Shake your Acids, Bases and Salts!

Introduction

We daily use in our life a large number of substances such as lemon, tamarind,

common salt, sugar, vinegar etc. Do they have same taste? You find that some of

these taste sour, some bitter, some sweet and some salty.

Learning Objectives

•To classify the common household substances if they are acids, bases or salts.

•To determine the pH of the substances.

•To describe the result of the investigation and characteristics of each substance.

A Brief Overview of Acids and Bases

http://www.youtube.com/watch?v=tNvP3-174_M

Watch the short clip

Preliminary Task

Search for any substance that you can see outside and inside the

school premises and bring it in the classroom. Be back after 15

minutes.

FacilitatorsHi I’m Super A, I will help you understand Acids!

And you can call me Super S, I will help you understand Salts!

My name is Super B, I will help you know Bases!

Hi Super A!

What is Acid?

Hello Kids! Today we will discuss

AcidAn acid is a substance that gives H+ (Hydrogen) ions

when dissolved in water. They are usually compounds of non metals with Hydrogen and

sometimes Oxygen.

The following are the characteristics of Acids:

• Acids have a sour taste• Acids reacts with metals•Acids contains Hydrogen• Many are poisonous and corrosive to skin.• It has a pH less than 7

Based on the video that you had watched earlier, can you identify the characteristics of an acids?

Some common examples of an Acids are:

1. Explosives

2. Car Batteries

3. Cola

4. VinegarExplosives and car batteries are strong acids

while cola and vinegar are weak acids.

Now, lets go on with Base. A Base is a substance that gives OH- (hydroxide)

ions when dissolved in water. The solution of a base in water is called

an alkali.

The following are the characteristics of Bases:

• Bases usually taste bitter• Strong Bases are also poisonous and corrosive to learning• Bases contains Hydroxide ions• Bases feel slippery•It has a pH greater than 7

Based on the video that you had watched earlier, can you identify the characteristics of a Bases?

Some common examples of Bases are:

1. Drain cleaner

2. Plaster

3. Baking powder

4. Windex glass cleanerDrain cleaner and plaster are strong bases

while baking powder and Windex glass cleaner are weak bases.

When and acid and a base react with each other, the characteristic properties of both are destroyed. This is called neutralization.

General formula for acid base reaction:

Reactions between acids and bases

Acid + Base + SaltH2O

“Salt” means any ionic compound formed from an acid/base reaction

Neutralization

HCl + NaOH → H2O + NaCl

acid + base water+ salt →

An indicator is a compound that will change color in the presence of an acid or base

• Red Litmus paper turns blue in base

• Blue Litmus paper turns red in acid

• Universal indicator (pH paper)

Used for the full pH range

pH stands for “potential hydrogen” and is a measure of how many H+ ions there are in solution.

The MORE H+ there are, the LOWER the pH will be.

pH Scale

Shows the range of H+ concentrations

High H+ concentrationLow H+ concentration

A Salt results when an acid reacts with a base. The H+ and OH- ions combine to form water. This process is called as neutralization.

The non metallic ions of the acid and the metal ions of the base form the salt.

Acid + Base —-> Salt + Water

The following are the characteristics of Salts:

• Salts can be of several different colors• Usually salts are odorless•Salts have pH = 7. They are neutral

Some common examples of Salts are:

1. Toothpaste

2. Kitchen Salt

Activity

Summary Acid is a substance that gives H+ (Hydrogen) ions when dissolved in water. Acids have a sour taste, reacts with metals and contains Hydrogen. Many are poisonous and corrosive to skin. It has a pH less than 7 and turns blue litmus paper to red. Some of the common examples of an acid are car batteries, explosives, cola, vinegar, etc.

While Base is a substance that gives OH- (hydroxide) ions when dissolved in water. The solution of a base in water is called an alkali. It usually taste bitter, contains Hydroxide ions, feel slippery and strong bases are also poisonous and corrosive to learning. It has a pH greater than 7 and turn red litmus paper to blue. Some common examples are glass/drain cleaner, baking powder, plaster, etc.

Salt results when an acid reacts with a base. The H+ and OH- ions combine to form water. This process is called as neutralization. Salts can be of several different color , usually odorless and have pH = 7. Some common examples are toothpaste, kitchen salt, etc.

Assignment

Look for other 15 household substances, check its ingredients

and identify why it is an acid, base or salt. Give its formula if

possible.

Referencehttp://schooltutoring.com/help/three-important-types-of-chemicals-acid-bases-salts/

http://www.shodor.org/unchem/basic/ab/

http://www.knockhardy.org.uk/sci_htm_files/08SALTS.PDF

http://www.slideboom.com/presentations/546519/ACIDS,-BASES-%26-SALTS