Chemistry Chapter 11: Gases

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Questions and Answers

Match the gas law with its corresponding mathematical expression:

Boyle's Law = $p_i V_i = p_f V_f$ Charles's Law = $V = kT$ Gay-Lussac's Law = $P_i/T_i = P_f/T_f$ Avogadro's Law = $V/n = k$

Match the gas law with its main focus:

Ideal Gas Law = Relation between pressure, volume, temperature, and moles Combined Gas Law = Relating initial and final states of a gas Gay-Lussac's Law = Pressure and temperature relation Avogadro's Law = Volume and number of moles relation

Match the value of R with its corresponding units:

0.0821 = $L ext{ } atm/(mol ext{ } K)$ 8.314 = $J/(mol ext{ } K)$ R = Gas constant

Match the gas law with its description:

Ideal Gas Law = Describes the relationship between pressure, volume, temperature, and amount of gas Boyle's Law = Pressure of a gas varies inversely with its volume at constant temperature Charles's Law = Volume of a gas is directly proportional to its temperature at constant pressure Avogadro's Law = Volume of a gas is directly proportional to the number of moles at constant temperature and pressure Signup and view all the answers

Match the description with the correct gas law:

States that pressure is constant = Charles's Law Describes the inverse relationship between pressure and volume = Boyle's Law States that volume is constant = Gay-Lussac's Law Relates volume to the number of moles = Avogadro's Law Signup and view all the answers

Match the gas law with its mathematical expression:

Ideal Gas Law = PV = nRT Combined Gas Law = P1V1/T1 = P2V2/T2 Gay-Lussac's Law = P1/T1 = P2/T2 Charles's Law = V1/T1 = V2/T2 Signup and view all the answers

Match the statement to the corresponding gas law:

If temperature increases, volume increases = Charles's Law At constant temperature, pressure and volume are inversely proportional = Boyle's Law Pressure increases with temperature at constant volume = Gay-Lussac's Law Volume is directly proportional to moles = Avogadro's Law Signup and view all the answers

Match each law with its applicable condition:

Ideal Gas Law = Relates to all variables of a gas under ideal conditions Avogadro's Law = Applies at constant pressure and temperature Gay-Lussac's Law = Describes behavior at constant volume Combined Gas Law = Combines Boyle's and Charles's laws under changing conditions Signup and view all the answers

Match the variable with its definition in the context of gas laws:

P = Pressure exerted by the gas V = Volume occupied by the gas T = Temperature of the gas in Kelvin n = Number of moles of the gas present Signup and view all the answers

Match the gas law with its historical scientist:

Boyle's Law = Robert Boyle Charles's Law = Jacques Charles Avogadro's Law = Amedeo Avogadro Gay-Lussac's Law = Joseph Louis Gay-Lussac Signup and view all the answers

Match the following gas law terms with their formulas:

Ideal Gas Law = PV = nRT Combined Gas Law = P1V1/T1 = P2V2/T2 Dalton's Law = Ptotal = PA + PB Avogadro's Law = V/n = k Signup and view all the answers

Match each gas behavior with the appropriate condition:

Amonton's Law = Constant volume Avogadro's Law = Constant temperature and pressure Gay-Lussac's Law = Constant volume Dalton's Law = Mixture of gases Signup and view all the answers

Match the law to its key concept:

Dalton's Law = Partial pressures of gases in a mixture Ideal Gas Law = Relationship between pressure, volume, temperature, and moles Amonton's Law = Behavior of gases under temperature change Gay-Lussac's Law = Pressure changes with temperature at constant volume Signup and view all the answers

Match the gas property with its corresponding behavior:

Increased temperature = Increased pressure at constant volume Equal moles of gas = Equal volumes at the same temperature and pressure Increased volume = Decreased pressure at constant temperature Quantity of gas = Directly affects volume under constant temperature and pressure Signup and view all the answers

Match the gas laws with their areas of application:

Ideal Gas Law = Engines and refrigerators Dalton's Law = Gas mixtures and partial pressures Avogadro's Law = Determining gas volumes from moles Gay-Lussac's Law = Temperature change effects in sealed containers Signup and view all the answers

Match the law to the correct constant relationship:

Combined Gas Law = P1V1/T1 = P2V2/T2 Avogadro's Law = n1/V1 = n2/V2 Gay-Lussac's Law = P1/T1 = P2/T2 Amonton's Law = P/T = constant Signup and view all the answers

Match the terms with the corresponding gas law context:

Molecular View = Analyzing gas behavior under different conditions Pressure and Temperature = Amonton's Law aspect Partial Pressure = Dalton's Law focus Directly Proportional = Key concept in Gay-Lussac's Law Signup and view all the answers

