A balloon contains 25.0 grams helium (He) gas at room temperature (22 °C) and occupies a volume of 75.0 L. How much pressure does the He gas exert on the walls of the balloon?

The pressure exerted by He on walls of balloon is 2.02 atm.

Explanation:

Given data:

Mass of helium = 25.0 g

Temperature = 22°C

Volume of gas = 75.0 L

Pressure exert by the gas on walls of balloon = ?

Solution:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the temperature.

22+273 = 295 K

Now we will calculate the number of moles of He.

Number of moles = mass/ molar mass

Number of moles = 25 g/ 4 g/mol

Number of moles = 6.25 mol

Now we will put the values in formula.

P × 75.0 L = 6.25 mol × 0.0821 atm.L/mol.K ×295 K

P × 75.0 L = 151.372 atm.L

P = 151.372 atm.L  / 75.0 L

P = 2.02 atm

The pressure exerted by He on walls of balloon is 2.02 atm.

1.solid

2.carbon dioxide

3.helium

there is none because earth is stationary and flat.