Question
90g water
✓
Answer
Given : Mass of water $\left( H _2 O \right) m =90 g$.
To find: Number of molecules in 90 g of water.
Solution : Molecular mass of $\left( H _2 O \right) M =($ Atomic mass of H $) \times 2+($ Atomic mass of O $) \times 1$
$\therefore$ Molecular mass of $\left( H _2 O \right) M =1 \times 2+16$
$\therefore$ Molecular mass of $\left( H _2 O \right) M =18$
According to the formula,
Number of moles in the given $H _2 O ( n )$
1 mol of $H _2 O$ contains $6.022 \times 10^{23}$ molecules.
5 mol of $H _2 O$ contains $5 \times 6.022 \times 10^{23}$ molecules. $=30.11 \times 10^{23}$ molecules, that is 90 g of $H _2 O$ contains $30.11 \times 10^{23}$ molecules of $H _2 0$.
90 g of water contains $30.11 \times 10^{23}$ molecules of water.
To find: Number of molecules in 90 g of water.
Solution : Molecular mass of $\left( H _2 O \right) M =($ Atomic mass of H $) \times 2+($ Atomic mass of O $) \times 1$
$\therefore$ Molecular mass of $\left( H _2 O \right) M =1 \times 2+16$
$\therefore$ Molecular mass of $\left( H _2 O \right) M =18$
According to the formula,
Number of moles in the given $H _2 O ( n )$
1 mol of $H _2 O$ contains $6.022 \times 10^{23}$ molecules.
5 mol of $H _2 O$ contains $5 \times 6.022 \times 10^{23}$ molecules. $=30.11 \times 10^{23}$ molecules, that is 90 g of $H _2 O$ contains $30.11 \times 10^{23}$ molecules of $H _2 0$.
90 g of water contains $30.11 \times 10^{23}$ molecules of water.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Write the formula : Kinetic energy
Give two examples of : Positive work done
Raj applied a force of 20 N and moved a book 40 cm in the direction of the force. How much was the work done by Raj?
Define : Tropism
Define : Differentiation
Find whether work is positive, negative or zero: Person pushing a car in the forward direction.
Determine the resistance of a copper wire having a length of 1 km and diameter of 0.5 mm.
What is the relationship between newton, meter and joule?
State any four uses of concave mirror.
Which different milk products are obtained at home by fermentation of the cream from the milk?