Dalton's law of partial pressures

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Dry air at 101.325 kPa is 20.946% oxygen (NOAA). What is the partial pressure of oxygen, to 0.01 kPa, Bo?

   21.22 kPa
2. 2.

   Dry air at 101.325 kPa is 78.084% nitrogen (NOAA). What is the partial pressure of nitrogen, to 0.01 kPa, Esme?

   79.12 kPa
3. 3.

   A car tire on a hot day holds air at 350 kPa (absolute). About what is the partial pressure of N₂, at 78.084%, Luz?

   • About 78.1 kPa
   • About 273.3 kPa
   • About 73.3 kPa, the O₂ share
4. 4.

   At 101.325 kPa, about what is the partial pressure of argon in dry air (0.934%), Milo?

   • About 0.93 kPa
   • About 0.95 kPa
   • About 94.6 kPa, without dividing by 100
5. 5.

   Humid air can be up to about 4% water vapor (NOAA). At 101.325 kPa, about what is that water vapor's partial pressure, Noah?

   • About 4.05 kPa
   • About 40.5 kPa
   • About 97.3 kPa, the other gases' share
6. 6.

   When humid air holds 4% water vapor, NOAA puts nitrogen at about 74.96%. Why is that below 78.084%, Pia?

   • Humid air holds more nitrogen, not less
   • Water vapor turns some nitrogen into oxygen
   • The water vapor takes part of the total, so the other shares shrink
7. 7.

   N₂ 79.12 kPa, O₂ 21.22 kPa, argon 0.95 kPa and CO₂ 0.04 kPa. What total do they give, Ren?

   • About 101.33 kPa, close to 1 atm
   • About 100.34 kPa, leaving out argon and CO₂
   • About 79.12 kPa, the N₂ alone
8. 8.

   Two tanks of the same volume and temperature each hold 2 mol of gas: one O₂, one CO₂. How do their pressures compare, Tala?

   • The O₂ tank's is higher, since O₂ moves faster
   • The CO₂ tank's is higher, since CO₂ is heavier
   • They are equal: same moles, volume and temperature
9. 9.

   Adding 1 mol of argon to a sealed box of 1 mol of N₂ at the same temperature does what to the total pressure, Zee?

   • Nothing, since argon is a noble gas
   • It doubles, since the moles double
   • It rises more than double, since argon is heavier
10. 10.

    In a gas mix, which gas has the largest partial pressure, Ari?

    • The gas listed first on the label
    • The gas with the most moles
    • The gas with the heaviest particles