## Grams to Mol

J_Rodriguez_Dis2k
Posts: 25
Joined: Fri Sep 25, 2015 3:00 am

### Grams to Mol

I have trouble understanding where do I get the grams when I am converting grams to mol.

Chiara R 1K
Posts: 22
Joined: Fri Sep 25, 2015 3:00 am

### Re: Grams to Mol

I think when you are doing a conversion, the grams are from the molar mass (g/mol) of the element/molecule/compound, and to find the molar mass you add the atomic mass of each unit within the molecule/compound. So, for example, the molar mass of water (H2O) is 18.02 g/mol (1.01 g H + 1.01 g H + 16 g O), and so 1 mol water=18.02 g water. Then you can use this for any conversions.

Mariam Ghattas 2L
Posts: 14
Joined: Fri Sep 25, 2015 3:00 am

### Re: Grams to Mol

So a mole is just a way of measuring an element so 1 mole of anything is simply 6.022*10^23 atoms of that particular something.
You have to keep in mind that some atoms are heavier/lighter than others, for example hydrogen atom with only 1 proton in its atomic weight will be very small in comparison to carbon that has 6 protons and average 6 neutrons.
So a mole of hydrogen will be lighter than a mole of Carbon
In order to find the amount of grams for each element for each mole, you have to use the atomic weight since the nucleus is the heaviest part of the atom. Electrons mass is very small in comparison to neutrons and protons therefore it is not used .

One example will be 1 mole of carbon is equal to 12.01 grams
1 mole of potassium is equal to 39.10 grams

You can use these values or basically any atomic weight in converting from grams to moles
Example if we are given a sample of nitrogen that weights 28.02 grams and we are asked how many moles are in the sample
First we have to look in the periodic table and find the amount of grams per mole for that specific element. In this case, Nitrogen atomic mass is 14.01 grams / moles
so we take the value of our sample 28.02 grams and multiply that with (1 mole/14.01 grams of nitrogen ) =2 moles.
All your units must cancel till you reach the desired unit , in our example it is moles. So we had to do something to make the grams cancel out
I hope that helped you understand how to convert from grams to moles

004594950
Posts: 28
Joined: Fri Sep 25, 2015 3:00 am

### Re: Grams to Mol

704442519 wrote:I have trouble understanding where do I get the grams when I am converting grams to mol.

the grams is the molar mass of a compound. to find it, you use the periodic table and look at the mass of each element and add it together. if a compound has a subscript or a coefficient, you need to multiply the mass of that element or chomped by the number.