[johniie77]

1) I have a compound x that has an observed rotation of +15. its a .1M solution and its molecular weight is 125g/mol(length is 1 dm).
I calculated the specific rotation of it, however the two questions that are stumping me are "what is the observed rotation if the original solution is diluted with an equal volume of solvent" and "what is the observed rotation of a solution that contains .01 mole of compound x and .005 mole of another compound y which is an enantiomer of compound x?"

For the first one i was told it was 7.5 however I am not sure how they arrived at that. and for the second one im not sure how to approach it.

[sjb]

1) I have a compound x that has an observed rotation of +15. its a .1M solution and its molecular weight is 125g/mol(length is 1 dm).
I calculated the specific rotation of it, however the two questions that are stumping me are "what is the observed rotation if the original solution is diluted with an equal volume of solvent" and "what is the observed rotation of a solution that contains .01 mole of compound x and .005 mole of another compound y which is an enantiomer of compound x?"

For the first one i was told it was 7.5 however I am not sure how they arrived at that. and for the second one im not sure how to approach it.

How does observed rotation relate to concentration?

I think you will need concentrations (or equivalent) to do the second part, after all, you can see from the first part rotation varies with concentration as well as composition.