In O Level Chemistry as well as other major Chemistry Examinations such as ICGSE Chemistry, IB Chemistry and IP Chemistry, and A Levels, we have always encounter LIMESTONE – which is essentially Calcium Carbonate CaCO3(s) in the chemical terms.
Do you know we have many natural occurrence of Calcium Carbonate around us?
This picture was taken 3 years ago when i was on holiday in Melbourne, Australia. And the background is the world famous “The Great Ocean Road”. It is a 243 km stretch of road along the south-eastern coast of Australia and provides some of the most scenic coastline in the world, because of its striking and dramatic natural limestone and sandstone rock formations. These formations have been created by erosion from waves and rain and include Loch Ard Gorge, the Grotto, London Bridge (renamed to London Arch after the ‘bridge’ partly collapsed), and most famously the Twelve Apostles (yeah, can you see those spikes formation in the background? It used to be 12th of them, but when i took this photo, there were only 11 left! hmm..wonder how many left now?)
Another Limestone formation – called the “Elephant Rock”
Interesting isn’t it? There are indeed many things (living and non-living things) that are related to Chemistry Theories and Reactions.
Now, as usual, my style! You have seen the nice nice photos and how chemistry is related to our everyday lives (i call it “Chemistry Phenomenon“). TIME to put on your thinking caps to solve some question.
Question:
(i) What will you get when you heat a beaker of Limestone?
(ii) What will you observe?
PS: Leave your suggested answers in “Leave A Reply” below.
PPS: Anyone here from Melbourne or Australia? I would love to hear from you. =)
There would be the formation of Calcium oxide(CaO) and Carbondioxide(CO2).
What would be observed would be the effervesence of a colourless and odourless gas which turns lime water milky and blue litmus paper red indicating that CO2(g) is present.
The reaction would be:
CaCO3+ heat-CaO+ CO2(g)
hey sean!
how do you approach an acid base titration experiment? And what are the difference between sources of error and experimental error?
Pls reply! :)))
Hi sir!
Can i ask for a simple ivestigatory project and a chemistry related phenomena?
thanks!
Hi, I know that Zinc Oxide turns from white to yellow when heated and then turn from yellow to white when cooled down. Does the same thing occur for Calcium Oxide? I think that there is no colour change as both calcium carbonate and calcium oxide are white in colour.
On a side note, I would like to know how to carry out tests on an insoluble solid. For example, Silver Chloride. It cannot dissociate in water so how do I go about testing for such solids during a SPA test?
Thanks a lot.
Hi Aiden,
I suppose you meant “Limestone is Calcium Carbonate”.
You wont see “effervescence” since there is not liquid/solution.
Effervescence is equivalent to “bubbling effect”. Calcium carbonate is a solid and upon thermal decomposition, you wont see effervescence.
Observation: Since Calcium Carbonate becomes Calcium Oxide, check if there is any colour change to the solid present in the beaker. Think about it.
To Your Academic Success in Chemistry,
Sean
Master Trainer & Author
1) Limewater is basically Calcium carbonate, and when calcium carbonate experiences thermal decomposition, the products are Calcium oxide and Carbon dioxide.
2)A white solid will be formed and there will be effervescense because of the release of carbon dioxide.
Hi Winston,
I am glad you took action!
There is a saying: “80% of the Success is Just About Taking The Necessary Actions!”
I agree with you that the Products are:
Calcium oxide (CaO) and carbon dioxide (CO2).
Equation: CaCO3(s)->CaO(s) + CO2(g)
For the observations, white CaO solid will be formed. You are right.
But how come “effervescence”? Want to share with me your thoughts?
Hear from you.
PS: Other students reading this comment, do give your views.
Cheers
Sean Chua
Master Trainer & Author
WINNERS Education Group
Products:
Calcium oxide (CaO) and carbon dioxide (CO2).
Equation: CaCO3(s)->CaO(s) + CO2(g)
Observation: White solid forming, with effervescence which will extinguish a flame.
Calcium oxide (CaO) and carbon dioxide (CO2).
Equation: CaCO3(s)->CaO(s) + CO2(g)
Observation: White solid forming, with effervescence which will extinguish a flame.