Question

calculate the number of molecules in 16 g of oxygen gas

Answer 1

molar mass :- mass of the one mol of the substance is called molar mass.

mass of ' O2 ' = 16g

molar mass of ' O2' = (16×2) = 32g/mol
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mass = number of moles × molar mass

number of moles = mass/molar mass

number of moles = 16/32

number of moles = 0.5 mol
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1 mol of any substance contains avogadro number (6.022×10^23) of molecules then,

molecules = number of moles × 6.022×10^23

molecules = 0.5 × 6.022×10^23

molecules = 3.011 × 10^23 " O2" molecules
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Answer 2

Hey mate here is your answer...

Molar mass :- mass of the one mol of the substance is called molar mass.

mass of ' O2 ' = 16g

molar mass of ' O2' = (16×2) = 32g/mol

mass = number of moles × molar mass

number of moles = mass/molar mass

number of moles = 16/32

number of moles = 0.5 mol

1 mol of any substance contains avogadro number (6.022×10^23) of molecules then,

molecules = number of moles × 6.022×10^23

molecules = 0.5 × 6.022×10^23

molecules = 3.011 × 10^23 " O2" molecules