A chemistry student is given the task of analyzing the three unknown samples in the previous question. Compare the densities from Samples A, B, and C above to the accepted densities of the substances below. Identify the unknown samples as being either aluminum, iron, nickel, or tin. Densities of Common Elements Element Name Density (g/cm3) Aluminum 2.701 g/cm3 Iron 7.86 g/cm3 Nickel 8.90 g/cm3 Tin 7.28 g/cm3 Sample A Sample B Sample C

It’s B

Explanation:

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.

tracks, burrows, eggshells, nests, tooth marks, or gastroliths