Question

The mass of a flask with a 1L volume that is evacuated to a pressure of 0.00 atm is found to be 92.01g. after introduction of an unknown ideal gas with a pressure of 3.00 atm and temprature of 27 Degrees C the mass of the flask and gas are found to be 97.37g. Identify the unknown gas.

Answer 1

CO₂

Step-by-step explanation:

We substract the mass of the empty flask from the mass of the flask + gas in order to calculate the mass of the gas:

• 97.37 g - 92.01 g = 5.36 g

The moles of this gas (n) can be expressed as:

• n = 5.36 g ÷ M

Where M is the molar mass.

We can calculate n using PV=nRT:

• P = 3.00 atm

• V = 1 L

• T = 27 °C ⇒ 27+273.16 = 300.16 K

3.00 atm * 1L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 300.16 K

• n = 0.122 mol

Now we can calculate the molar mass of the gas:

n = 5.36 g ÷ M

• 0.122mol = 5.36 g ÷ M

• M = 43.9 g/mol ≅ 44 g/mol

Thus, the gas is most likely CO₂.