Download a mean to learn many words used in everyday English, not

Something about
CALCIUM CARBONATE
IN NATURE
A lab activity for more than a
purpose: it can be used as:
1. an example of a chemical reaction
2. a way to tell the composition of many
specimens
3. a mean for considering common aspects of
different features in nature
4. introduction to the study of rocks
5. an introduction to part of the rock cycle
6. a mean to learn many words used in
everyday English, not only in science
What you need: materials list
Some calcium
carbonate
from the lab
A dropper and
some diluted
hydrocloric
acid
Some flour / talc /
white powder of
some sort
and
samples of rocks
and hard
mineral parts of
many
organisms, as in
the following
pictures
Minerals
Sedimentary
rocks
Calcite
aragonite
black-limestone
Metamorphic
rocks
marble
..ait
limestone
Stalactite
travertine
..in
Alabaster or
stalagmitic limestone
coral-reef
Sea urchins
(Echinodermata)
algae
Mollusks shells
Foraminifera
Vertebrates skeletons:
(10%....)
Egg shell
What to do: directions
Drop some acid on each
object, starting with
calcium carbonate
and flour
Results: observe what happens
• Positive control test with
calcium carbonate: under
the action of hydrocloric
acid a bubbling release of
gas takes place
• Negative control test with
white powder:
no release of gas
• Positive test for minerals
and rocks shown in the
pictures with the exception
of vertebrates skeletons
Results discussion 1
What Causes the Fizz?
CaCO3 + HCl
CO2 + H2O + Ca++ + Cl-
On the left side of this reaction calcium carbonate
CaCO3 is in contact with hydrochloric acid (HCl).
These react to form carbon dioxide gas (CO2), water
(H2O), dissolved calcium (Ca++) and dissolved
chlorine (Cl-).
The carbon dioxide bubbles that you observe are
evidence that a reaction is taking place. When that
occurs, calcium carbonate is present.
http://geology.com/minerals/acidtest.shtml
website
The "Acid Test" for Carbonate
Minerals and Carbonate Rocks
Results discussion 2
Specimens which
react as the CaCO3
sample are
composed very
likely of that
compound.
Or:
How to recognize calcium
carbonate
The bubbling
release of
carbon
dioxide gas
tells us
that….
Results discussion 3
3 - a mean for considering common
aspects (CaCO3) belonging to
different features in nature
Results discussion 4, 5
• 4 an introduction to the study of the
genesis of rocks
• 5 an introduction to part of the rock
cycle
Results discussion 6
6 - a mean to learn many words
used in everyday English, not
only in science: coral reef, sea
urchins, marble, limestone…….
Students and teacher will look for
“A little text for each specimen”