Calculate the density of oxygen, O_2, under each of the following conditions: ST

Question

Calculate the density of oxygen, O_2, under each of the following conditions: STP 1.00 atm and 15.0 degree C Express your answers numerically in grams per liter. Enter the density at STP first and separate your answers by a comma. To identify a diatomic gas (X_2), a researcher earned out the following experiment: She weighed an empty 5.2-L bulb, then filled it with the gas at 1.60 atm and 26.0 degree C and weighed it again. The difference in mass was 9.5 g. Identify the gas. Express your answer as a chemical formula.

Explanation / Answer

Part A

PV= nRT

At STP: T = 273 K and P=1 atm
1*32/ 0.08206*273

32/22.40 = 1.43 g/l

Density at 1 atm and 15 deg C (288 K):

1*32/(0.08206*288)

32/23.63 = 1.35 g/l

1.43, 1.35

Part B

To identify a diatomic gas (X2) a researcher carried out the following experiment. She weighted an empty 5.2-L bulb then filled it with the gas at 1.60 atm and 26.0 degree Celsius and weighed it again. The difference in mass was 9.5g. Identify the gas

PV =nRT

n= PV/RT

26.0 degree Celsius = 299.15 Kelvin

n= PV/RT

n= 1.60*5.2/0.08206*299.15

n= 8.32/ 24.55

n= 0.3389

The difference in mass was 9.5g

9.5/0.3389

28.03 g/mol

But since it is a diatomic gas, that means you have to divide it by two to see the mass of each individual molecule.
28.03/2= 14.01

For the element with a mass of 14.01 it is Nitrogen.

Answer: Nitrogen (N2)

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