Question

What is the molar mass of oxygen, O2? (Round to four significant figures only.)

Answer 1

32.00 would be the answer for "what is the molar mass of oxygen, O2. It would be 31.996 but if you round it to four digits is 32.00

Answer 2

If talking about Oxygen molecule then
Its the member of 6th group
15.9994 x 2 = 31.9988 g/mol