Question

1. To identify a diatomic gas (X2 ), a researcher carried out the following experiment: She weighed an empty 4.8-L bulb, then filled it with the gas at 1.60 atm and 29.0 ∘C and weighed it again. The difference in mass was 8.7 g . Identify the gas.

2.Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose that a can contains a residual amount of gas at a pressure of 745 mmHg and a temperature of 35 ∘C . What would the pressure be if the can were heated to 1290 ∘C ?

Answer 1

1. To identify a diatomic gas (X2 ), a researcher carried out the following experiment: She weighed an empty 4.8-L bulb, then filled it with the gas at 1.60 atm and 29.0 ∘C and weighed it again. The difference in mass was 8.7 g . Identify the gas.

Solution :- P =1.60 atm , T= 29.0 C +273 = 302 K , V= 4.8 L

Lets first calculate the moles of gas using the ideal gas law

PV= nRT

PV/RT= n

1.60 atm * 4.8 L / 0.08206 L atm per mol K * 302 K = n

0.3099 mol = n

Now lets calculate the molar mass of the gas

Molar mass = mass / moles

                    = 8.7 g / 0.3099 mol

                    = 28.07 g/ mol

So the N2 gas have the same molar mass therefore the diatomic gas will be N2

2.Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose that a can contains a residual amount of gas at a pressure of 745 mmHg and a temperature of 35 ∘C . What would the pressure be if the can were heated to 1290 ∘C ?

Solution :- P1 = 745 torr , T1 = 35 C +273 = 308 K

P2 = ? , T2 = 1290 C +273 = 1563 K

P1/T1 = P2/T2

P2 = P1*T2/T1

P2 = 745 torr * 1563 K / 308 K

P2 = 3781 torr

So the pressure after heating the can will be 3781 torr.