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THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.
THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR QUIZZES and TESTS.
STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR TEXT BOOKS AS PER THE COURSE SYLLABUS
Acidity and pH
LESSON # 6
-e
-e-e-e
-e
-e
-e -e
-e-e
Na
Chloride ion (Cl ) - Sodium ion (Na )
+
+ 11 + 17
-e
-e-e-e
-e
-e
-e -e
-e-e
-e
-e
-e
-e
-e
-e
-eCl
e -
Sodium Chloride
pH
-e
-e-e-e
-e
-e
-e -e
-e-e
-e
-e
-e
-e
-e
-e
-eCl 17
-
pH
+1 p0 n
+
H
-e
-e-e-e
-e
-e
-e -e
-e-e
-e
-e
-e
-e
-e
-e
-eCl 17
-
Hydrogen Proton + Chloride anion -
Hydrochloric Acid (HCl)
pH
+1 p0 n
+
H
Cl_
Na+
Salt
Cl_
H+
AcidHydrogen
proton
An acid is a substance that yields hydrogen protons when put in aqueous solution
Cl_
Na++
Cl_
H+
+
+
+
+
+
+ +
- -
-
-
-
-
-
-
+
+
pH
H+
- +
H Cl
Acidity
Neutral Acidic Basic
Pure water Lemon juice Oven cleaner
H+H+
H+
H+ H+
H+OH
-
OH-
OH-
OH-OH
-
H+
Hydrogen proton
OH-
Hydroxyl group
It makes substances acidic
It makes substances basic
A C I D:
ACID
It is a substance that yields hydrogen protons when put in aqueous solution (proton donor)
pH
H +
H +
H +
H +H +
H +
H +
H +
H +H +
H +
H +
H +
H +
H +
ACIDIC
WATER BECOMES ACIDIC
H+
BASE
BASE
: It is a substance that accepts hydrogen ions when put in aqueous solution (proton acceptor)
pH
OH -OH -
OH -
OH -OH -
OH -OH -
OH -
WATER BECOMES BASIC
BASIC
Most bases accept hydrogen protons because they yield hydroxide groups, which combine with hydrogen to form water molecules
+-OH + H H O2
BASE
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
OH-
It is a substance that accepts hydrogen ions when put in aqueous solution (proton acceptor)
BASE:
H +
H +H +
H +
H +H +
H +
H +H +
H +H +
H +
H +
H +H +H +
H +H +
pH
A c i d i t y i n c r e a s e s
The grade of acidity is proportional to the concentration of hydrogen protons H +
The pH scale Allows us to Quantify How Acidic or Basic Compounds are
The pH is a scale used to quantified the level of acidity or concentration of hydrogen ions
+HIs the pH = ? It is not
HpH =+
- log
pH
How the acidity is quantified?
HpH =+
- log
When the concentration of H increases, the pH decreases
+
When the concentration of H decreases, the pH increases
+
H+
Acidity pHand
H+
Acidity pHand
Acidic Basic
Lemon juice Baking soda
H+H+
H+
H+ H+
H+OH
-
OH-
OH-
OH-OH
-
H+ H
+High
Acidity High
pH Low
Low
Acidity
pH
Low
High
pHAcidic
Basic
Neutral
H+
H+
Lower
Higher
When a solution becomes more acid, its pH drops
When a solution becomes more basic, its pH rises
Ex: Solution 1 is more acid than solution 2. Therefore, pH of solution 1 is _________ than pH of solution 2
Ex: Solution 3 is less acid than solution 4. Therefore, pH of solution 3 is _________ than pH of solution 4
Ex: Solution 5 is more basic than solution 6. Therefore, pH of solution 5 is _________ than pH of solution 6
Ex: Solution 7 is less basic than solution 8. Therefore, pH of solution 7 is _________ than pH of solution 8
pH
HpH =+
- log
Solution 1 is ____ times more acid than solution 2
Solution 1 is ____ times more acid than solution 3
Solution 1 pH: 7
Solution 2 pH: 8
Solution 3 pH: 9
pH
H +
H +H +
H +
H +H +
H +
H +H +
H +H +
H +
H +
H +H +H +
H +H +
pH: ___ pH: ___ pH: ___ pH: ___
Solution 1 Solution 2 Solution 3 Solution 4
When a solution becomes more acid, its pH drops
6 5 4 3
When a solution becomes more basic, its pH raises
M o r e a c i d
M o r e b a s i c
pH
pHpH
Acidic
Basic H+
H+
Higher
Lower
pH
pH
Acidic
Basic H+
H+
Higher
Lower
pH
pH
H+
H+
Higher
Lower
pHDoes not change
pH
pH
How the pH is measured ?
pH
Why does pH matter ?
Because living things are very sensitive to changes in the pH.
Ex: The pH of human blood normally ranges from 7.35 - 7.45. If pH drops under 7.35 the persons has an acidosis. If the pH raises over 7.45 the person is in alkalosis.
pH below 7 can produce coma and death
pH above 7.8 can produce uncontrollable and sustained skeletal muscle contraction and death
pH
Abnormal fluctuations in pH can damage cells and tissues by:
1- Breaking chemicals bounds
2- Changing the shape of proteins, which consequently lose their functions.
3- Altering cellular functions
pH
Buffers resist changes in pH because they can remove or release hydrogen ions
If the concentration of H buffer system remove H and the pH does not change
+ +
If the concentration of H buffer system releases H and the pH does not change
+ +
Buffer is a chemical system that resists abrupt and large swings in the pH of body fluids
Homeostasis of acid-base balance is carefully regulated by chemical systems called buffers
pH
pH
pH
H + pH
pHOH-
WATER
pH
pH
H + pH Does not change
OH-
pH Does not change
Buffering Solutions
