CHAPTER 7: ACIDS AND BASES
1.0 INTRODUCTION
Acids and bases play a central role in chemistry because every chemical reaction can be
classified as an acid-base reaction. Acid-base is important to us on a practical level as well,
outside of laboratory chemical reactions. Our food can be divided into acid and bases example,
orange has a sour taste (acid) while coffee has a bitter taste (base). In this chapter, we will start
by introducing fundamentals of acid-base. The knowledge of acid and base provided for
objective means of classifying household substances and everyday items.
Substance that have asid and alkali properties.
Acids if define as substances that dissolve in water to form an aqueous solution and producing
H+ ions while a base is define a substances that dissolve in water to form an aqueous solution
and producing OH- ions. Bases that dissolve in water are call alkaline. Acid and base can only
show their properties with water. The properties of acid and base are:
An acid and alkaline can be categorized according to the degree of dissociation in water. If an
acid and alkali dissociation completely in water, they were categorized as strong acid or strong
alkali. If an acid and alkali partially dissociation in water, they were categorized as weak acid or
weak alkali. An acid also can be categorized according to the basicity, if one mole of H+ was
produce, it will be called as monoprotic acid and 2 mole of H+ was produce, it will be called as
diprotic acid. The higher the value of H+, the acid are strong acid.
The pH scale is a measure of how acidic or basic a chemical. The nomenclature pH means “the
potential of hydrogen” and refers to the ability of a chemical to donate or accept hydrogen ions
to other chemicals. Acids donate hydrogen ions while bases can accept them. The pH scale
ranges from 1 to 14. The pH of 7 is neutral – it is neither basic nor acidic. The pH indicators are
chemicals that change the colour of substances when added to an acid or base.
2.0 SCIENTIFIC CONCEPT
3.0 CONSTRUCTING A DIAGRAM
Based on the properties of acid and base, “acid and base only shown their properties with
water”. There are several ways to introduce an acid and base to student, in this chapter we only
choose:

Engaging phase – An introduction what is an acid and base

Empowering phase – The degree of dissociation of an acid and alkali

Enhance – pH of acid and alkali
4.0 3E’S ELEMENT (ENGAGING, EMPOWERING & ENHANCING)
4.1 ENGAGING PHASE
Activity:
Teacher shows a video from the internet to attract student’s attention to the topic which will
be discussed. They are required to watch the video carefully. After showing the video,
student will be asked some questions in order to elicit their prior knowledge.
Source: Acid + Bases made easy!
Retrieved from: http://www.youtube.com/watch?v=kPd_OZ1t_aY
Source: Coke can in the acid and base
Retrieved: http://www.youtube.com/watch?v=WnPrtYUKke8
Questions:
1. What is an acid?
2. What is a base?
3. What is mean by strong acid or strong base?
4. What is mean by weak acid or weak base?
5. Which one is more dangerous between an acid and a base?
Simple answer:
1.
Acid is a proton donor
2. Base is a proton accepter
3. Strong acid/ base is a substance that can release a proton easily/ accept a proton
easily due to the weak bonding in the substance
4. Weak acid/ base is a substance that can release a proton (small quantities)/ accept a
proton due to the strong bonding in the substance
5. Base (Alkali)
4.2 EMPOWERING PHASE
Activity:
 Teacher need to have an internet connection
 Internet access to :http://phet.colorado.edu/en/simulations/category/chemistry
 Teacher able to demonstrate about the acid-base solution using the simulation above ;
Retrieved from: http://phet.colorado.edu/en/simulations/category/chemistry
Activity sheet:
Instruction:
The concentration of the acids and bases used in the
at 0.010 (10-2) Molar.

Begin with a strong acid and lower the pH probe into the beaker. What is the pH of this solution?

Test this strong acid with both pH paper and the conductivity probe. What colour does the pH indicator
become? Is this strong acid an electrolyte? Does current travel through this solution?

Repeat the above tests with the weak acid, the strong base, and the weak base, and water. Collect your
observations in the table below:
Strong Acid
pH meter read
(value)
pH paper
(color)
Conductivity
(bright/dim/none)
Weak Acid
Strong Base
Weak Base
Water
Exists as Mostly
(ions/molecules)
What conclusion that you can made from this activities?
Sample answer:

