SCH3UI - Unit 5: Gases

states of matter & KMT: solids

type of motion, attraction, & organization.

types of motion: vibrational

strength of attraction: strongest

organization of entities: highly organized

states of matter & KMT: liquids

type of motion, attraction, & organization.

type of motion: vibrational, translational, and rotational

strength of attraction: intermediate

organization of entities: intermediate level of organization

states of matter & KMT: gases

type of motion, attraction, & organization.

type of motion: vibrational, translational, and rotational

strength of attraction: weakest

organization of entities: least organized

kinetic molecular theory (KMT): what is it?

• the idea that all substances are composed of entities that are in constant, random motion

temperature: what is it?

in terms of kinetic energy

what happens to kinetic energy if the temperature increases?

• the measure of the average kinetic energy of the entities in a substance

• as temperature increases so does kinetic energy

why do scientists have defined 2 sets of standard conditions? (STP & SATP)

*from homework*

• defined STP to allow them to comare the results under identical conditions

• defined SATP because they more closely resemble conditions in a lab (+ more convinent as 0ºC is too fkn cold)

gas laws: Charles’ law

• temp of a gas increases, volume increases

• pressure & moles remain constant

(V₁/T₁) = (V₂/T₂)

gas laws: Boyle’s law

• pressure of a gas increases, volume decreases

• temp & moles remain constant

P₁V₁ = P₂V₂

gas laws: gay-lussac’s law

• pressure of a gas is directly proportional to its temperature. e.g. pressure increases, temperature increases

• volume & moles remain constant

(P₁/T₁) = (P₂/T₂)

gas laws: combined gas law

• relationship between V, T, & P

• moles remain constant

(P₁V₁/T₁) = (P₂V₂/T₂)

ideal gas law: PROPERTIES

1. high translational energy, moving randomly in all directions in straight lines

2. perfectly elastic collisions (no loss of kinetic energy)

3. volume of an ideal gas entity is insignificant (aka. 0) compared to the volume of the container

4. no attractive or repulsive forces between ideal gas entities

5. do not condense into liquids when cooled

no such thing

ideal gases are small molecules with very small intermolecular forces. e.g. H_2(g), He_(g), N_2(g)

ideal conditions: low pressure, high temperature

gas laws: ideal gas law (just the formula)

PV = nRT

p = pressure (kPa)

v = volume (L)

n = amount (mol)

r = universal gas constant: 8.314 (kpa x L)/(mol x k)

t = temperature (kelvins)

dalton’s law of partial pressures: determining total pressure

P_total = P₁ + P₂ + P₃ + …

*make this equation specifically designed to each given equation

dalton’s law of partial pressures: determining gas collected from water vapour and atmosphere

P_{gas collected} = P_atm - P_{water vapour}

*refer to formula sheet

avogadro’s law

• volume of a gas = amount of moles of a gas

• temp & pressure remain constant

V₁/n₁ = V₂/n₂

molar volume example bc idk how to explain

• volume that contains 1 mole of particles

• is the same for all gases at the same temperature & pressure

e.g. molar volume at STP

p = 101.325kpa

t = 273.15K

n = 1 mol

v = ?

using ideal gas law

→ the molar volume at STP is 22.4 L/mol

gas stoichiometry: finding volume if pressure & temp remain same and given volume

V_element = V_element x mole ratio

like how u would do for finding moles but for gases