What is the iupac name of a bromobenzene with carboxylic acid attached

Bromobenzoic acid  

Explanation:

COOH has higher priority than Br, so the parent name is benzoic acid.

The COOH group is automatically on C1 of the ring, and the other aromatic carbons are numbered sequentially around the ring.

The name of the substituent is joined to that of the parent, and the locant is attached to that with a hyphen.

The generic IUPAC name is bromobenzoic acid.

There are three isomers of benzoic acid — 2-bromobenzoic acid, 3-bromobenzoic acid, and 4-bromobenzoic acid —  so you must always specify which one you mean.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%