Which statement is true of a chemical change?
A.
It involves changes in the molecular structure.
B.
It involves changes in phase but not changes in the molecular structure.
C.
It involves dissolving one substance into another.
D.
It involves a change in the state, or phase of a substance.
E. It involves the process of separating two or more dissolved substances.
Reset

A is the answer. Chemical changes happen when atomic bonds are broken or created during chemical reactions. Hence, in this case, it involve changes to molecular structure.

- Change in states are physical changes.

- When salts are dissolved in water, you can use Distillation to separate them. Distillation is a physical change as well.

- Dissolving is just physical change.

Explanation:

The statement that is true of a chemical change among the statements given in the question is "It involves changes in the molecular structure". The correct option among all the options that are given in the question is the first option or option "A". I hope the answer has actually come to your help.

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%