Question

Solve this:
Q). Calculate the mass of 1 molecule of water. 16.26 mg of sample of elements X contains $1.66\times {10}^{20}$ toms. What is the atomic mass?

Answer 1

Dear student,
One mole of water = 18 g = 6.022 * 10²³ molecules
1 molecule = 18/6.022 * 10²³
= 2.98 * 10^-23 g

Now, it is given that
1.66 * 10²⁰ atoms = ( 16.26 *10 ^-3 ) g
Since , 1 mole = 6.022* 10²³ atoms
Hence , 1 mole = ( 16.26 *10 ^-3 ) g * 6.022* 10²³ / 1.66 * 10²⁰
= 58.99g
Regards