Astudent performed the fractional crystallization experiment described with the following results: initial mass of sample mixture: 4.958 g, mass of salicylic acid recovered, 0.586 g; mass of cuso4•5h2o recovered, 3.12 g. what percentage of the original sample was recovered?

74.75%

Explanation:

To calculate this, we simply add the mass of the salicylic acid and the mass of the copper sulphate.

The addition will yield the following.

Mass of salicylic acid recovered = 0.586g

Mass of copper sulphate recovered = 3.12g

The addition of both is = 0.586g + 3.12g = 3.706g

The percentage composition can be calculated by dividing this by the original mass of the mixture before crystallization and dividing by 100.

3.706/4.958 * 100 = 74.75%

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

plasma - state of matter made up of electrically charged particles