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.
