Calculate the number of H2O molecules in a human body of mass?

Calculate the number of H2O molecules in a human body of mass 55.1 kg. Assume that, on average, water makes up 62% of the mass of a human body. (Use 1.0 u for the atomic mass of hydrogen, and 16.0 u for the atomic mass of oxygen.)

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    4.6 million to the third

    Source(s): science stuff
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  • 4 years ago

    62% of 56.9 kg = 35.3 kg = 35 300 g find the number of mol: 18.0 g = 1 mol of H2O 35 300 g = 1960 mol of H2O find the number of molecules: 1 mol = 6,022 * 10^23 molecules (Avogadro's number) 1960 mol = 1.18 * 10^27 molecules

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  • u.n. o
    Lv 5
    9 years ago

    Mass of water in human body = 55.1kg*0.62 = 34.16 kg of H2O. 1 mole of H2O = 2 + 16 = 18g so there are 3416000g/18g = 1898 moles of water. So total no. of molecules = Avogadro's no. * 1898 = 6.022e23*1898 = 1.143e27 molecules of water.

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