Assuming the human body to be 80% water, the number of molecules of water present in the body of a person, of mass 65 kg, are

Question

Assuming the human body to be 80% water, the number of molecules of water present in the body of a person, of mass 65 kg, are (A) 1.73 × 1016 (B) 17.39 × 1026 (C) 173.9 × 1028 (D) 1.739 × 1051

Tardigrade Admin · Accepted Answer

100 kg of human body contains 80 kg of H2O 65 kg of human body contains = (80/100) × 65 = 52 kg 18 g of H2O contains = N0 molecules 52 × 103 g of H2O contains = (N0/18) × 52 × 103 molecules

Q. Assuming the human body to be $80$ water, the number of molecules of water present in the body of a person, of mass $65 k g$ , are

$1.73 \times 1 0^{16}$

$17.39 \times 1 0^{26}$

$173.9 \times 1 0^{28}$

$1.739 \times 1 0^{51}$

$100$ $k g$ of human body contains $80$ $k g$ of $H_{2} O$
$65$ $k g$ of human body contains $= \frac{80}{100} \times 65 = 52$ $k g$
$18$ $g$ of $H_{2} O$ contains $= N_{0}$ molecules
$52 \times 1 0^{3}$ $g$ of $H_{2} O$ contains $= \frac{N _{0}}{18} \times 52 \times 1 0^{3}$ molecules

Q. Assuming the human body to be 80 water, the number of molecules of water present in the body of a person, of mass 65kg, are

1.73×1016

17.39×1026

173.9×1028

1.739×1051