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Chapter 5
Gases (Test 2)
Question | Answer |
---|---|
Which four variables are necessary to describe any gas? | pressure, volume, # of moles, and temperature |
What is the equation of pressure? | pressure = (force/area) |
What is the SI unit of force? | N (newton) |
What is the SI unit of area? | m^3 |
One atmosphere is equal to how many Torr? | 766 torr = 1 atm |
One Torr is equal to how many millimeters of mercury? | 1 mm Hg = 1 torr |
What does Boyle's Law state? | Under constant temperature conditions, P1V1 = P2V2. |
What does Charles's Law state? | Under constant pressure conditions, V1/T1 = V2/T2. |
What does Avogadro's Law state? | Under constant pressure and temperature conditions, V1/n1 = V2/n2. |
For gases that are measured at the same temperature and pressure, what do balanced chemical equations give us? | # mol |
The molar volume of a gas at STP is what? | 22.4 L |
What is STP (standard temperature and pressure)? | 273K and 1 atm |
What is the Ideal Gas Law? | PV=nRT |
What is the Combined Gas Law? | P1V1/n1T1 = P2V2/n2T2 |
What is the equation for molar mass, given density, temperature, and pressure? | Molar mass = dRT/P |
What is Dalton's Law of Partial Pressures? | Ptot = Pa + Pb + Pc + Pd + ... Pa = (Xa)(Ptot) where Xa = na/ntot |
What are first three postulates of the Kinetic Molecular Theory? | 1. Gases consist of individual particles in constant random motion. 2. The volume of gas particles is extremely small compared to the volume of the container. 3. Collisions between gas particles are elastic. |
What are the last two postulates of the Kinetic Molecular Theory? | 4. Attractions between gas particles are extremely weak and negligible. 5. The average kinetic energy of gas particles depends only on temperature and is directly proportional to temperature. |
What is the equation for kinetic energy? | KE = (1/2)(m)(V^(2)) |
diffusion | the spontaneous spreading of one substance through another |
effusion | when gas particles escape from a container through a tiny opening |
What is Graham's Law of Effusion? | r1/r2 = sqrt((m2/m1)) |
rate | distance/time |
ideal gas | a gas that obeys the Ideal Gas Law |
Most gases deviate from ideal behavior when? | at low temperature and high pressure |
Gases behave most ideally when? | at high temperature and low pressure |
The van der Waals equation does what? | attempts to correct the ideal gas law for real gases; it adjusts for pressure and volume. |