A Chemistry Question that was posed by a local singapore student that is taking her O level this year.
Question:
Which of the following consists of the greatest number of atoms?
A. 4g of hydrogen gas, H2
B. 48g of solid magnesium, Mg
C. 71g of chlorine has, Cl2
D. 24 dm3 of argon gas, Ar at r.t.p.
Any takers??
PS: Leave your suggested answers in the “Comments” section below:
Rgds
Sean
Good. I’m glad a simple blog post like this is generating alot of you (Chemistry students) to think about solving it.
Answer is indeed A!
Keep learning. Feel free to share this blog with your friends.
Cheers!
Sean
the answer is a . the formulae of finding the no of particles is no of mole into 6.23 *10^23 . formulae of butane is c4h10. soo 25/(12*4+10)* 6.23 *10^23=3*10^23.
A is the answer
the answer for all is the same
the no. of atoms in each case is equal
Hi Sherman,
That is a good question from you. You are not wrong to signal out that molecules and ions are indeed different from atoms.
However, based on GCE O Level examination context, molecules and ionic compounds are essentially made up of atoms. As such, the questions is asking how many atoms made up a certain amount of molecules or ionic compounds.
As such, the answer still stands.
Hope this helps.
PS: By the way, which country are you from and which educational system/code do you follow?
Cheers
Sean Chua
Founder & Master Trainer of SimpleChemConcepts.com
Well Done!
Cheney answers is closest for his explaination.
This is indeed have to do with Avogadro’s constant.
Trick for this question is to pick up the fact that they are asking for ATOMS. H2 gas molecule has two atoms.
Sean
SimpleChemConcepts
“Learning Experience with A Difference”
A or B.
I worked out for A and B and I got 2 moles.
For C and D it is out because I got 1 mole.
I’m not too sure…
hmm. i think it’s A too.
not really sure, but since the avogadro constant states that ‘1 mol = amount of substance which contains 6.02 x 10^23 particles, where particles may refer to atoms, molecules, charges, ions or electrons’, then 2 mol of hydrogen gas probably contains 6.02 x 10^23 x 2 x 2 atoms, which magnesium only contains 6.02 x 10^23 x 2. This is because hydrogen is diatomic. or something like that. roughly la : )
I’m thinking it’s A…
No. of moles of H2 = 4/2 = 2 mol
No. of moles of Mg = 48/24 = 2 mol
No. of moles of Cl2 = 71/71 = 1 mol
No. of moles of Ar = 24/24 = 1 mol
We can rule out C and D, which leaves A and B – H2 obviously has more atoms than Mg, which leaves us with A ;D not very sure about this…