How many moles are in 28.02 g of nitrogen?

Question

apoorvk · Answer

Hmm, the molar mass of Nitrogen atom is about 14g/mol.

So, whaddya think now?

anonymous · Answer

So would I divide 28.02 by 14 to get the mole number of about 2.001?

anonymous · Answer

@apoorvk

apoorvk · Answer

Yup. Right. Correct-o!

anonymous · Answer

Thank you so much! =) Do you happen to know the molar mass of water?

apoorvk · Answer

Hmm. You can find it out can't you?

Water is H2O - that is two molecules of Hydrogen and one molecule of Oxygen.

So the molar mass of H2O would be sum of twice the molar mass of each hydrogen atom and one oxygen atom.

Helps?

anonymous · Answer

So It would be 4+1? Im sorry, I didnt have the chance to learn this material and I am trying to complete a practice for my chem final

anonymous · Answer

@apoorvk

apoorvk · Answer

Oh well, no problem. Let's just clear things up a bit. :)

I guess you look up the periodic table and mug up the molar masses of first 18 or 20 elements that really helps.

But in any case, remember that molar mass of each hydrogen atom is 1g/mol and that of each oxygen atom is 16g/mol.

Now can you add as required?

anonymous · Answer

Thank you sooo much! =) That makes sense, so it would be 18?

apoorvk · Answer

yes, correct!!!! Good job! :)

apoorvk · Answer

As for the molar masses, you don't have to remember the exact decimal values, just remember the rounded of whole no. values.
(I know, mugging up sucks though :P)
In fact, let me post the essential ones here itself:

H - Hydrogen - 1
He - Helium - 4
C - Carbon - 12
N - Nitrogen - 14
O - Oxygen - 18
Na - Sodium - 23
S -Sulfur - 32
Cl- Chlorine - 35.5
K - Potassium - 39

vincent-lyon.fr · Answer

Moles of what? 

There are 2 moles of nitrogen atoms.
There is 1 mole of nitrogen molecules.

btaylor · Answer

Vincent-Lyon.Fr is right. There are 2 moles of nitrogen atoms, but nitrogen is diatomic, so there would be 1 mol of N2 molecules.

aravindg · Answer

@apoorvk molar mass of oxygen is 16 nt 18 :P

apoorvk · Answer

@aravindG - sorry typo! '16' is the molar mass of oxygen.
As for the nitrogen thingy, yeah you folks are right, but since nothing was mentioned, we would assume Nitrogen atoms right? No mention of nitrogen 'gas' or anything as such was present.