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Calculate the mass of the following gas sample at STP. 151 mL O2

User Ilya Sabanin
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1 Answer

27 votes
27 votes

We are required to calculate the mass of the gas at STP, we are given its volume.

Remember at STP:

1 mole = 22.4 L

volume = n x 22.4 L

We can use the above equation to first find the number of moles, then after we can find the mass. Covert the volume to litres.

V= n x 22.4 L

0.151 L = n x 22.4

n = 6.741x10^-3 mol

Now we have the number of moles and molar mass of O2 = 15.999 g/mol

m = 6.741x10^-3 mol x 15.999 g/mol

m = 0.108 g

User Guillermina
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