Dalton's law of partial pressures

Answer Key - Grade 10 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   A tank's gas mix has partial pressures of 0.6 atm (N₂), 0.3 atm (O₂) and 0.1 atm (other gases). What is the total pressure, Ari?

   1 atm
2. 2.

   A bike tire's air has partial pressures of 2.34 atm (N₂), 0.628 atm (O₂) and 0.032 atm (other gases). What is the total pressure, Bo?

   3 atm
3. 3.

   A balloon's gas has partial pressures of 0.39 atm (N₂), 0.105 atm (O₂) and 0.005 atm (other gases). What is the total pressure, Kira?

   0.5 atm
4. 4.

   A balloon holds N₂ at 0.78 atm and O₂ at 0.21 atm, plus 0.01 atm of other gases. What is the total pressure, Jun?

   • 0.99 atm, leaving out the other gases
   • 1.00 atm, the sum of the parts
   • 0.78 atm, the largest part alone
5. 5.

   What does Dalton's law say about a mix of gases, Luz?

   • The heaviest gas sets the total pressure
   • The total pressure is the pressure of the main gas alone
   • The total pressure is the sum of each gas's pressure
6. 6.

   About what share of dry air is oxygen, by NOAA's figures, Pia?

   • About 21%
   • About 1%
   • About 78%
7. 7.

   Which gas is the third most common in dry air, at 0.934%, Ren?

   • Argon
   • Carbon dioxide
   • Oxygen
8. 8.

   A tank has 1 mol of O₂ and 3 mol of N₂. What is O₂'s mole fraction, Tala?

   • 0.75, the N₂ share
   • 0.33, from 1 ÷ 3
   • 0.25, from 1 ÷ 4
9. 9.

   O₂'s mole fraction is 0.25 and the total pressure is 2.0 atm. What is O₂'s partial pressure, Zee?

   • 2.0 atm, the whole total
   • 0.5 atm
   • 1.5 atm, the N₂ share
10. 10.

    Why is a gas's share of the pressure equal to its share of the moles, Esme?

    • Heavier particles add more pressure
    • Each particle adds to the pressure the same way
    • The main gas alone adds pressure