chemistry: chapter 9

9.1-9.3 learning objectives

arrhenius acid

compounds that produce H3O+ in solution when they dissociate

arrhenius base

compounds that produce OH- in solution when they dissociate

bronsted-lowry acid

H+ donor

bronsted-lowry base 

H+ acceptor 

characteristics of strong acids

completely dissociate in water, forming hydronium ions and anions

characteristics of weak acids

partially dissociate c

characteristics of strong bases

completely dissociate in water to give an aqueous solution of a metal ion and a hydroxide ion

characteristics of weak bases 

partially dissociate 

most common contain nitrogen 

neutralization

when a strong acid and strong base mix

a double exchange reaction

characteristics of antacids

used to neutralize excess stomach acid (HCl)

when they are carbonates being used to neutralize acid, the reaction produces a salt, water, and CO2 gas

chemical equilibrium

the balance of the rates of reactions

• ex: the rate of the formation of ammonia and the rate of reformation of nitrogen and hydrogen gases become equal in the generation of ammonia

indicated by the forward and reverse arrow

no net change in amounts

equilibrium constant (K)

the ration of products to reactants

a characteristic of equilibrium reactions at a given temperature

[products]/[reactants]

• superscripts are from coefficients

K = 1

equal amounts of products and reactants 

K > 1

products predominate

K < 1

reactants predominate

Le Chatelier’s principle

applying stress to the equilibrium will cause the rate of the froward or reverse reaction to change to offset the stress and regain equilibrium

example: N2 (g) + 3H2 (g) ←→ 2NH3 (g)

• adding more N2 will cause the equilibrium to shift right

• removing 3H2 will cause the equilibrium to shift left

same rules apply for removing or adding heat