Study Notes

Chapter 11: Gases

Gases are one of three main states of matter
Gases have unique properties in terms of volume, temperature, and pressure
These properties are explained by Kinetic Molecular Theory (KMT), which examines the properties of gases at a molecular level
KMT postulates that gas particles are constantly moving, colliding and exerting forces
Substances can exist as a solid, liquid, or gas depending on pressure and temperature conditions
Gases take up much more volume than liquids or solids due to their particles being far apart from each other
Gases flow very freely and have low densities
Gases mix homogeneously in any proportion, meaning they appear to dissolve into one another evenly
Pressure is force per unit area exerted by gas particles
A barometer is used to measure atmospheric pressure
The SI unit for pressure is the Pascal (Pa)
Common units for pressure include mm Hg (torr), atm, and kPa
Standard Temperature and Pressure (STP) is a set of standard conditions for comparing gases: 0°C (or 273.15 K) and 1 atm (or 760 torr)
At STP, 1 mole of an ideal gas occupies 22.4 L
Ideal Gas Law (pV = nRT) describes relationships between pressure (P), volume (V), amount of gas (n), ideal gas constant (R), and temperature (T)

Skills Needed

Knowledge of stoichiometric relationships in chemical reactions
Understanding of intensive properties (per mole)
Familiarity with physical states (both atomic and macroscopic)
Understanding of forces and temperature units, and conversions

Gases vs. Liquids and Solids

Gas volume changes significantly with pressure and temperature
Gases flow freely
Gases have relatively low densities
Gases can form homogenous solutions in any proportion

Kinetic-Molecular Theory (KMT)

Explains gas behavior at a molecular level, rather than a macroscopic level
Gas particles exert pressure by colliding with the walls of their container
Gas particles under pressure are frequently colliding with container walls
Gases are compressible due to the large spaces between particles
Gases contribute to the total pressure proportionally to their number of particles
Increasing temperature increases the average kinetic energy of gas particles
The mass of the gas particles has no effect on their pressure at a constant temperature
Heavier gases are not necessarily more pressurized than lighter gases at the same temperature, as it is the amount (moles) of the gas and its temperature that determine pressure

Postulates (Main Ideas) of KMT

Gas particle volume is negligible in comparison to the total volume
Gas particles are in constant, random, straight line motion until they collide with each other or the container walls
Gas particle collisions are elastic, meaning kinetic energy is conserved

Kinetic Energy and Gas Behavior

Kinetic energy is energy associated with motion
Temperature measures the average kinetic energy of particles in a gas
Heavier molecules have slower speeds than lighter ones at the same temperature

Pressure

Gravity attracts atmospheric gases, causing a uniform force (pressure) on everything
Pressure = force/area
Barometer measures atmospheric pressure in units of mm Hg
Sea level atmospheric pressure is 760 mm Hg = 1 atm

Units of Pressure

SI unit for force is the Newton (N)
SI unit for pressure is the Pascal (Pa)
Standard atmospheric pressure is 101,325 Pa
1 atm = 101,325 Pa = 101.325 kPa
1 mm Hg = 1 torr
760 mm Hg = 760 torr = 1 atm

Standard Conditions (STP)

STP = 0°C (or 273.15 K) and 1 atm (or 760 torr)
One mole of an ideal gas occupies 22.4 L at STP

The Gas Laws

Gas behavior is described using pressure (P), volume (V), temperature (T), and amount of gas (n)
These variables are interrelated, so one can be determined from measuring the other three

Ideal Gas Law

pV = nRT
R is the ideal gas constant, which has different values for different units
Ideal gas laws can be determined from the combined gas law

Remaining Gas Laws

Boyle's Law (pressure-volume relationship, constant temperature and amount)
Charles's Law (temperature-volume relationship, constant pressure and amount)
Gay-Lussac's Law (pressure-temperature relationship, constant volume and amount)
Avogadro's Law (amount-volume relationship, constant pressure and temperature)
Combined Gas Law

The Gas Laws - Summary Table

The table summarizes various gas laws and their relationships between gas variables

Types of Gas Law Problems

Type 1: Change in one variable causes a change in others, while the remaining variables remain constant
Type 2: One variable is unknown, but the other three are known, and no change occurs

Practice with Gas Laws

Worked examples using ideal gas equation and gas laws to solve problems related to pressure, temperature and volume calculations for specific gas conditions (O2, methane)

Density, Molar Mass, Partial Pressures

Ideal Gas law rearranged to find gas density, molar mass, partial pressure of each gas in a gas mixture

Partial Pressures

Ideal Gas Law applies to a gaseous mixture
Dalton's Law of Partial Pressures: each gas in a mixture exerts a partial pressure, and the total pressure is the sum of the partial pressures
Mole fraction (XA) = moles of component A / total moles
Partial pressure (PA) = mole fraction of A x total pressure

Dalton's Law of Partial Pressures (Examples)

Worked examples calculating mol fraction and partial pressures for specific gasses in a mixture

Summary

Key points and concepts for understanding gases (KMT, gas laws) and being able to use them for calculations involving stoichiometry, density, molar mass, and partial pressures of gasses.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating properties of gases as one of the main states of matter in this quiz on Chapter 11. Discover how Kinetic Molecular Theory explains gas behavior, including volume, temperature, and pressure. Test your understanding of critical concepts like atmospheric pressure and the units used to measure it.