Methyl orange and phenolpthalein are common chemical indicators often used in titrations. what is the role of a chemical indicator?

Explanation:

Chemical indicators:-

They are species or the substances which are added to the reaction mixture. They undergoes a specific and distinct observable change in the reaction mixture indicating  the formation of consumption of the species in the reaction mixture. The change can be a color change, olfactory change, etc.

Example:-

Methyl yellow which imparts yellow colour to the alkaline solutions and is red in acidic solutions.

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%