Chemistry 117 Exam 2

Forward reaction

Reaction that goes left → right (reactants → products)

Reverse reaction

Reaction that goes right → left (products → reactants)

Reversible reaction

Reaction that goes both directions; at equlibrium, both are occuring at the same rate

Exothermic reaction

Heat leaves the system as a product; shift left

Endothermic reaction

Heat enters the system as a reactant; shift right

Color shift

Heat causes color shift; color displays the way it shifted

High K_a

Indicates a strong acid; high dissociation; high in H⁺; low in pH

Low K_a

Indicates a weak acid; low dissociation; little in H⁺; high in pH

-log[H⁺] or 14-pOH

Calculating pH

-log[OH^-] or 14-pH

Calculating pOH

10^-pH

Calculating [H⁺]

[H⁺]²/([HA]-[H⁺]) or K_w/K_b

Calculating K_a

[H+][OH-]=1E-14

Calculating K_w

Produces H₃O⁺

Cation equation (acid)

Produces OH^-

Anion equation (base)

Buffer solution

Resists changes in pH when small amounts of acid or base are added; contains a weak acid/base and its conjugate acid/base that removes/neutralizes it

Natural buffers

Buffers that occur naturally, producing reactions without changing pH; examples are human blood, tomato juice, ocean, etc.

pH=pKa​+log(base/acid)

Henderson–Hasselbalch Equation

H⁺

Acids will have more ____ than its conjugate base

Acid donates H⁺, base accepts H⁺

Brønsted–Lowry Definition

14 - (-log[H⁺])

When given a strong acid and you want to find pOH…

High solubility

High K_sp indicates…

Low solubility

Low K_sp indicates…

Factors affecting solubility

Interactive forces (solute-solute, solute-solvent, solvent-solvent), temperature, and pressure (gas)

Molar solubility * molar mass

Solubility in g/L

(s)(2s)²

Calculating K_sp

C_calΔT

Calculation of heat of reaction (qrxn) given Ccal; positive when endothermic, negative when exothermic

qrxn (in kJ) /moles of reactant (or water)

Calculation of Enthalpy of neutralization