Chemistry, 03.03.2020 04:23 eve2055

A student dissolves 14.g of benzoic acid C7H6O2 in 425.mL of a solvent with a density of 0.92 g/mL. The student notices that the volume of the solvent does not change when the benzoic acid dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.

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Answer from: sandy461

Molarity of the solution is 0.26 M and molality of the solution is 0.28 m

Explanation:

Molar mass of benzoic acid = 122.12 g/mol

So, 14. g of benzoic acid = $\frac{14.}{122.12}mol$ of benzoic acid = 0.11 mol of benzoic acid

We know, density is the ratio of mass to volume

So, mass of 425. mL of solvent = $(425.\times 0.92)g=391 g$

Molarity is defined as number of moles of solute dissolved in 1000 mL of solution

Here solute is benzoic acid and total volume of solution is 425. mL

So, molarity of solution = $\frac{0.11}{425.}\times 1000M=0.26M$

Molality is defined as number of moles of solute dissolved in 1000 g of solvent

So, molality of solution = $\frac{0.11}{391}\times 1000m=0.28m$

Answer from: Quest

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( $n_2$ ) .

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.

Answer from: Quest

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be

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A student dissolves 14.g of benzoic acid C7H6O2 in 425.mL of a solvent with a density of 0.92 g/mL....

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