Answer:
Specific Rotation = 105º
S% in mixture = 92%
Explanation:
Specific rotation in organic compounds varies linearly, then the enantiomeric excess can be express as:

Where alpha is the specific rotation of the mixture and alpha pure is the specific rotation of the excess enantiomer.
Then, knowing that the S enantiomer is in excess you can calculate the specific rotation of that mixture:


For calculating the percentage of S you should remember that the enantiometric excess is the percentage of excess of a certain enantiomer, for example in this case:

Since S is in Excess
Also, it is true:

Then you can solve the system of linear equations, finding:

Hope it helps!
Answer: The atomic number
Just use q=mCDeltaT
q=energy
m=mass
c=specific heat
Delta T= Change in temperature
Bromine is a chemical element with the symbol Br and atomic number 35.