alright... the problem is:

 

What is the mass of 1.0 millimole of sulfur dioxide?

 

I am aware that one mole = 1000 millimoles, but I can't figure out how to work this one out. What is the answer, and how did you reach it?

 

thanks

well I`m not sure if this belongs in maths as the math guys may not know chem enough to know this.

 

basicly sulpher dioxide is SO2, meaning 1 part Sulpher and 2 parts Oxygen, then you look up the Atomic mass of these elements, that will tell you how many grams are in 1 mole of each, so apply that using your PTOE, add them together and then divide by 1000, and that will be your answer in grams (or milligrams in this case)

What's the mass of one molecule? How many molecules are in a millimole?

Molar Mass of SO2=32g+2*16g=64g/Mole

You dont need to know how many molecules per mole. You already have the answer in terms of moles, now just do simple unit analysis and conversion to convert moles to millimoles and you have the answer.

 

LF