Question #91b45

1 Answer
Feb 2, 2018

9.41 x 1021 molecules

Explanation:

16 grams of Oxygen atom = 1 mole
1 mole = 6.023 x 1023 molecules
16 grams of Oxygen atom have molecules = 6.023 x 1023 molecules
0.25 g of Oxygen atom will have molecules = (6.023 x 1023 molecules) x 0.25 g]/16 g = 9.41 x 1021 molecules

OR
Oxygen = 0.25 g
molar mass = 16 g
no. of moles = 0.2516 = 0.0156 moles

1 mole = 6.023 x 1023 molecules
so, 0.0156 moles of Oxygen atom = 0.0156 moles x 6.023 x 1023 molecules = 9.39 x 1021 molecules = 9.4 x 1021 molecules