LAB: INVESTIGATING PH OF VARIOUS HOUSEHOLD PRODUCTS

O B J E C T I V E I S T O D E T E R M I N E T H E P H O F C O M M O N H O U S E H O L D S U B S T A N C E S A N D U S E T H I S I N F O R M A T I O N T O I D E N T I F Y T H E S U B S T A N C E A S A N A C I D I C , B A S I C O R N E U T R A L S O L U T I O N .

VOCABULARY BUILDING: BE SURE THAT YOU CAN DEFINE THESE TERMS BEFORE DOING THE LAB

Solvent

Solute

Solution

Aqueous

Dissociate

Hydrogen ion

Hydroxide ion

Neutral Solution

Acidic Solution

Basic Solution

WATER IN A GLASSHOW DO THE MOLECULES APPEAR?

Above is a diagram of the way in water molecules can look in the glass to the left. The water molecules breaks into ions, hydroxide and hydrogen.

Diagram below shows Water molecules with 2 hydrogenAtoms and 1 oxygen atom

Need an “indicator” which is something that detects the presence of a certain substance

MATERIALS

Paper Indicators to determine if solution is acid/base:

1. pH paper *indicates the presence and amount of H+

2. litmus red paper3. litmus blue paper

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SET UP

FOR T

HE LAB

Test

tubes

con

tain

var

ious

house

hold s

ubstan

ces

Above you can see the three types of papers. The pH paper is the light yellow coloredpaper. The red paper is red and the blue paper is blue. A beaker of distilled water is available to clean the stirring rod after each application of a substance on the paper. Preventing contamination of solutions is very important.

Solution Guess Acid Base Neutral

Milk x

Vinegar x

Egg white

x

Orange Juice

x

Ammonia x

Unknown #1

x

Unknown#2

x

Data Table 2 indicates the type of solution for a given householdproduct

Unknown #1 – Baking Soda WaterUnknown #2 – Lemon Juice

Solution pH Paper Litmus Red

Litmus Blue

Milk 6-7 Red Red

Vinegar 1-2 Red Red

Egg white 7-8 Blue Blue

Orange Juice

4 Red Red

Ammonia 9 Blue Blue

Unknown #1

8-9 Blue Blue

Unknown #2

1-2 Red Red

Data Table 1: Color of Paper Indicator With a Given Household Product

PART B: NEUTRALIZATION REACTION

Phenolphtalein is another indicator. It will go from colorless to pink if the solution becomes basic. What does that mean to say a solution is basic? In this part, you willuse this indicator to demonstrate a neutralization reaction.

EQUATION FOR A NEUTRALIZATION REACTION

In our lab, we used ammonia to create a basic solution. Then we addedVinegar until the solution was not longer basic.