Question

calculate the number of molecules contained in 0.7kg of oxygen under normal conditions

Answer 1

Answer: 131.73*10^23 molecules

Explanation:

We know that molar mass of oxygen molecule is= 16*2 = 32 g/mol

mass of oxygen given= 0.7 kg = 700g

so, no of moles of oxygen= 700/32 = 21.875 moles

avagadro no= 6.022*10^23

then, we have,

no. of molecules of oxygen= 21.875*6.022*10^23 = 131.73*10^23