One mole of anything contains 6.02 x 10^23 molecules. So there are how many moles P2O5 in 1.2 x 10^25 molecules? There are
1.2 x 10^25 molecules x (1 mol/6.02 x 10^23 molecules) = y moles P2O5.
Then moles oxygen atoms is;
mols oxygen atoms = y moles P2O5 x (5 oxygen atoms/1 mol P2O5) = ??
O in SO3 is done the same way.
how many moles of oxygen atoms does 1.2x10^25 diphosphorus pentoxide molecules have?
hwo many oxygen atoms are in 1.25 mol sulphur trioxide?
i don't understand these
5 answers
thanks
why is it 5 oxygen atoms over 1mol P2O5?
why is it 5 oxygen atoms over 1mol P2O5?
so the second one is
# O atoms = 1.25 mol SO3 x 1molSO3/6.02x10^23 molecules x 3molO/1molSO3 x 6.02x10^23atoms/1molO= 3.75 atomsm O?
# O atoms = 1.25 mol SO3 x 1molSO3/6.02x10^23 molecules x 3molO/1molSO3 x 6.02x10^23atoms/1molO= 3.75 atomsm O?
The 1.25 x 10^25/6.02 x 10^23 converts molecules P2O5 to mols P2O5. I obtained 20.76 but check that.
To find mols oxygen in P2O5, you see there are 5 oxygen atoms per 1 mol P2O5, therefore, there must be 5 x 20.76 mols of oxygen in 20.76 mols P2O5.
To find mols oxygen in P2O5, you see there are 5 oxygen atoms per 1 mol P2O5, therefore, there must be 5 x 20.76 mols of oxygen in 20.76 mols P2O5.
When I said the second one was worked the same way I meant the concept was the same but the algebra a different. Let's recapitulate the first one so you can see how the units cancel, then we will do the second one your way and see the units don't cancel so we know it isn't correct.
# mols O atoms in 1.25 x 10^25 P2O5 molecules = 1.25 x 10^25 moleculesP2O5 x (1 mol P2O5/6.02 x 10^23 molecules P2O5) x (5 mols O atoms/1 mol P2O5) = about 104 mols O atoms.
Note that the first term cancels molecules P2O5 in the numerator of 1.25 x 10^25 molecules P2O5 with the denominator of the first term--which converts to mols P2O5). Then the second term has 5 mols O atoms/1 mol P2O5 so the denominator of that term cancels 1 mol P2O5 with the numerator of the second term leaving mols O atoms which is what you want for the answer. I'm sure you must have looked at this way of doing most chemistry problems when you studied dimensional analysis. Now for the second term. You had
O atoms = 1.25 mol SO3 x 1molSO3/6.02x10^23 molecules x 3molO/1molSO3 x 6.02x10^23atoms/1molO= 3.75 atomsm O?
Write this out so you can see it. mol SO3 in numerator of term 2 cancels with denominator of term 3. 6.02 x 10^23 molecules in term 2 denominator cancels with numerator of term 4. Mols O in denominator of term 4 cancels with mols O of numerator of term 3. So you are left with mols SO3 x 3 = 3.75 mols O BUT that isn't the question. The question is for the NUMBER of oxygen atoms (not mols) in 1.25 mols SO3. Here is what you do.
1.25 mols SO3 x (6.02 x 10^23 molecules SO3/1 mol SO3) x (3 atoms O/1 molecule SO3) = ?? molecules O atoms. Note that mols SO3 cancels with mols SO3 and molecules SO3 cancels with molecules SO3 to leave in the numerator atoms Oxygen.
# mols O atoms in 1.25 x 10^25 P2O5 molecules = 1.25 x 10^25 moleculesP2O5 x (1 mol P2O5/6.02 x 10^23 molecules P2O5) x (5 mols O atoms/1 mol P2O5) = about 104 mols O atoms.
Note that the first term cancels molecules P2O5 in the numerator of 1.25 x 10^25 molecules P2O5 with the denominator of the first term--which converts to mols P2O5). Then the second term has 5 mols O atoms/1 mol P2O5 so the denominator of that term cancels 1 mol P2O5 with the numerator of the second term leaving mols O atoms which is what you want for the answer. I'm sure you must have looked at this way of doing most chemistry problems when you studied dimensional analysis. Now for the second term. You had
O atoms = 1.25 mol SO3 x 1molSO3/6.02x10^23 molecules x 3molO/1molSO3 x 6.02x10^23atoms/1molO= 3.75 atomsm O?
Write this out so you can see it. mol SO3 in numerator of term 2 cancels with denominator of term 3. 6.02 x 10^23 molecules in term 2 denominator cancels with numerator of term 4. Mols O in denominator of term 4 cancels with mols O of numerator of term 3. So you are left with mols SO3 x 3 = 3.75 mols O BUT that isn't the question. The question is for the NUMBER of oxygen atoms (not mols) in 1.25 mols SO3. Here is what you do.
1.25 mols SO3 x (6.02 x 10^23 molecules SO3/1 mol SO3) x (3 atoms O/1 molecule SO3) = ?? molecules O atoms. Note that mols SO3 cancels with mols SO3 and molecules SO3 cancels with molecules SO3 to leave in the numerator atoms Oxygen.
2 answers