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One of the most common uses of gravimetric analysis is determining the concentration of an ion in a solution(i.e. to determine pollutants in a lake). If a sample of lake water turns out to have a concentration of (1.17x10^-2) M AgNO3 How many grams of NaCl are required to precipitate most of the Ag+ ions from (2.7x10^2) mL of the (1.17x10^-2) M AgNO3 solution? Assume the molar mass of NaCl is 58.45 g/mol.

User Lucatrv
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Answer: 0.0185 grams of NaCI.


Step-by-step explanation:

To determine the amount of NaCl required to precipitate most of the Ag+ ions from the given AgNO3 solution, we can use the following steps:

Determine the number of moles of Ag+ ions in the solution:

Molarity of AgNO3 solution = 1.17 x 10^-2 M

Volume of AgNO3 solution = 2.7 x 10^-2 L

Number of moles of Ag+ ions = Molarity x Volume

Number of moles of Ag+ ions = (1.17 x 10^-2) x (2.7 x 10^-2)

Number of moles of Ag+ ions = 3.159 x 10^-4 moles

Use the stoichiometry of the balanced chemical equation to determine the amount of NaCl required to precipitate most of the Ag+ ions:

AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)

From the balanced chemical equation, we can see that 1 mole of AgNO3 reacts with 1 mole of NaCl to produce 1 mole of AgCl.

Therefore, the number of moles of NaCl required to precipitate most of the Ag+ ions is also 3.159 x 10^-4 moles.

Convert the moles of NaCl to grams:

Molar mass of NaCl = 58.45 g/mol

Mass of NaCl = Number of moles of NaCl x Molar mass of NaCl

Mass of NaCl = (3.159 x 10^-4) x 58.45

Mass of NaCl = 0.0185 grams

Therefore, 0.0185 grams of NaCl are required to precipitate most of the Ag+ ions from 2.7 x 10^-2 L of the 1.17 x 10^-2 M AgNO3 solution.


Bear in mind that this is not a rocket science. But it was fun. I enjoy the process. Thank you for asking.

User JokerMartini
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