P&P notes Chapter 7 【acids & bases】

CHAPTER 7 : ACID AND BASE

7.1 ACIDS & BASES
A. Acids
1. What is acids ?
A chemical substances which _______________ in water to produce __________________ _____ .

Example: HCl H+ + Cl-



2. The _________________ are responsible for acids to show their properties.
3. Acids classified as ____________ acid (produce I mole of H+) &
____________ acid (produce 2 mole of H+), base on its bacidity.

Example: HNO3 H+ + NO3- (monoprotic acid)

H2SO4 2 H+ + SO42- (diprotic acid)

4. Bacidity : The number of ______________ hydrogen atoms per molecule of an acid.

B. Bases
1. What is bases ?
A chemical substances which _______________ in water to produce__________________ _____ .


Example: NaOH Na+ + OH-

2. Base reacts with acid to form a _______ and _______ only.

Example: NaOH + HNO3 NaNO3 + H2O

3. The _________________ are responsible for alkalis to show their properties.

4. Difference of bases & alkalis :
- some bases can dissolves in water
- soluble bases are known as __________.



C. Role of Water
- acids & bases only show their properties when __________ in water
- because without water, acids & bases still exist as ___________ and no H+ @ OH- ions present.
- but in water, acids & bases __________ to form H+ @ OH- ions.



D. Indicators
- gives colour depend on the pH of the solution
- could be in solid form or liquid form
INDICATORS ACIDIC NEUTRAL ALKALINE
Litmus paper Red - Blue
Universal indicator Green Green Blue
Methyl orange Red Orange Yellow
Phenolphthalein Colorless Colorless pink


E. Physical Properties
ACIDS PROPERTIES ALKALIS
Taste
Turn moist litmus paper
Ph value
F. Chemical Properties


1. react with bases to form ___________ and ___________.
2. react with reactive metal to form ___________ and _______________.
3. react with carbonates to form ____________, _____________ and _____________________.
Examples:
1. HCl + KOH
2. HCl + Mg
H2SO4 + Pb
3. HCl + MgCO3
HNO3 + ZnCO3




1. react with acids to form ___________ and ___________.
2. mix with ammonium salt and heated, ____________ liberated.
3. adding to most of the metal ion solution, a to form _______________.
Reason: most of the metal hydroxide are insoluble in water.

Examples:
1. HCl + NaOH
2. NH4Cl + Ca(OH)2 ∆


7.2 THE STRENGTH OF ACIDS & BASES

Strong acids Strong alkalis


Acidic increasing Neutral Alkaline increasing




** Why strong acids has lower pH & strong alkalis has higher pH ??


Strong Acids Weak Acids
- Ionises completely in water - ionises partial in water
- Large numbers of H+ ions - few of numbers of H+
- [H+ ] high - [ H+ ] low
- pH value - pH value

**********************************************************************
Strong Alkalis Weak Alkalis
- ionises in water - ionises in water
- large numbers of H+ ions - few of numbers of H+
- [ OH- ] high - [ OH- ] low
- pH value - pH value

7.3 CONCENTRATION OF ACIDS AND ALKALIS
1. Molarity - the amount of dissolved substance in 1dm-3 of solvent to form a solution.
2. Unit - ________________ / _________¬¬¬¬¬¬¬¬¬¬________
1 dm-3 = 1000 cm-3

3. the molarity of a solution does not determine whether it is strong @ weak acid

4. No. of moles = M V ; M = molarity ; V = volume
1000
* exersicises

5. Preparation of Standard Solution
- a solution which has a _________________________________.
- prepared by ________________________.
* exersicises

6. Dilution
- prepare a less concentrated solution
M1V1 = M2V2 M1 = initial molarity ; V1 = initial volume
M2 = final molarity ; V2 = final volume
* exersicises


7. Molarity Vs pH value
Molarity / Concentration  [ H+] in acids pH
 [ OH-] in alkalis pH




7.4 NEUTRALISATIONS
1. the reaction between _________ and __________ to produce salt & water.
2. H+ from acids combine with OH- from alkalis to form water molecules.
H+ + OH-  H2O

3. Acid – Bases Titration
- a quantitative analysis methode to determine the volume of an acid to neutralise an alkali
-
4. End Point – point which neutralization done completely.
5. End point can be determined by : indicators / electrical conductivity