chapter 5 gas notes.notebook - mrs. freeman's ap...

Chapter 5 gas notes.notebook

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November 10, 2016

Nov 61:02 PM

GasesChapter 5

Nov 61:17 PM

Gases Expand to fill their containers Fluid motion (they flow) Have low densities (1/1000 the density of equivalent liquids or solids)

Compressible Can Effuse and Diffuse

Effuse: The passage of a gas through a tiny hole into an evacuated (vacuumed) chamber

Diffusion: The mixing of gases (Spreading throughout a room)


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• Particles of matter are always in motionCollision of the particles with the walls is what causes pressure

• Particles are very small compared with the distance between them The volume of the individual particles can be assumed to be zero

• Particles exert no forces on each other The do not attract or repel each other (No IMFs)

• Average kinetic energy is proportional to temperature of a gasTemperature of a gas is measured in Kelvin

GasesKinetic Molecular Theory

Nov 61:23 PM

Ideal Gas: Imaginary gases that perfectly fit all of the assumptions of the kinetic molecular theory Tiny particles that are very spread apart relative to their size

Collisions between gas particles and between the particles and walls of the container are elastic collisions

No kinetic energy is lost in elastic collisions

There are no forces of attraction between the particles

Particles are in constant, rapid motion (therefore possess kinetic energy)

The average kinetic energy of particles depends on temperature, not the identity of the particles



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November 10, 2016

Nov 61:23 PM

GasesIdeal versus real gases Kinetic Molecular Theory

Tiny particles that are very spread apart relative to their size Low temperatures and high pressures

Collisions between gas particles and between the particles and walls of the container are elastic collisionsIMFs

There are no forces of attraction between the particlesIMFs

Nov 61:23 PM


Which of the following gases would be the least ideal? a. O2b. H2 c. Br2 d. Cl2

Under which of the following conditions of temperature and pressure would 1.0 mol of the real gas CO2(g) behave most like an ideal gas?

Temperature (K) Pressure (atm)a. 100 100b. 800 0.1c. 800 1d. 800 100


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November 10, 2016

Nov 61:40 PM

Pressure: The force created by the collisions of molecules with the walls of a container

Pascal (Pa): SI Unit of pressure. 1 Pa = 1 N/M2

Millimeter of Mercury (mm Hg): Pressure that supports a 1 mm column of mercury in a barometer

Atmosphere (atm): Average atmospheric pressure at sea level and 0℃

Torr (torr): 1 torr = 1 mm Hg

Gases

Nov 61:47 PM

1 Atm 101.3 kPa14.7 lbs/in2760 mm Hg760 torr

STP: Standard Temperature and Pressure

273 K

Standard Pressure Standard Temperature

Gases


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November 10, 2016

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Boyle's Law: Pressure is inversely proportional to volume when temperature is held constant

Gases

Nov 61:55 PM

Charles' Law: The volume of a gas is directly proportional to temperature (volume goes to zero when temperature is zero Kelvin)

Gases


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Gay Lussac's Law: The pressure and temperature of a gas are directly related, provided that the volume remains constant

Gases

Nov 61:55 PM

Combined Gas Law: Combines all of the gas laws in one equation keeping the amount of gas constant

Gases


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November 10, 2016

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Ideal Gas Law: Relates the amount of gas to the pressure, volume and temperature of the gas

PV = nRTP = pressure in atmV= volume in litersn = molesR = proportionality constant 0.0821 L*Atm/mol*K This can be different!!!

T= Temperature in Kelvins

Gases

Nov 62:06 PM

Avagadro's Law: For a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas (at low pressures)

V = (a)(n)a = proportionality constant

V = Volume of the gas

n = number of moles of gas

Gases


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Nov 62:12 PM

Gas Density

Molar volume at STP is 22.4L so at STP density is:

Gases

Nov 62:17 PM

How to Find Molar Mass of a Gas

D = MassVolume PV = nRT n = mass of gas

molar mass

Gases


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November 10, 2016

Nov 97:33 AM

PTotal = P1 + P2 + P3 + . . .

Dalton's Law of Partial Pressures: The total pressure of a mixture of gases is the addition of each pressure associated with each gas.

Mole Fraction: Xi = nintotal = Pi

Ptotal

Gases

Nov 97:33 AM

GasesA flask contains 0.25 mole of SO2(g), 0.50 mole of CH4(g), and 0.50 mole of O2(g). The total pressure of the gases in the flask is 800 mm Hg. What is the partial pressure of the SO2(g) in the flask?


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November 10, 2016

Nov 62:04 PM

If reactants and products are at the same temperature and pressure, then mole ratios of gases are also volume ratios

3 H2(g) + N2(g) à 2NH3(g)

3 moles H2 + 1 mole N2 à 2 moles NH3

3 liters H2 + 1 liter N2 à 2 liters NH3

GasesGas Stoichiometry

How many liters of ammonia can be produced when 12 liters of hydrogen react with an excess of nitrogen?

How many liters of oxygen gas, at STP, can be collected from the complete decomposition of 50.0 grams of potassium chlorate?

How many liters of oxygen gas, at 37.0C and 0.930 atmospheres, can be collected from the complete decomposition of 50.0 grams of potassium chlorate?

Nov 33:09 PM

GasesGas Stoichiometry A rigid 5.00 L cylinder contains 0.176 mol of NO(g) at 298 K. A 0.176 mol sample of O2(g) is added to the cylinder, when a reaction occurs to produce NO2.

a. Write the balanced equation for the reaction

b. Calculate the total pressure, in atm, in the cylinder at 298 K after the reaction is complete.


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November 10, 2016

Nov 97:33 AM

At the same conditions of temperature, all gases have the same average kinetic energy.

At the same temperature, small molecules move FASTER than large molecules

v = velocitym = mass

Gases

Nov 33:15 PM

The experimental apparatus represented above is used to demonstrate the rates at which gases diffuse. When the cotton balls are placed in the ends of a tube at the same time, the gases diffuse from each end and meet somewhere in between, where they react to form a white solid. Which of the following combinations will produce a solid closes to the center of the tube?

a. HCl and CH3NH2b. HCl and NH3c. HBr and CH3NH2d. HBr and NH3

Gases


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November 10, 2016

Nov 33:11 PM

GasesA rigid 5.00 L cylinder contains 24.5 g of N2(g) and 28.0 g of O2(g)a. Calculate the total pressure, in atm, of the gas mixture in the cylinder at

298 K.b. The temperature of the gas mixture in the cylinder is decreased to

280 K. Calculate each of the following.i. The mole fraction of N2(g) in the cylinder.ii. The partial pressure, in atm, of N2(g) in the cylinder.

c. If the cylinder develops a pinholesized leak and some of the gaseous mixture escapes, would the ratio of N2/O2 in the cylinder increase, decrease, or remain the same? Justify your answer.

Nov 145:50 PM

Same amount of gas molecules for each line

MaxwellBoltzmann Gas Distribution: Shows the average velocity of the gas sample due to the temperature of the gas

Gases


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November 10, 2016

Oct 293:23 PM

chapter 5 gas notes.notebook - mrs. freeman's ap...

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