Halo Students,
Chemistry Practical is round the corner and Chemistry Paper 2 in less than 3 week time.
Hope your preparation is going well.
Since this is the weekend, i think you might want some more conceptual chemistry questions to think it through. Here is the start of more to share:
Question:
Calcium Carbonate decomposes more readily on heating than sodium carbonate. Suggest a reason for this.CaCO3 –> CaO + CO2
Na2CO3 –> Na2O + CO2
Think about it.
PS: Leave your suggested answers in the “Comments” section below.
Rgds
Sean
I think the key-phrase is ‘thermally (un)stable’
PSCMACZITLHCMSG is a method to memorise the reactivity series of metals.
Potassium, Sodium, Calcium, Magnesium, Aluminium, (Carbon), Zinc, Iron, Tin, Lead, (Hydrogen), Copper, Mercury, Silver, Gold
It can be remembered as:
Please Stop Calling Me A Cow, ZIT, Low High Cholesterol, MSG
I would also like to ask if it is sufficient for us to memorise the following for the reactivity series:
Potassium, Sodium, Calcium, Magnesium, Zinc, Iron, Lead, (Hydrogen), Copper, Silver
Sodium is a more reactive metal than calcium, therefore sodium carbonate will be more thermally stable as compared to calcium carbonate. Therefore, Calcium Carbonate decomposes more readily on heating than sodium carbonate.
P
S
C
M
A
C
Z
I
T
L
H
C
M
S
G
=D
cool.
observing the reactivity series of the metals…………….Ca is below Na …………..this depicts that calcium is relatively less reactive than sodium. this means that calcium “less” prefers to be in forms of ions than sodium. this is said as sodium carbonate is more to heat than Calcium carbonate therefore CaCO3 decomposes better than Na2CO3. 🙂
Hi Okpewho,
Chlorine water is used as an disinfectant for municipal water for developed and developing countries. Chlorine can be applied for the deactivation of most microorganisms and it is relatively cheap.
Hope this information helps.
To Your Academic Success in Chemistry,
Sean Chua =)
Hi Waleed Bin Qasim,
Yes. Your thought on this question is spot on. Very good analogy using magnet also.
Keep up your good work.
To Your Academic Success in Chemistry,
Sean Chua
K
Na higher in reactivity series. very reactive but also forms a very stable compound. like a stronger magnet forms a stronger attraction.
Ca. hence below in the reactivity series less reactive as compared.and forms less stable or strong bond as compared.
Mg
.
.
C
sir do comment. waiting.
why is chlorine used in water treatment
Hello FluffySnow,
Do note that the correct chemical formula for calcium carbonate is CaCO3, which are formed by the Cation Ca2+ and Anion CO32-.
Back to the question on the stability of the carbonates from decomposition due to heating.
You need to understand the Metals & Its Reactivity Series.
Na metal is more reactive than Ca metal. As such, Na would love to react more readily with any substance, as compared to Ca.
The compound that is formed by Na will be more stable now..ie, the electrostatic attraction btw the Na+ & CO32- in the compound is much stronger.
The compound that is formed by Ca will be less stable (as compared to Na compound), i.e. the eletrostatic attraction btw the Ca2+ & CO32- in the compound is less strong.
As such, CaCO3 is more easily to decompose by heat, as compared to Na2CO3.
Hope this explanation helps.
Cheers
Sean =)
As such,
hmm. IMO, shouldn’t Calcium carbonate be more stable than sodium carbonate?
Calcium carbonate is infact Ca2(CO3)2, which means that the electrostatic forces between the calcium and carbonate ion should be stronger as compared to Sodium carbonate, which only has 2 sodium ions forming bonds with a single carbonate ion.
So, shouldn’t calcium carbonate, with 2 calcium ions attached to 2 carbonate ions, be more stable?
Halo Zhengning, Lijun and Anonymous.
Well Done. In fact all three of you got the concepts spot-on and i thought your answers are GOOD.
“Na is more reactive than Ca, and thus forms a much stable compound with Carbonate. It is like Na is so reactive that they “hold” carbonate so tightly and strongly that they requie higher heat energy to break the ionic bondig”-informal annswer for understanding.
Rgds,
Sean
SimpleChemConcepts
“Learning Experience with A Difference”
Sodium is higher than calcium in the reactivity series, thus making it more reactive and forming more stable compounds. Thus calcium carbonate decomposes more readily than sodium carbonate.
I hope I’m right. :\
actually, i do somewhat understand this, but i can never get it penned down in words. =/
all i know is that,
since sodium is more reactive than calcium, it will form a more stable carbonate than calcium. hence, sodium carbonate will not decompose as easily as calcium carbonate.
can u please explain this in greater detail? thanks.
I would like to give this a try, not sure of the correct answer however.
Hmmm is it because Na is a more reactive metal as compared to Ca? The more stable the compound, the higher the temperature is needed for decomposition. Hence, Na2CO3 will takes a longer time…
I think? hahaha.