Chemistry Chapter 13-14(for test 2): Fundamental Equilibrium Concepts

Reversible reactions

Chemical reactions that can proceed in both the forward and backward directions under given conditions

Dynamic Equilibrium

The forward and reverse reactions occur at equal rates

Equilibrium constant (K)

Value of the reaction quotient for a system at equilibrium

Very large K value

A lot more products than reactants at equilibrium; forward reaction is favored

Very small K value

A lot more reactants than products at equilibrium; reverse reaction is favored

Reaction quotient (Q)

The reaction quotient is equal to the molarity of the products, multiplied together, over that of the reactants, multiplied together, with each molarity raised to the power of its coefficient in the balanced equation

Q less than K

The reaction proceeds forward; reactant concentration decreases and product concentration increases

Q greater than K

The reactions proceeds in reverse; reaction concentration increases and product concentration decreases

Heterogeneous Equilibrium

Solids (s) and liquids (l) are not included in the equilibrium constant expression, because the concentrations of them do not change during a reaction

1/K, or flip reactant and product concentrations

If you reverse a chemical equation, how does this effect K?

Raise K to the same factor

If you multiply the coefficients of a chemical reaction by a factor, how does this effect K?

Multiply the K values together

If you add two or more individual chemical equations together, how does this effect K?

Homogeneous Equilibrium

An equilibrium in which all the reactants are products are present in the same phase

Equation relating K_p with K_c

K_p=K_c(RT)^(Δn), where Δn = (c+d) - (a+b)

Le Chatelier’s Principle

When a chemical system at equilibrium is disturbed, it returns to equilibrium by correcting the disturbance

Exothermic

-ΔH

Endothermic

+ΔH

free energy change of a reaction under nonstandard conditions equation

ΔG_rxn=ΔG^o_rxn+RTln(Q)

Equation relating free energy change under standard conditions and K

ΔG^o_rxn=-RTln(K)

Arrhenius acid definition

A substance that will dissolve in water to produce H⁺ or hydronium (H₃O⁺)

Arrhenius base definition

A substance that will dissolve in water to produce hydroxide ions, OH^-

Bronsted-Lowry acid definition

A compound that donates a proton, H⁺

Bronstead-Lowry base definition

A compound that accepts a proton, H⁺

Conjugate base

What an acid becomes when it loses a proton

Conjugate acid

What a base becomes when it gains a proton

Conjugate acid-base pair

Two substances related to each other by the transfer of a proton

Amphoteric

A substance that can act as an acid or as a base

Autoionization

A reaction of H₂O molecules transferring protons yield hydronium (H₃O⁺) and hydroxide ions (OH^-)

value of Kw

K_w=1.0 × 10^-14

Basic pH

Concentration of OH^- is greater than concentration of H₃O⁺

Neutral pH

Concentrations of OH^- and H₃O⁺ are equal, at 1.0 × 10^-7

Acidic pH

Concentration of H₃O⁺ is greater than the concentration of OH^-

Equation for pH

p = -log[H₃O⁺]

Equation for pOH

pOH = -log[OH^-]

Strong acid

Hydrochloric acid (HCl)

Strong acid

Hydrobromic acid (HBr)

Strong acid

Hydroionic acid (HI)

Strong acid

Nitric acid (HNO₃)

Strong acid

Chloric acid (HClO₃)

Strong acid

Perchloric acid (HClO₄)

Strong acid

Sulfuric acid (H₂SO₄)

Strong acid concentration rule

Strong acids have the same H₃O⁺ concentration as the initial acid concentration

Strong base

LiOH

Strong base

NaOH

Strong base

KOH

Strong base

RbOH

Strong base

CsOH

Group 1A strong base concentration rule

Ratio of Group 1A base concentration to the produced OH concentration is 1:1

Strong base

Ca(OH)₂

Strong base

Sr(OH)₂

Strong base

Ba(OH)₂

Group 2A concentration rule

Ratio of Group 1A strong base concentrations to the produces OH concentration is 1:2

Weak acid

Hydrofloric acid (HF)

Weak acid

Acetic acid (CH₃OOH)

Weak acid

Formic acid (HCOOH)

Weak acid

Sulfurous acid (H₂SO₃)

Weak acid

Carbonic acid (H₂CO₃)

Weak acid

phosphoric acid (H₃PO₄)

Acid ionization constant (K_a)

The equilibrium constant for the ionization of a weak acid

weak base

CH₃NH₂

weak base

C₅H₅N

weak base

CO₃^2-

weak base

C₂H₅NH₂

weak base

C₆H₅NH₂

weak base

HCO₃^-

weak base

NH₃

Base ionization constant (K_b)

The equilibrium constant for the ionization of a weak base

Binary acids

Acids that contain hydrogen and another nonmental element

Binary acid strength

Increase from left to right and down a column

Oxyacids

Acidic compounds containing a nonmental and one or more hydroxyl groups

Oxyacids strength

Increases with the greater number of O and in terms of electronegativity