Acids & Bases Flashcards
Acid
- A formula that starts with hydrogen (expect for H2O)
- There are two types of acids: oxyacids and binary acids
- They are molecular compounds but act like ionic compounds in water/aqueous solution
Base
- A compound that has OH
- They are ionic compounds
Arrhenius Theory of Acids & Bases
- An acid is a molecular compound that ionizes in water to produce hydrogen
- A base is a ionic compound that dissociates in water to produce hydroxide
Ionization and dissociation
- They both form ions in a solution, but how it happens is different
The strength of an acid and base
- According to Autherius, The strength of an acid and base depends on the extent to which it ionizes and dissociates
- Strong is not the same as concentrated. A strong acid or base can be diluted or concentrated
- Weak is not the same as dilute. Weak acids and bases can be dilute or concentrated
The pH scale
- Does not measure the strength of a acid or base
- pH= Power of hydrogen
- Gives you an indication of the concentration of hydrogen ions in a solution
- The pH is the negative of concentration exponent if you have 1.0
Limitations of Arrhenius Theory of Acids & Bases
Some substances are basic but do not have hydroxide
Ammonia is basic in water but does not have OH
This means the OH is increasing without doing
H + OH –> H2O
The pH scale: Tenfold
- 1 pH unit is a tenfold on changes in acidity or basicity of a solution
- When comparing two pH, you can multiple the differences between them by tenfold (3 times greater/tenfold, 10^3= 1000)
- pH 4 is 1000 greater than pH 7, as 1 x 10^-4 is 1000 greater than 1 x 10^-7
Strong acids
Strong acids completely ionize in water
Strong bases
Strong bases completely dissociate in water
Strong bases and acids
Molecules breaks up into ions
Limited or no acid/base particles left over
Ionization
- Ionization: The creation of new ions in an uncharged molecule
No charges as they have covalent bonds, so there is no ions until in water
Dissociation
- Dissociation: The separation of ions that already exist in a neutral compound
Charges are criss crossed, which means they have ions
Weak Base
Weak bases partially dissociate
Weak Acid
Weak acids partially ionize
Weak acid and base
- Acid particles to beginning and left over are similar
- Percent that they ionize into their ions is very small
H+ Ions
VERY ACID:
* 1.0x10-1 mol/L
* 0.1 mol/L= many H+ per L
* pH = 1
NEUTRAL:
* 1.0x10-7 mol/L
* 0.0000001 mol/L= H+ concentration in pure water
* pH = 7
VERY BASIC:
* 1.0x10-14 mol/L
* 0.00000000000001 mol/L
* few H+ per L
* pH = 14
examples of Strong acids
HCl
HNO3 (aq)
HClO4 (aq)
H2SO4 (aq)
examples of weak acids
organic molecules (lots of C, H and O)
HC2H3O2 (aq)
H3PO4 (aq)
H2CO3 (sq)
HCO2H (aq)
