What is the amount of substance oxygen o2 weighing 6.4 g?

m (O2) = 6.4 g

To find:
n (O2) -?

1) Using the periodic system of D.I.Mendeleev, calculate the molar mass of oxygen:
M (O2) = Mr (O2) = Ar (O) * N (O) = 16 * 2 = 32 g / mol;
2) Calculate the amount of oxygen substance:
n (O2) = m (O2) / M (O2) = 6.4 / 32 = 0.2 mol.

Answer: The amount of substance O2 is 0.2 mol.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.