Distinguish between concentration and strength of Acids and Bases

1. VCE CHEMISTRY
Acids & Bases
Strength v Concentration
Objective:
To distinguish between strength &
concentration of acids & bases
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2. 1.What is an acid & a base ?
2. Name 3 Acids & 3 Bases
3. Can you write ionisation of:
Sulphuric Acid
Sodium Hydroxide
Discuss for 1 Minute in Pairs
No referring to Notes or Computers

3. Brønsted-Lowry Theory:
Acids are proton donors (Think AD)
Bases are proton acceptors
Arrhenius Theory:
Acids generate H+ ions
Bases generate OH- ions.

4. Sulfuric Acid
H2SO4 2H+ + SO4
Sodium Hydroxide
NaOH Na+ + OH-
2-

5. Reversible – remember constantly
dissociate & reassociate

6. Strength Concentration
Acids & Bases are measured by:

7. Strength
Base Basic Solution
Acid Acidic Solution

8. In water an acid or base molecule can break apart
DISSOCIATION
Acids form the hydronium ion(H3O+ also see H+)

9. Dissociation in solution

10. Strength
The degree of dissociation defines strong or weak acid.
Which is Strong or Weak acid ?
-

11. Strength
Strong acid
Weak acid
H O
H
OF
H
H
H
H H F F
+ + +
Weak acid Water hydronium ion
-+
ions

12. Strength
Strong acid or base completely dissociates in solution
Weak acid or base only partially dissociates in solution.
H O
H
OF
H
H
H
H H F F
+ + +
Weak acid Water hydronium ion
-+
ions

13. Strong orWeak ?

14. Strong orWeak ?

15. Concentration
Number of moles per volume within solution
Amount of acid or base in solution

16. Less Concentrated means less
Na+ OH
_
but still strong base
Less Concentrated means
less H3O+ Cl- but still strong acid

17. In pairs, draw a beaker & show with ions;
Highly Concentrated Weak Acid (HF)
Weakly concentratedWeak Acid
Weakly Concentrated Strong Acid (HCl)
Highly concentrated Strong Acid

19. Review
Strength - Dissociation in soln
Strong acid completely dissociates
Weak acid partially dissociates
Concentration - Amount in soln
Weak low amount
High high amount

20. HOPE YOU ENJOYED THE LESSON!