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Activities – sequence n° 3 : Chemistry and the environment
Sequence n° 3: chemistry and the environment
ACTIVITY 1 :
pH of sea water
Part 1: Introduction
Video « Acidification » http://www.youtube.com/watch?v=-3TF9qkQ8R4 : from 0s-57s
Source : Plymouth Marine Laboratory
Question 1 : What is the main idea ?
____________________________________________________________________________________
Question 2 : Which problems are linked to oceans ?
____________________________________________________________________________________
.
Part 2: pH of sea water
Experiment: Sea water in a beaker
SEA
WATER
Question 3 : Which value do you expect ?
Why do you think this value is different
from 7 ?
pH = _____
Sources : http://commons.wikimedia.org/wiki/File:Tortue_imbriqueeld4.jpg
Et
http://commons.wikimedia.org/wiki/File:PH_indicator_paper_roll.jpg?uselang=
fr
Part 3 : Composition of sea water
Question 4 : Among the listed ions present in sea water, circle the ones involved in an acid/base couple.
Composition of sea water
page 1
Première STL – ETLV
Activities – sequence n° 3 : Chemistry and the environment
Anions
mol/kg water
chloride ion (Cl-)
Sulfate ion (SO42-)
hydrogen carbonate ion (HCO3-)
bromide ion (Br-)
carbonate ion (CO32-)
hydroxyde ion (HO-)
0,54586
0,02824
0,00177
0,00084
0,00026
0,00001
Cations
sodium ion (Na+)
magnesium ion (Mg2+)
calcium ion (Ca2+)
potassium ion (K+)
strontium ion (Sr2+)
mol/kg
water
0,46906
0,05282
0,01028
0,01021
0,00009
Reference : Encyclopaedia Universalis
Question 5 : Circle the acid base couples involved
Pairs
Pairs
Acetic acid / acetate ion
CH3COOH / CH3COOH2O / HOHCO3-/ CO32HPO42- / PO43H2CO3 / HCO3-
Water / hydroxyde ion
Hydrogen carbonate ion / carbonate ion
Hydrogen phosphate ion / phosphate ion
carbonic acid / hydrogen carbonate ion
page 2
Première STL – ETLV
Activities – sequence n° 3 : Chemistry and the environment
Activity summary
What you must remember :
-
vocabulary associated with the ocean and its constituants
Skills linked to the curriculum:
Compétences
- APP
- ANA
- COM
Capacités à maîtriser
-
Citer des implications de la chimie dans des
études menées sur l’environnement
-
Citer des actions visant à préserver
l’environnement.
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