Important Equations chemistry

Question 1

enzyme velocity

Answer 1

V =

Vmax * [S])/(Km + [S]

Question 2

osmotic pressure

Answer 2

Π = iMRT

Question 3

Energy of electron - Bohr’s Model of the Hydrogen Atom

Answer 3

E = -Rh/n²

Question 4

Electromagnetic energy of photons - Bohr’s Model of the Hydrogen Atom

Answer 4

E = hc/λ

Question 5

Equilibrium constant for:

aA + bB ⇌ cC + dD

Answer 5

Kc = ([C]^c[D]^d)/([A]^a[B]^b)

Question 6

calorimetry heat equation

Answer 6

q = mc∆T

Question 7

Standard heat of reaction (∆H°rxn) - using heat of formations

Answer 7

∆H°rxn = (sum of ∆H°f of products) - (sum of ∆H°f of reactants)

Question 8

Standard heat of reaction (∆H°rxn) - using bond dissociation energies

Answer 8

∆H°rxn = ∑∆Hbonds broken - ∑∆Hbonds formed

Question 9

entropy

Answer 9

∆Suniverse = ∆Ssystem + ∆Ssurroundings

Question 10

Gibbs free energy (G) - thermodynamics

Answer 10

∆G = ∆H - T∆S

Question 11

Reaction Quotient for:

aA + bB ⇌ cC + dD

Answer 11

Q = ([C]^c x [D]^d)/([A]^a x [B]^b)

Question 12

Boyle’s Law

Answer 12

PV = k; P₁V₁ = P₂V₂

Question 13

Charles’s Law

Answer 13

V/T = k; V₁/T₁ = V₂/T₂

Question 14

Gay-Lussac’s Law

Answer 14

P/T = k; P₁/T₁ = P₂/T₂

Question 15

Avogadro’s Principle

Answer 15

n/V = k; n₁/V₁ = n₂/V₂

Question 16

Combined Gas Law

Answer 16

(P₁V₁)/T₁ = (P₂V₂)/T₂

Question 17

Ideal Gas Law

Answer 17

PV = nRT

Question 18

Van der Waals equation of state

Answer 18

Partial Pressures:

Pt = Pa + Pb + Pc ….

Question 19

root-mean-square speed

Answer 19

Urms = √(3RT/M)

Question 20

Freezing-Point depression

Answer 20

∆T = i x (Kf) x molality

Question 21

Boiling-Point elevation

Answer 21

∆T = i x (Kb) x molality

Question 22

diffusion formula

Answer 22

r₁/r₂ = (1/2) * [√(m₂/m₁)]

Question 23

percent composition by mass

Answer 23

(mass of solute/mass of solution) x 100%

Question 24

mole fraction

Answer 24

(number of moles of compound)/(total number of moles in system)

Question 25

molarity

Answer 25

(number of moles of solute)/(liter of solution)

Question 26

molality

Answer 26

(number of moles of solute)/(kilogram of solvent)

Question 27

normality

Answer 27

(number of gram equivalent weights of solute)/(liter of solution)

Question 28

pH equation

Answer 28

pH = -log[H⁺]

Question 29

pOH equation

Answer 29

pOH = -log[OH⁻]

Question 30

ionic product for water, Kw

Answer 30

Kw = [H⁺] x [OH⁻]

Question 31

Henderson-Hassebalch equation (buffer regions) - pH

Answer 31

pH = pKa + log([A-]/[HA])

Question 32

Henderson-Hassebalch equation (buffer regions) - pOH

Answer 32

pOH = pKb + log([conjugate acid]/[weak base])

Question 33

standard electromotive force (E°cell)

Answer 33

E°cell = E°cathode - E°anode

Question 34

Gibb’s free energy - electrochemistry

Answer 34

∆G = -nF(Ecell)