gases

ideal gas

law of combining volumes

gases combine at constant temperature and pressure, volumes are in ratio of simple whole numbers

avogadro’s law

• v is directly proportional to n

• equal volume of gas contain same number of molecules

• V₁/n₁ = V₂/n₂

• pressure and temperature is constant

• more gas molecules = more space needed to move

molar volume

all gases have a certain volume that contains exactly 1 mole of particles

law of combining volumes formula

V₁/n₁ = V₂/n₂

combined gas law formula

P₁V₁T₂ = P₂V₂T₁

combined gas law

• PV is directly proportional to T

• number of gas moles is constant

formula of charles law

V₁/T₁ = V₂/T₂

charles law

• V is directly proportional to T

• when temperature increase - volume increase

• when temperature decrease - volume decrease

• moles of gas and pressure is constant

charles law explanation

temperature and volume are directly proportional

• increasing temperature increases kinetic energy of gas molecules (directly proportional)

• hence, speed of molecules increases causing an increase in collision frequency

• To mantain the same pressure, the volume must increase to create more space for molecules to move

volume of gas increase

• particles need to speed up to maintain pressure

• travel far and colliding with same frequency

• increase velocity

volume of all gasses

• extrapolate to zero at the same temperature

• -273.15 °C

P₁V₁ = k

initial measure of pressure and volume

P₂V₂ = k

final measure of pressure and volume after a change

Boyle’s law

• inversely proportional

• p is directly proportional to 1/v

• pressure decreased - volume increase

• pressure increased - volume decreased

• number of moles and temperature is constant

Boyle’s law explanation

volume and pressure are inversely proportional

• decreasing volume decreases the amount of space for gas molecules to move

• hence increasing the collision frequency

• therefore increasing the pressure

IMFs become stronger with more compacted gas particles - deviates from an ideal gas

formula for boyle’s law

P₁V₁ = P₂V₂

factors that affect gasses

• pressure - kPa

• volume - L

• temperature - K

• amount of moles - mol

Ideal gas law

• inversely and directly proportional

• all formulas derived from it

ideal gas

• small molecules

• kinetic energy proportional to absolute temperature

• increased volume

• negligable volume and IMFs due to large space between them

• temperature ↑ and pressure ↓

molar mass

grams/moles

ideal gas law formula (moles given)

PV = nRT

• P - pressure

• V - volume

• n - number of moles

• R - Ideal Gas Constant

• T - temperature

ideal gas law formula (mass given)

PV = mRT/M

• P - pressure

• V - volume

• m - mass

• M - molar mass

• R - Ideal Gas Constant

• T - temperature

ideal gas constant

8.314 kpa x L / K x mol

Density

• ratio of chemical’s mass to volume it occupies

• p = m/V

• proportional to mass, moles, pressure, molar mass

sig digs for adding and subtracting

least number of decimals

sig digs for multiplying and dividing

count sig digs

solids

• Definite shape

• Definite volume

• Particles vibrate around fixed axes

• particles in contact, fixed

• no thermal energy to overcome interactions

liquids

• No definite shape (takes the shape of its container)

• definite volume

• Particles are free to move over each other but still attracted to each other

• particles in contact, not fixed

• enough energy to partially overcome intermolecular interactions

gases

• No definite shape (takes the shape of its container)

• No definite volume

• Particles move in random motion (little/no attraction to each other)

• particles not in contact/random

• enough energy to completetly overcome intermolecular interactions

physical properties of gas

• highly compressible

• fill container

• diffuse in any available space

• affected by temperature

monoatomic

consists of one atom

diatomic

• consists of two atoms

• HOFINBrCl

KMT

smallest entities of a substance are

• in continuous motion

• colliding with each other/objects in their path

5 big assumptions

• constant random motion

• negligible volume

• exerts no force on each other

• collide elastically with each other/container walls

• kinetic energy directly proportional to absolute temperature of gas

constant random motion

• gas is composed of a large number of particles

• higher energy than liquids or solids

negligible volume

• distance between gas molecules is greater than the size of the molecules

• easy to compress a gas - decrease distance

exerts no force on each other

• Intermolecular interactions are weak - negligible

• No attractions or repulsions

• Treats all gases as a collection of particles that are identical in all respects except mass

Collide elastically

• collision with each other and container walls are elastic

• do not change the average kinetic energy of the molecules

Kinetic energy proportional to absolute temperature of gas

• average kinetic energy depends on only the temperature

• all gasous molecules have same average kinetic energy

pressure - ideal and real

• ideal gas - low pressure

• real gas - high pressure

temperature - ideal and real

• ideal gas - high temperature

• real gas - low temperature

ideal gas graph

• more pressure - deviates from an ideal gas

• lower temperature - deviates from an ideal gas

ideal gas vs real gasses

• temperature ↑ and pressure ↓

• Small molecules behave more ideally than large gas molecules

• strong IMFs = less like an ideal gas

ideal gas

• no attractive/repulsive force between particles

• no volume

• collisions are elastic (no loss of kinetic energy)

real gas

• small attractive forces between particles

• small volume

• collisions are not elastic (lose energy)

real and ideal gasses similarities

• made of small particles that have mass

• gases are mostly empty space

• low density

converting temperature

• measure of kinetic energy

• higher temperature = greater kinetic energy

• Fahrenheit

• Celsius

• Kelvin

STP

standard temperature and pressure

SATP

standard ambient temperature and pressure

celcius to kelvin

K  =  ºC + 273.15

pressure

• concentration of force (per unit area)

• p = f/a

atmospheric pressure

Earth’s surface experiencing a net pressure

atmospheric pressure decreases

• volume increases

• temperature decreases

converting units of pressure

• atmospheres (atm)

• millimetres of mercury (mmHg)

• kilopascals (kPa)

ATM conversions

• 1 atm =  760 mmHg

• 1 atm =  101.325 kPa

mmHg conversions

• 760 mmHg =  1 atm

• 760 mmHg =  101.325 kPa

kPa conversions

• 101.325 kPa =  1 atm

• 101.325 kPa =  760 mmHg

gay-lussac’s law

• P₁/T₁ = P₂/T₂

• p is directly proportional to t

• number of moles and volume is constant

gay-lussac’s law explanation

pressure and temperature are directly proportional

• as temperature increases, the kinetic energy increases (directly proportional to temperature) (KMT)

• hence, the collision frequency increases, resulting in an increase in pressure

limiting reactant

• the reactant that is completely consumed

• limits the amount of product formed

• when it stops, the chemical reaction stops

excess reactant

substance left over after the reaction occured

graphing

• title: y vs x

• right side of table - y

• left side of table - x

• dependent/responding - y

• independent/manipulated - x

• upwards - y

• horizontal - x