Question

a person has weight 60kg he has 18% water in his body how many molecules of water are in his body

Answer 1

Explanation:

person weight =60kg

percentage of water =18 %

=18/100×60

=18/5×3

=54/5

=10.8 kg

Answer 2

Concept:

Avogadro's number, which is equal to 6.02214076 x 10²³, is the quantity of units in one mole of any material (defined as its molecular weight in grams).

The smallest component of a substance that has both its chemical and physical characteristics. One or more atoms make up molecules.

Given:

The weight of a person is 60 kg and has 18% water in his body.

Find:

The number of water molecules in his body.

Solution:

The mass of the body is 60 kg.

The person has 18% water in his body.

Therefore,

The weight of water in his body is $=60\times \frac{18}{100}=10.8kg$ .

Now, 10.8 kg = 108 × 10² g

The chemical formula of water is H₂O.

1 gram of water has $\frac{6.023\times 10^{23}}{18}$ water molecules.

Therefore,

10.8 kg of water will have:

$=\frac{6.023\times 10^{23}}{18}\times 108\times 10^2=36.138\times 10^{25}$ molecules.

The number of water molecules in his body is $36.138\times 10^{25}$ molecules.

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