i do not know how to work this out please help me
How many oxygen molecules are present in 113.97 liters of oxygen gas at STP?
Use dimensional analysis,
113.97 liters (1 mol of O2/22.4 liters) (6.02*10^23 molecules/1 mol of O2)
Can you finish it?
At STP, the molar volume of an ideal gas is 22.4 L. In other words, the volume of 1 mol of a gas like oxygen is 22.4 L. (mol/22.4L) or (22.4L/mol)
The problem gives you 113.97 L of oxygen. Using dimensional analysis, you can find the number of moles of oxygen.
113.97 L x (1 mol/22.4L) = 5.0879 mol of oxygen.
The problem asks for the number of oxygen molecules and the number of molecules in a mol is 6.02 x 10^23.
5.0879 mol oxygen x ((6.02 x 10^23) oxygen molecules/ mol oxygen ) = 3.06 x 10^24 molecules
First let's figure how many moles of oxygen are present.
At STP, 1 mole occupies 22.4 liters. So,
113.97 liters * (1 mole / 22.4 liters) = 5.09 mole.
Now there are 6.02e23 molecules per mole. So multiplying this by the number of moles, we get
(6.02 x 1023 molecules / mole)(5.09 mole) = 3.06 x 1024 molecules.
Hope this helps.