Answer:
1.6x10^-18 gram
Step-by-step explanation:
(5.3 x 10⁻²³ gram/molecule) x (20,000 molecule)
= (5.3 x 10⁻²³ x 2 x 10⁴) gram
= (10.6 x 10⁻²³⁺⁴) gram
= (1.06 x 10⁻²³⁺⁵) gram
= 1.06 x 10⁻¹⁸ gram
We need to find the mass of 20,000 molecules of oxygen. It can be calculated using unitary method. Here, we can multiply 20,000 molecules by the mass of one oxygen molecule.