Unit 4 Quiz--Reactions with Gases--Thurston High Chemistry

Multiple Choice (Choose the best answer.)

Questions 1 - 3 use the fact that one mole of any gas occupies 22.4 L at standard temperature and pressure.

  1. 18 L of O2 would have a mass of how many grams?

    0.80 mol

    13 g

    26 g

    40 g

    13000 g

  2. 18 L of O2 would have have how many molecules?

    4.1 x 10 -27 molecules

    0.80 molecules

    4.8 x 10 23 molecules

    8.0 x 10 23 molecules

    2.4 x 10 26 molecules

  3. Use the molar mass and the molar volume of Ar gas to find its density (in g / L) at STP.

    0.56 g / L

    1.78 g / L

    22.4 g / L

    40. g / L

    9.0 x 10 1 g / L

    The rest of the quiz will require you to use mole highway relatioships:

  4. In the reaction CH4 (g) + O2 (g) CO2 (g) + H2O (g) 18 L of oxygen would produce how many L of CO2 at STP?(Hint: You must first balance the equation.)

    0.40 L

    9 L

    18 L

    36 L

    None of these

  5. In the reaction used in problem 4, 18 L of oxygen would produce how many g of H2O at STP? (Hint: You must use the balanced the equation.)

    7 g

    14 g

    22 g

    28 g

    None of these

  6. In the reaction used in problem 4, 18 g of oxygen would require how many L of CH4 at STP? (Hint: You must first balance the equation.)

    3.2 L

    13 L

    20. L

    880 L

    None of these.

    In the next few problems, the conditions are not at standard temperature and pressure. You might want to use the combined gas law to adjust conditions to STP so that you can use 22.4 L in one mole to help solve the problems.

  7. In the reaction, 3 H2 (g) + N2 (g) 2 NH3 (g), 25 L of N2 at 300 K and 2.0 atm would react to form how many moles of NH3? (Hint: First convert to the volume N2 to STP.)

    2.1 mol NH3

    4.1 mol NH3

    46 mol NH3

    91 mol NH3

    None of these.

  8. In the reaction shown in problem 7, 1.0 mole of H2 would produce how many liters of NH3 at 0 oC and 1.5 atm?

    130 L NH3

    45 L NH3

    15 L NH3

    10. L NH3

    None of these.

  9. In the reaction shown in problem 7, 4.0 grams of H2 would produce how many liters of NH3 at 0 oC and 1.5 atm?

    260 L NH3

    90. L NH3

    30. L NH3

    20.L NH3

    None of these.

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