Question

How many molecules of water (${H_2}O$) are there in 3.50 moles of water (${H_2}O$)?

Answer 1

1 mole of any substance is equal to the value of $6.022 \times {10^{23}}$number of atoms or molecules. As the moles of the water is given, the number of molecules of water can easily be calculated.

Complete step by step answer: Here in this question we have given that the number of moles of water is 3.50 moles.
We need to find the number of molecules of water present in 3.50 moles of water.
As we know that the 1 mole of any substance (described as molecular weight in grams) is equal to the value $6.022 \times {10^{23}}$.
The value $6.022 \times {10^{23}}$is the Avagadro’s number and the constant is known as Avagadro’s constant.
The number of moles of water is calculated as shown below.
$\Rightarrow 3.50 \times 6.022 \times {10^{23}}$
$\Rightarrow 2.1077 \times {10^{24}}$
Therefore, the number of the molecules of water present in 3.50 moles of water is $2.1077 \times {10^{24}}$.

Additional information: The Avagadro’s number is defined as the number of atoms present in 12 g of carbon-12. The value of Avagadro’s number is $6.022 \times {10^{23}}$. It is represented by ${N_A}$. The number of moles is calculated using the Avagadro’s number as shown below.
$Number\;of\;Moles = \dfrac{{Number\;of\;particles}}{{Avagadro\;Number}}$
The number of particles represents the atom or molecule.

Note:
You must be clear about the terms mole and molecule as they are two different terms. Avagadro’s number helps to determine the number of molecules or atoms present in one mole of the substance where the number of molecules can be calculated by dividing the mass (if given) by the molecular weight (determined from the periodic table).