what is the difference between RAM and RFM in C2 chemistry?

  • -1 votes

Just need to know this along with how to calcu;ate molar mass, and the mass a subsatance with given examples, this is all C2 GCSE

Posted Sat 1st December, 2012 @ 22:04 by Eamon Walker

5 Answers

  • 1 vote

RFM = relative formul mass - is the mass of a compound or molecule (CO2 = 12+16+16)
RAM = relative atomic mass - is the mass of a single atom of an element (Na = 23)

for example sodium (Na) has a of RAM of 23. This is because it has 11 protons and 12 neutrons and when added together equal 23.

An example for RFM is carbon dioxide. it has the formula CO2. This means it is made up of 1 carbon atom and 2 oxygen atoms. to work out its RFM all you need to do is add up the idividual RAM's which would be 12 + 16 + 16   you can find out the RAM values for elements in the periodic table

Oxygens RAM = 16

carbons Ram = 12 

 hope this was helpful

Answered Sun 2nd December, 2012 @ 22:33 by stewart murphy
  • 1 vote

another point at which you can use this knowledge to work out mole is

moles = mass of element of compound(grams) divided by its RAM or RFM 

you use RAM if you are working out the moles of an element and RFM if you are working the moles for a compound 

moles = mass/RAM or RFM

you can rearrange this to find out the values of either mass or moles or ram/rfm depending on what information you have been given.

Answered Sun 2nd December, 2012 @ 22:38 by stewart murphy
  • 0 votes

will be grateful for answers, but I would like the answerers to be absolutely certain as I do not want to get something in my head and it turns out partly wrong plz :D

Answered Sat 1st December, 2012 @ 22:07 by Eamon Walker
  • 0 votes

thank you, that was enlightening indeed, I always get confused with RAM and RFM, would you mind giving an example for the second one just to rienforce it please.

Answered Mon 3rd December, 2012 @ 10:34 by Eamon Walker
  • 0 votes


for example if you had a question that said that you are given 22 grams of sodium
work out how many mole this is

we know that moles = mass/RAM
so we can look up from the periodic table that the RAM of sodium is 11 and we know from the question that we have 22 grams

so moles of Na = 22/11
= 2moles of sodium  

Answered Mon 3rd December, 2012 @ 20:33 by stewart murphy