Question

How many atoms are in one mole of water?
A. $1.807 \times {10^{24}}$
B. $3.476 \times {10^{ - 2}}$
C. $1.717 \times {10^{ - 2}}$
D. $1.204 \times {10^{24}}$
E. $2.414 \times {10^{ - 1}}$

Answer 1

Hint: We know that, one mole consists of an Avogadro’s number of atoms or molecules which is equal to $6.023 \times {10^{23}}$.

Complete step by step answer:
It is known to us a mole of a substance is defined in three ways that are in terms of mass, number and volume. In terms of number, the amount of a substance that contains an equal number of atoms or molecules as that Avogadro number of an atom or a molecule is said to be one mole. However, in terms of number, the amount of a substance which contains equal number of atoms or molecules as that Avogadro number of an atom or a molecule is said to be one mole. Avogadro’s number is $6.023 \times {10^{23}}$ molecules per mole.
Therefore, we can say that one mole of water contains $6.023 \times {10^{23}}$ molecules of water.
The chemical formula of water is ${{\rm{H}}_{\rm{2}}}{\rm{O}}$. One molecule of water is composed of three atoms, one oxygen atom and two hydrogen atoms. Therefore, the number of atoms present in one mole of water is calculated as shown below.
$\begin{array}{c}
{\rm{Number}}\;{\rm{of}}\;{\rm{atoms}} = 3 \times 6.023 \times {10^{23}}\\
 = 1.8069 \times {10^{24}}\\
 \approx 1.807 \times {10^{24}}
\end{array}$
Hence, we can say that the number of atoms present in one mole of water is $1.807 \times {10^{24}}$.

Thus, the correct option is A.

Note:
As we know that, the chemical formula of a compound gives information about the proportions of constituent atoms. An amount of substance is measured by the unit mole. The number of atoms can be calculated using Avogadro’s number and the number of moles.