Select the correct answer from each drop-down menu. Describe an oxidation-reduction reaction.

In an oxidation-reduction reaction, oxidation is what happens when a reactant___ . Reduction occurs when a reactant ___ in the reaction.

Explanation:

First off, we have to understand what we means by oxidation and reduction.

Oxidation is the loss of electrons during a reaction by a molecule, atom or ion. Oxidation occurs when the oxidation state of a molecule, atom or ion is increased.

Reduction on the other hand is the opposite of oxidation. It is the gain of electrons during a reaction by a molecule, atom or ion. Reduction occurs when the oxidation state of a molecule, atom or ion decreases.

Back to the question;

oxidation is what happens when a reactant loses electrons.

Reduction occurs when a reactant gains electrons in the reaction.

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%

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante