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A chemist prepares a solution of sodium bromide by measuring out of into a volumetric flask and filling to the mark with distilled water.Calculate the molarity of anions in the chemist's solution.Be sure your answer is rounded to significant digits.

User Fluidity
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Answer:

The molarity of the Br anion is 0.00136 M = 0.0014 M to 2 s.f

Step-by-step explanation:

Complete full question

A chemist prepares a solution of sodium bromide (NaBr) by measuring out 14. mg of NaBr into a 100 mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to 2 significant digits.

To do this, we first calculate the molarity of the aqueous solution of NaBr.

Molarity = (Concentration in g/L) ÷ (Molar Mass)

(Concentration in g/L)

= (Mass of solute in g) ÷ (Volume of solution in L)

Mass of solute = 14 mg = 0.014 g

Volume = 100 mL = 0.10 L

(Concentration in g/L)

= (Mass of solute in g) ÷ (Volume of solution in L)

(Concentration in g/L) = (0.014/0.1) = 0.14 g/L

Molarity = (Concentration in g/L) ÷ (Molar Mass)

Molar Mass = 102.894 g/mol

Molarity = (0.14/102.894) = 0.0013606236 M = 0.00136 M

Assuming complete dissociation, NaBr dissociates into

NaBr → Na⁺ + Br⁻

1 mole of NaBr gives 1 mole of Br⁻

0.00136 M of NaBr will give 0.00136 M of Br⁻

So, the molarity of the Br anion is 0.00136 M = 0.0014 M to 2 s.f

Hope this Helps!!!

User Pavot
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