Stoichiometry

Stoichiometry in gases

1. Why do scuba divers need to exhale air when they ascend to the surface of the water?

2. At constant temperature, increasing the gas pressure will cause a _______________in its volume.

3. Equal volumes of gaseous CO2 and CH4 at the same temperature and pressure, contain the same number of moles. True__________ False __________

4. Equal volumes of gaseous CO2 and CH4 at the same temperature and pressure, contain the same number of grams. True__________ False _________

5. The volume occupied by a gas depends on its temperature, pressure and

6. If the temperature of a gas sample increases from 25ºC to 50ºC , its volume __________ at constant pressure.

7. One mol of Cl2 at 20 ºC and 1 atm occupies a volume of: _______________liters.

8. STP conditions are:

9. A balloon is filled with helium gas. When the following changes are made , which of these diagrams (A, B or C) shows the new volume of the balloon?

a. The balloon floats to a higher altitude where the outside pressure is lower._________

b. The balloon is taken inside the freezer, there have the same pressure different temperature_____

c. The balloon is filled with the same number of moles and the same conditions of temperature and pressure, but we used Hydrogen instead of Helium _______

Initial volume A B C

10. According to the following reaction: 2HCl + Zn ---------- H2(g) + ZnCl2 (aq)

a) Find the moles of hydrogen that can be produced with 6.54 moles of zinc.

b) Find the volume for the hydrogen produced in the last problem if the reaction occurs at a temperature of 300 K and a pressure of 202 kPa.

12. According to the following reaction:

2Na (s) + Cl2 (g) -----→ 2NaCl (s)

a)How many moles of Chlorine are needed to produce 100 moles NaCl?

b)What´s the volume occupied by the moles, obtained in part a, at 315°K and 101 kPa?

13. According to the following reaction:

2KClO3 ---→ 2KCl + 3O2

a) What volume of Oxygen would be produced at STP from

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