Choose the correct answer for each question.

**When the pressure, temperature, and volume of a gas are known, the ideal gas law can be used to calculate**- molar amount
- Avagodro's number
- diffusion rates
- the distance from the Earth to the moon

**A sample of helium diffused 4.57 times faster than an unknown gas diffuses. What is the molar mass of the unknown gas? (atomic mass of He is 4.00)**- 12 g/mol
- 18.2 g/mol
- 38.8 g/mol
- 83.6 g/mol

**What is the volume occupied by 2.00 moles of hydrogen gas at 300 K and 1.25 atm?**- 39.4 L
- 5.60 L
- 14.9 L
- 3.81 L

**22.4 liters is the**- standard molar volume of a gas at STP
- molar volume of a gas, regardless of temperature and pressure
- the gas constant
- not applicable to gases at STP

**The coefficients in a balanced equation represent**- the volume ratio for gases only
- the volume ratio for all substances, regardless of what state (solid, liquid, gas)
- the mass ratio for gases only
- the mass ratio of all substances, regardless of what state (solid, liquid, gas)

**2HCl(g) yields H**_{2}(g) + Cl_{2}(g) in a decomposition reaction. How many grams of HCl must be used to produce 10 L of chlorine at STP? (mw of HCl is 36.5g/mol)- 32.6 g
- 15.8 g
- 30.2 g
- 36.5 g

**How many times faster will hydrogen gas diffuse thans nitrogen gas, at the same temperature and pressure? (mw of hydrogen is 1 g/mol; mw of nitrogen is 14 g/mol)**- 3.72 times faster
- 1.37 times faster
- 2.15 times faster
- 4.24 times faster

**If chlorine gas (mw 35.5 g/mol) and bromine gas (ms 80 g/mol) were injected into opposite ends of a long tube at the same time and allowed to diffuse toward the center, where would they meet?**- closer to the end that held the bromine gas
- closer to the end that held the chlorine gas
- exactly in the middle
- at 2:05 outside the school

**C(s) + 2H**_{2}(g) yields CH_{4}(g). How many volumes of hydrogen are needed to produce 20 liters of methane (CH_{4})?- 2.0
- 20
- 22.4
- 40

**A sample of helium effuses through a porous container 6.50 times faster than does unknown gas X. What is the molar mass of the unknown gas? (mw of helium 4 g/mol)**- 169 g/mol
- 56.0 g/mol
- 68.8 g/mol
- 118 g/mol

**What is the molar mass of a gas with a mass of 0.650 g occupying 1.12 L at 280 K and 1.14 atm?**- 11.7 g/mol
- 13.5 g/mol
- 39.8 g/mol
- 15.3 g/mol

**H**_{2}(g) + Cl_{2}(g) yields 2HCl(g) . In this reaction, what is the volume ratio of H_{2}(g) to HCl(g)?- 1 : 1
- 1 : 2
- 2 : 1
- 2 : 2

**What is the process in which gas molecules randomly mix and eventually reach the same concentration throughout their container?**- diffusion
- effusion
- confusion
- protrusion

**According to Avagadro's law, which of the following contain equal numbers of molecules?**- 1 L of H
_{2}(g) and 1 L of O_{2}(g) at the same temperature and pressure - 1 L of H
_{2}(g) and 1 L of O_{2}(g) regardless of thetemperature and pressure - 1 gram of H
_{2}(g) and 1 gram of O_{2}(g) at the same temperature and pressure - 1 L of H
_{2}(g) and 16 L of O_{2}(g) at the same temperature and pressure

- 1 L of H
**At a certain temperature and pressure, chlorine molecules have a velocity of 0.0380 m/s. What is the velocity of sulfur dioxide molecules under the same conditions?**- 0.0400 m/s
- 0.0380 m/s
- 0.4870 m/s
- 0.1860 m/s

**The density of a gas is 3.07 g/L at STP. Calculate the gas's molar mass.**- 68.8 g/mol
- 35.8 g/mol
- 83.9 /mol
- 1.26 g/mol

**Of volume, mass, and density, which are affected by changes in pressure and temperature?**- only volume
- only volume and density
- only volume and mass
- volume, mass, and density

**Which gas will diffuse faster, oxygen, carbon dioxide, or nitrogen?**- nitrogen
- carbon dioxide
- oxygen
- none--they will all diffuse at the same rate, since one mole of any gas has the same volume

**What is the mass of 2.25 mol of Cl**_{2}?- 160 g
- 170 g
- 35.45 g
- 71 g

**How many moles are contained in 5.60 L Cl**_{2}?- 0.250 mol
- 22.4 mol
- 5.56 mol
- 6.02 X 10
^{23}mol