10)Calculate the molarity of a potassium dichromate solution prepared by placing 9.67 g of K Cro in a 2 2 7
100-ml volumetric flask, dissolving, and diluting to the calibration mark.​

0.33 M

Explanation:

From the question given above, the following data were obtained:

Mass of K₂Cr₂O₇ = 9.67 g

Volume of solution = 100 mL

Molarity =?

Next, we shall determine the number of mole in 9.67 g of K₂Cr₂O₇. This can be obtained as follow:

Molar mass of K₂Cr₂O₇ = (39×2) + (52×2) + (16×7)

= 78 + 104 + 112

= 294 g/mol

Mass of K₂Cr₂O₇ = 9.67 g

Mole of K₂Cr₂O₇ =?

Mole = mass /Molar mass

Mole of K₂Cr₂O₇ = 9.67 / 294

Mole of K₂Cr₂O₇ = 0.033 mole

Next, we shall convert 100 mL to litre (L). This can be obtained as follow:

1000 mL = 1 L

100 mL = 100 mL × 1 L / 1000 mL

100 mL = 0.1 L

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Mole of K₂Cr₂O₇ = 0.033 mole

Volume of solution = 0.1 L

Molarity =?

Molarity = mole / Volume

Molarity = 0.033 / 0.1

Molarity = 0.33 M

Thus, the molarity of the solution is 0.33 M

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.

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.