept to that of a dozen or a gross. A dozen molecules is $12$ molecules. A gross of molecules is $144$ molecules. Avogadro’s number is $6\,\, \times \,{10^{23}}$ molecules. With Avogadro’s number, scientists can discuss and compare very large numbers, which is useful because substances in everyday quantities contain very large numbers of atoms and molecules.