Number of atoms in 125 g of C2H22011

If you try to move a piano and are unable to move it, did you perform any work in the scientific sense of the word? yes? or no? this question is worth 20 points! let it be correct!

Give one example of a pure (exact) number and of an estimated (measured) number.

Which compound should undergo substitution of the bromine by phenolate anion? draw the structure of the organic product?