Here is an common question on Mole Calculations. More specifically it involves skills in balancing chemical equations and writing ionic equations.
PS: Try it out and leave your suggested answer at the “Comments Section” right below this post.
Question:
Lead carbonate reacts with nitric acid to form 3 other products.
a) Identify the 3 products formed and write a balanced chemical equation.
b) Identify the spectator ions and then write the ionic equation.
Your a good teacher better than our chemistry teacher LOL!!!!!!
Note- tip
Chemistry is about understanding
Without understanding comes no knowledge
Hope this helps
GOD BLESS!!!!!
yes something is wrong :(:(:(:(:(
Hi Sarah,
In view that 1 molecule of ammonia contains 3 hydrogen atoms, i believe your working is correct!
Keep Learning,
Sean Chua
Master Trainer & Author
Hi Saud,
Something not right with your Chemical Formulae of Lead (II) Nitrate.
As such, your balanced chemical equation and ionic equation is incorrect.
Regards,
Sean Chua
hello sir,
i have a simple chemistry question which i have solved but i am not quite sure of the answer:
Q: how many atoms of hydrogen are there in 0.75 moles of ammonia?
Ans:
no. of molecules of ammonia = 0.75*6.02*10^23
no of atoms of hydrogen = 3*0.75*6.02*10^23
=1.35*10^24
is it correct?
Hi Kendrik,
im not a teacher but still i guess i can tell you about it…………
when we say about 1 mole of a substance, we mean to mention its 6.02 X 10 power 23 particles of it………………….
so for one atom i-e one particle of it first we should find its moles by dividing 1 by the avogadro’s number i-e 6.02 X 10 power 23………….
then by simple formula of moles= mass/molar mass
mass= molar mass X moles
we know the molar mass of calcium = 40
and (calculated) moles of one atom of calcium = 1.661129568106312292358803986711 power negative 24
then by multiplying 40 by the mole number
40 X 1.661129568106312292358803986711 = 6.6445182724252491694352159468439 power negative 23 grams…… 🙂
hope you did not felt humiliated 🙂 🙂 🙂
being a carbonate CO2 is sure, others are Lead Nitrate and water
as for the balanced equation:-
PbCO3(s) + HNO3(aq) ——> PbNO3(aq) + CO2(g) + H2O(l)
for the spectator ions:-
NO3 (-1) aq
the equation would be
PbCO3(s) + H (+1)(aq) —–> Pb (+2)(aq) + CO2(g) + H2O(l) 🙂
Hi Sir,
I have attempted a few mole calculation questions and I am stuck with one question.
The question simply ask me to calculate:
the mass of one calcium atom
I am unsure how to do it. Can you please guide me?
Thank you very much =)
this is so useful. i dont get a thing in class! sigh!
send me O level calculations of mole and electrolysis please.
Hi Jo,
Glad you tried the question. There is a saying ?Wanting leads to Wanting, Doing leads to Having?.
Part (a) – correct state symbols, and stoichiometry for the balanced chemical equations. Well done!
Part (b) – Ionic Equations is correct. However, the answer for Spectator Ions is not fully correct.
Spectator Ions are defined as ions that does not take place in the chemical reactions. They are there just to stabilize the reaction.
In this case, only NO3-(aq) ions is Spectator Ions. Meaning the other 2 ions you have mentioned, H+(aq) and Pb2+(aq) are involved in the chemical reaction, and not Spectator Ions.
PS Reply: Only compounds made from metals of the Transition Block have roman symbols in their chemical name. This is because they have variable oxidation states.
Cheers
Sean
Hi Karissa,
Refer to my previous post on Table of Solubility of Salts.
http://simplechemconcepts.com/chemistry-question-solubility-of-common-salts/
For GCE O Level N Level, IB Program and ICGSE, there are 2 cations in your syllabus that will form insoluble salts with chlorides.
There are Ag+ and Pb2+, to form insoluble AgCl (s) and PbCl2 (s) respectively.
Hope this helps. Let me know if you understand it.
Cheers
Sean =)
Which cation can make an insoluble product with Cl? in water?
Hi Jo,
Glad you tried the question. There is a saying “Wanting leads to Wanting, Doing leads to Having”.
Part (a) – correct state symbols, and stoichiometry for the balanced chemical equations. Well done!
Part (b) – Ionic Equations is correct. However, the answer for Spectator Ions is not fully correct.
Spectator Ions are defined as ions that does not take place in the chemical reactions. They are there just to stabilize the reaction.
In this case, only NO3-(aq) ions is Spectator Ions. Meaning the other 2 ions you have mentioned, H+(aq) and Pb2+(aq) are involved in the chemical reaction, and not Spectator Ions.
PS Reply: Only compounds made from metals of the Transition Block have roman symbols in their chemical name. This is because they have variable oxidation states.
Cheers
Sean
Hi.
a) carbon dioxide, lead(II) nitrate and water.
PbCO3(s) + 2HNO3(aq) –> H2O(l) + CO2(g) + Pb(NO3)2(aq)
b) spectator ions: 2H+, 2NO3-, Pb2+
PbCO3(s) + 2H+(aq) –> H2O(l) + CO2(g) + Pb2+(aq)
PS: could you tell me which metals normally have different roman symbols in front of them? I have noticed that metals like copper have a roman symbol in front, in the case of copper(II) sulphate.
Thank you very much.