pH of the solution is 2.00

The colour of pH indicator is red. Strong acid is an electrolyte and current can travel through the solution.
Strong Acid
Weak Acid
Strong Base
Weak Base
Water
pH meter read
(value)
2.00
4.50
12.00
9.50
red
orange
blue
green
7.00
pH paper
(color)
orange
yellowish
Conductivity
(bright/dim/none)
bright
dim
bright
dim
none
ions
molecules
ions
molecules
molecules
Exists as Mostly
(ions/molecules)
Conclusion: Strong acid/ base are good conductor and exist as ions in the solution.
4.2 ENHANCING PHASE
Activities:
1. Students are divided into group (3 students per group). Each group will be given a Worksheet 1 and
Worksheet 2.
2. In a group, applying all concepts that had been learned.
3. Teacher will act as a facilitator (observe and correct student mistake) while they completing the
Worksheet 1 and Worksheet 2.
4. After finishing the Worksheets, each group will be presenting their friends findings (other groups) in
front of the class.
Worksheet 1
1.
What are three properties of acids?
2.
What are three properties of bases?
3.
Name 2 acids and their uses.
4.
Name 2 bases and their uses.
5.
Describe one way you can safely determine whether an unknown solution is an acid or base?
6.
Describe the pH scale. What is the pH range of an acid? What is the pH range of a base?
Label as either true (T) or false (F):
_____ 1.
Acids will not conduct electricity.
_____ 2.
Bases will conduct electricity.
_____ 3.
Acids taste bitter.
_____ 4.
Bases will turn red litmus paper blue.
_____ 5.
Acids react with some metals to produce hydrogen gas.
_____ 6.
Acids will turn phenolphthalein (PHTH) indicator pink.
_____ 7.
An indicator is a substance which changes colors in acids and bases.
_____ 8.
Acids will turn blue litmus paper red.
_____ 9.
Bases feel slippery.
_____ 10.
The pH of water is 7.
Sample answer:
1. sour, change wet blue litmus paper to red and pH below than 7
2. bitter, change wet red litmus paper to blue and pH above 7
3. Hydrochloric acid - digestion in stomach and Citrus acid – use in beverage to give sour taste
4. Sodium hydroxide – manufacture of soap and Calcium hydroxide – manufacture of bleaching
powder
5. Using a litmus paper, if red litmus paper turn blue it is a base and if the blue litmus paper turn red
it is an acid
6. The pH scale measures how acidic or basic a substance is. The range of acid is 1 to 6 and 8 to
14 for base
Label as either true (T) or false (F):
___T__ 1.
Acids will not conduct electricity.
___T__ 2.
Bases will conduct electricity.
___F__ 3.
Acids taste bitter.
___T__ 4.
Bases will turn red litmus paper blue.
____T_ 5.
Acids react with some metals to produce hydrogen gas.
____F_ 6.
Acids will turn phenolphthalein (PHTH) indicator pink.
____T_ 7.
An indicator is a substance which changes colors in acids and bases.
___T__ 8.
Acids will turn blue litmus paper red.
___T__ 9.
Bases feel slippery.
____T_ 10.
The pH of water is 7.
Worksheet 2
1. When the concentration of hydroxide ions is equal to the concentration of hydrogen ions, what is the pH?
Is such a substance neutral, acidic, or basic?
2. What are hyrogen ions? Hydroxide ions?
3. What scale measures how acidic or basic a substance is?
4. What substance changes color in the presence of acids and bases?
5. What does the pH measure?
6. Write the formula for: hydrobromic acid. _________ and aluminum hydroxide. ____________
7. Name these substances: HF._______________________ Ca(OH)2. __________________________________
8. Write a reaction for the ionization of hydrochloric acid.
9. Write the reaction for the ionization of potassium hydroxide.
10. HCl ionizes completely in water. Is it a strong or weak acid?
11. What happens to an acid or base when it ionizes?
12. When pollutants are absorbed by ____________in the air, __________________ is created in the rain.
13. An acid has a pH range of: __________ A base has a pH range of : _____________
14. Using the table below, identify each of the properties as belonging to an acid or a base or both by putting
a check mark in the space.
Property
Bitter taste
Sour
Slippery
acid
base
both
Corrosive
Accepts H+
HNO3
Forms H3O+ ions in water
Reacts w/indicator & causes color change
KOH
Donates protons
Greater concentration of hydronium ions
Rain
Sample answers
1.
7, neutral
2.
H+, OH-
3.
pH
4.
pH paper
5.
the concentration of hydrogen ions
6.
HBr, Al(OH)3
7.
hydrofluoric acid, calcium hydroxide
8.
HCl (aq) → H+ (aq) + Cl-(aq)
9.
KOH (s) → K+ (aq) + OH-(aq)
10.
strong
11.
it breaks into its cations and anions
12.
moisture, sulfuric acid
13.
<7, >7
14.
Property
acid
Bitter taste
Sour
base
X
X
Slippery
X
Corrosive
X
Accepts H+
HNO3
both
X
X
Forms H3O+ ions in water
X
Reacts w/indicator & causes color change
X
KOH
X
Donates protons
X
Greater concentration of hydronium ions
X
Rain
X
5.0 REFLECTION
1. The student will made a conclusion what is an acid and base is all about.
2. The simulation techniques which had been used throughout the teaching and learning
process are effectively as the student can define the acid and base correctly.
6.0 REFERENCES
Acid + Bases made easy!, retrieved on April 5th, 2014
from: http://www.youtube.com/watch?v=kPd_OZ1t_aY
Coke can in the acid and base, retrieved on April 5th, 2014
from: http://www.youtube.com/watch?v=WnPrtYUKke8
Acid and base solution, retrieved on April 5th, 2014
from:http://phet.colorado.edu/en/simulations/category/chemistry
SKP 6024
TECHNOLOGY AND INNOVATION IN TEACHING AND LEARNING CHEMISTRY
ASSINGMENT 5 : SIMULATION/MODELLING
CHEMISTRY FORM 4
CHAPTER 7 : ACIDS AND BASES
GROUP MEMBERS :
AZMA BINTI MOHAMAD AMIN
M20131000598
SYAZWANI BINTI CHE SEMAN
M20131000606
LECTURER
: CIK HAJAH ASMAYATI BINTI YAHAYA
TASK
: ASSIGNMENT 5 (TEACHING MODEL)