Asample of iron has a volume of 10.0 ml. the density of iron is 7.87 g/ml. which is the correct expression to calculate the mass of the sample using dimensional analysis?
10.0 ml ã (7.87 ml/1 g)10.0 ml ã (1 ml/7.87 g)10.0 ml ã (1 g/7.87 ml)10.0 ml ã (7.87 g/1 ml)

Explanation:

The dimensional analysis permits you to deduct the correct between the variables that are in direct or inverse relation by looking at the dimensions of each variable and how they can be combined into an equation to yield the desired dimensions (units).

In this case, you have the following quantities with their units:

Hence, you can state:

⇒ x = 10 mL × 7.87 g/mL = 10 mL × 7.87 g/ 1 mL

That is the last option.

it had to transfer to a care and maintenance mode

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.