Question

calculate the mass of 12.044*10^25 molecules of oxygen

Answer 1

Hi, consider the answer given below

You need to appreciate the fact that 6.022 x 10^23 molecules of oxigen atom weighs 16g.

Therefore applying this to the calculation of this question we say that

6.022 x 10^23 molecules = 16g

therefore 12.044 x 10^25 molecules is equivalent to what mass

(12.044 x 10^23) x 16/(6.022 x 10^23)

= 3200g

Answer 2

number of mole of oxygen = given number of molecules/Avogadro's number

given number of molecules = 12.044 × 10^25
Avogadro's number = 6.022 × 10²³

so number of mole of oxygen = 12.044 × 10² × 10²³/6.022 × 10²³
= 2 × 10² = 200

now, weight of oxygen = number of mole × atomic mass
= 200 × 16 = 3200g

hence, mass of oxygen = 3200g