Question

Assume that the human body contains 80% h2o. calculatd the number of molecules of h2o that are in the body of a person who has a man of 65kg

Answer 1

Human body contains 80 % $H_{2}O$

Number of molecules of $H_{2}O$:

65 kg body mass×$\frac{1000 g}{1kg}$×$\frac{80 gH_{2}O}{100 g body mass}$×$\frac{1mol H_{2}O}{18 g H_{2}O}$×$\frac{6.022*10^{23} molecules}{ 1 mol H_{2}O}$

=1.74 x $10^{27}$ molecules $H_{2}O$

Answer 2

How many molecules of o2 are in 8.0 g of oxygen? If the o2 molecules we're completely split into O (oxygen atoms),  how many mole of atome of oxygen would be obtained?