If you filled up three balloons with equal volumes of hydrogen, argon, and carbon dioxide gas all at the same temperature and pressure, which balloon would weigh the most? which balloon would weigh the least?
Just suppose the balloons had a volume of 22.4L. At STP 1 mol of gas occupies 22.4L; therefore, you would have 1 mol H2, 1 mol Ar, and 1 mol CO2. How much is a mole of each?
To determine which balloon would weigh the most and which would weigh the least, we need to consider the molar masses of hydrogen (H2), argon (Ar), and carbon dioxide (CO2). The molar mass is the mass of one mole of a substance, and it is expressed in grams.
First, let's determine the molar masses of the gases:
- Hydrogen (H2): The molar mass of hydrogen is 2 grams/mole (2 g/mol) since hydrogen gas consists of two hydrogen atoms (each with an atomic mass of 1 gram/mole).
- Argon (Ar): The atomic mass of argon is 39.95 grams/mole (39.95 g/mol).
- Carbon Dioxide (CO2): The molar mass of carbon dioxide is calculated by adding the atomic masses of one carbon atom (12.01 grams/mole) and two oxygen atoms (16.00 grams/mole each). So, the molar mass of carbon dioxide is 12.01 + 16.00 + 16.00 = 44.01 grams/mole (44.01 g/mol).
Now, let's compare the molar masses:
- Hydrogen (H2): 2 g/mol
- Argon (Ar): 39.95 g/mol
- Carbon Dioxide (CO2): 44.01 g/mol
Based on their molar masses, the balloon filled with argon (Ar) would weigh the most since it has the highest molar mass. The balloon filled with hydrogen (H2) would weigh the least since it has the lowest molar mass.
Therefore, the balloon with argon gas would weigh the most, and the balloon with hydrogen gas would weigh the least.