Question

PLEASE HELP LAB QUESTION DUE TOMORROW!! A substance has a mass of 90.1 grams and contains 3.0 x 10^23 molecules. Which of the 3 substances in the chart above is it? (Solve for moles first using the molecules given, then set up a ratio to find g in 1 mole.)

Answer 1

When I solved for moles I got 5.0 moles. I do not know if this is correct and where to go from there??

Answer 2

This is the chart they are referring to.

Answer 3

its 0.5 and not 5.0..

Answer 4

since no of moles=given no. of molecules / 6.023*10^23

Answer 5

we know no.of moles=given wt/molecular wt..
here the given wt is 90.1g and the no of moles is 0.5 (approx).
plug in these two values in the equation to find the molecular weight

Answer 6

Now compare this molecular mass with the 3 molecular masses in the table...
any mass really close to what u got..?! then that is the correct substance.