How many molecules of ethane are present in 64.28 liters of ethane gas (C2H6) at STP
Use the Ideal Gas Law
\(PV = nRT\)
\((1.00atm)(64.28L) = n(.08206L*atm*mol^{-1}*K^{-1})(273.15K)\)
n = 2.8677moles
\(2.8677mol* \frac{6.022*10^{23}molecules}{1mol}\)
\(= 1.727*10^{24}molecules\)
That was using Avogadro's number :)
Answer : The molecule of ethane present in 64.28 L of ethane gas at STP is, \(17.277\times 10^{23}\) molecule.
Solution :
At STP,
22.4 L volume of ethane present in 1 mole of ethane gas
64.28 L volume of ethane present in \(\frac{64.28L}{22.4L}\times 1mole=2.869moles\) of ethane gas
And, as we know that
1 mole of ethane molecule contains \(6.022\times 10^{23}\) molecules of ethane
2.869 moles of ethane molecule contains \(2.869\times 6.022\times 10^{23}=17.277\times 10^{23}\) molecules of ethane
Therefore, the molecule of ethane present in 64.28 L of ethane gas at STP is, \(17.277\times 10^{23}\) molecule.