Acids and Bases
What is the name of the following substance?
H2SO4
sulfuric acid
potential for hydrogen
- scale from 0-14
What does Kw stand for?
equilibrium constant of water
What is the conjugate base of HCl ?
Cl-
HCl is a strong acid so it gives up the H+ ion
What makes weak acids and bases different from strong ones?
They do not dissociate in solution
- initial concentration is very close to concentration at eq
Is the following an acid or base?
HCN
acid
- has H+ to give
What is the formula for pH and pOH?
pH=-log[H+]
pOH=-log[OH-]
What is the Bronsted - Lowry definition of a base?
a molecule that can accept an H+
- normally has OH in its formula or a negative charge
What happens to strong acids or bases in solution?
dissociate into ions
When given a problem how do you know if a solution is an acid or base?
Ka -> acid
Kb -> base
Is the following an acid or base?
NH3
base
ammonia, can gain a 4th H to form ammonium NH4+
What is the relationship between [H+] and [OH-]?
[H+][OH-]=Kw=1.1 x 10^-14
What is the value of Kw?
1.1 x 10^-14
If a solution is a strong base what is the relationship between its molarity and [OH-]?
same because the solution will dissociate
Name an example of a weak acid and a weak base.
carbonic acid : H2CO3
cyanide ion: CN-
What type of acid or base is the following compound
CH3COOH
weak acid
- acetic acid
What is the relationship between pH and pOH?
pH + pOH=14
What are the two rules for determining if an acid is strong or weak?
1. Halogen with Hydrogen
2. There are at least 2 more oxygens than hydrogens
What is special about water in ICE charts?
leave it out bc it is a pure liquid or solid
When given the molarity of a weak acid or base where does that value go in the ICE chart?
initial concentration of acid/base
Is water an acid or base?
It depends on what it is paired with
- paired with HCl -> base
- paired with KOH -> acid
If a solution is acidic what will its concentration of H+ be relative to its concentration of OH-?
[H+]>[OH-]
low pH
Which of the following is more acidic?
Orange juice or stomach acid
stomach acid pH~2.5
What is the pH of a 0.325M KOH solution?
Kb=4.4 x 10^-6
KOH. H2O. K+. OH-
I 0.325. - 0. 0
C. -x - +x. +x
E. 0.325-x - x. x
4.4 x 10^-6=x^2/0.325 -x
(4.4 x 10^-6)(0.325 -x) = x^2
(1.4 x 10^-6) - (4.4 x 10^-6)x = x^2
Quadratic formula or graphing calculator
x = 1.2 x 10^-3 = [OH-]
[H+]=1.2 x 10^-3/1.1 x 10^-14
= 9.2 x 10^-12
pH=-log(9.2 x 10^-12)
pH=11
There is a 0.112 M CH3COOH solution with a pH of 4.32. What is the Ka of this solution?
4.32 = -log [H+]
10^-4.32 = [H+] = 4.79 x 10^-5=x
CH3COOH H2O. CH3COO- H+
I 0.112 - 0. 0
C -x - +x +x
E 0.112-4.79 x 10^-5 4.79 x 10^-5. same
0.112
Ka= (4.79 x 10^-5)^2/0.1122.05 x 10^-8