pH water.

To know the pH of different water samples we use the "cresol red" , it's a simple experiment : we pour different water for example sea water, soapy water, hepar water, acetic acid, tap water, distilles water.

Procedure:

- We have to remove around 5mL of a water sample to a test tube
- Add some drop of cresol red in the test tubes and compare with the pH color indicator.
- Do the same experiment with the thymol blue.

Hard water and soap

Hard water and soap

 

 PROCEDURE

 

Pour 5mL of distilled water into each of the empty test tubes ( 2 ).
Add 5g of epsom salts ( magnesium sulfate ) to one of the test tubes.
Stopper or cap and shake the test tube until the epsom salts dissolve.
Add a drop of liquid dish detergent to both test tubes.
Seal the test tubes with their caps or stoppers.
Shake both test tubes

Antoine LEVEQUE Maore MARTINEZ
 1STL - 2017

Hard Water

Today, we're going to test the hardness of water.
We need some reagents:

We carry out titration:

 

 eriochrome turned from pink to blue:

 

With tap water, we need 1 mL of EDTA
With Hepar water, we need 19 mL of EDTA.
With sea water, we need 75 mL of EDTA

So:
sea water is very very hard!
tap water is not that hard.

Hugo, Mathéo 1STL

How to measure a pH solution ?

How to measure a pH solution ?

There are many ways to measure pH :

with a color indicator :  

thymol blue and cresol red :

 with a pH paper :

with the pH meter :

the most precise way to measure pH solution is the pH meter because it measures more precisely than other ways.

Sohail & Anthony

 

Hard water

Today, we're going to test the hardness of water.
We need some reagents:

We carry out dosage experiment:

 

 eriochrome turned from pink to blue:

 

 
With tap water, we need 1 mL of EDTA
With Hepar water, we need 19 mL of EDTA.
With sea water, we need 75 mL of EDTA

So:
sea water is very very hard!
tap water is not that hard.

Hugo, Mathéo 1STL

Sam at the lab !

Water pH

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