Gas & Equilibrium

Pressure

Force per unit area. (P)
- atmospheres (atm)
- 1 atm = pressure at sea level
physics: atm = 101.3 Kila Pascals KPa = 760mm Hg

Temperature

measure in Kelvin with gasses (T)
Celsius + 273 = K

Volume

How much space an object takes up (V)
- mL or L

Amount of gas

amount of gas (n) - moles
how many particles
1 mol = molar mass

Ideal Gas Law / constant

PV=nRT
PV/nT = R = 0.0821
units: atm(P) x L(V) / mol(n) x K(T)

Ideal Gas

an imaginary gas whose particles are infinitely small and do not interact with each other (no IMF’s)

La Chatelier's Principle

Equilibrium will adjust its ratio to counter stresses and maintain equilibrium, shifting left or right minimizing effect

Temp impact on equilibrium

Heat is the same as a chemical = shift right or left, changes K and Q catches up

exothermic reactions

heat is a product, being released, delta H (system looses energy)

endothermic reactions

heat is a reactant, being used, delta H (system gains energy)

Pressure impact on equilibrium

- dec vol, inc pressure, get rid of gas
- inc vol, dec pressure, more gas
only if changing vol

Catalyst

no effect on equilibrium- just speeds up reaction by lowering activation energy needed to reach activated complex

study of chemical Kinetics

how long a reaction takes

collision theory

states that atoms, ions, and molecules must collide in order to react
- if collision is not w/ enough energy or right orientation, the reaction wont happen

Reaction rate

how likely atoms are to react
- to inc use collision theory: inc reactans, inc temp, inc surface area (break pieces up)

energy diagram

Visual representation of energy changes in a reaction

activation energy

Energy needed to get a reaction started -> activated complex (vertex)

STP

standard temperature and pressure: 1 atm, 0C, 273K

enthaply

change in energy (delta H)

units for measuring rate of reaction

molarity per unit of time

brackets around a chemical mean….

the molarity of that chemical

Reaction quotient

Q - changes when concentrations r changed

K - changes when temp is changed

Equilibrium

A state at which the reactions products and reactants are constant

Equilibrium constant

the ratio of products to reactants at equilibrium