1. 15.4 NOTES Acids and Bases

2. C.4 Structure Determines Properties
Arrhenius definition of acids and bases
Acid – a substance that generates hydrogen ions when dissolved in water
Base – generates hydroxide (-OH) when dissolved in water
“OH is your home base”
Combining the two creates a hydronium ion (H3O+)

5. Most acids have hydrogen atoms that can be released in water
H ____, H2_____, H3_____
Ex: HNO3, H2S, H3PO4
Form anion and hydronium when dissolved in water

6. Bases have a cation and a hydroxide ion
___OH, ___(OH)2, ___ (OH)3
Ex. NaOH, Sr(OH)2, Al(OH)3
Form cation and OH- when dissolved in water

7. Neutralization
Mixing equal amounts of acid and base, forming water and a salt as the products
A salt is made from a cation (+) and an anion (-) charge
Neutral solutions
Concentrations of hydronium and hydroxide
are small and equal

8. Acidic solutions (H+)
Hydronium concentration is higher than hydroxide (OH-)
Very acidic solutions have very large hydronium concentrations
Basic solutions
Hydroxide(OH-) concentration in higher than hydronium (H+)
Very basic solutions have very large hydroxide concentrations

10. The pH scale
Related to hydrogen/hydronium concentration present in solution
pH stands for power of hydronium ion, where power is the power of 10 that expresses the hydrogen ion’s molar concentration

11.
Closer to 0, the more acidic the substance is, the closer to 14, the more basic the substance
pOH can measure alkalinity, or how basic the solution is or how much hydroxide is present
The scale is opposite the pH scale; bases are close to O and acids are close to 14

12. You can look at this as a number line:

13. C.7 Interpreting the pH Scale – Complete the following chart.
Substance pH
pOH
Acid, Base, or Neutral
Milk
6.0
8.0 
Acid 
Stomach Fluid
 1.0
13.0
 Acid
Drain Cleaner
 Base
Cola Drink
 3.0
11.0

14. C.8 Strengths of Acids and Bases
Ionization – when acids and bases break apart into ions

15. Strong acids and Strong bases- break apart completely in water and don’t reform the original acid or base
There are 6 strong acids
HI, HBr, HCl, HNO3, H2SO4, and HClO4, all other acids are weak
Strong bases start with a cation that is in group 1 or 2 on the periodic table
LiOH, NaOH, KOH, RbOH, Mg(OH)2, Sr(OH)2, Ba(OH)2
Weak acids/bases- only partially break apart in water

17. Reversible reactions
Weak acids can proceed at an equal rate in each direction
Dynamic equilibrium
Forward reaction goes at the same rate as the reverse reaction
Forward/reverse rates are equal, not the amounts of products
They take the same amount of time to undergo the reaction
Strong acids/bases typically are not reversible

18. C.10 Acids, Bases, and Buffers
Some lakes/rivers aren’t affected by acid rain
Buffers
Substances capable of neutralize an acid or base without changing the pH
need:
To neutralize an acid, you add a base
To neutralize a base, you add an acid
Natural buffers are found in blood and stomach

20. Strength vs. Concentration
Strength – measure of how many ions are produced when acid/base is dissolved in water
Strong acid/base – all (or nearly all) acid/base have reacted with water to produce ions
Weak acid/base – acid/base has partially formed ions in water

21. Concentration – measure of how many particles (molecules or ions) are dissolved in a solutions
Concentrated acid/base – a very large number of particles are dissolved
Dilute acid/base – a low number of particles are dissolved

22. True or false
It is possible to have a strong acid that is dilute
True
It is possible to have a weak base that is concentrated true