A chemist places 1.4142 g of Na 2 SO 4 in a 100 mL volumetric flask and adds wat

Question

A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist places 1.4142 g of Na2SO4 in a 100 mL volumetric flask and adds water to the mark. She then pipets 20 mL of the resulting solution into a 50 mL volumetric flask and adds water to the mark and mixes to make a solution. She then pipets 15 mL of this new solution into a 25 mL volumetric flask and dilutes to the mark. Determine the molar concentration of sodium sulfate in the most dilute solution prepared. Report your answer using the correct number of sig figs. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.               A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution. A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI2. He pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. He then pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. He analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000617 M. (Note: in solution, calcium iodide breaks apart into one Ca2+ ion for every two I- ions, so a solution that is 1.0 M in CaI2 is 2.0 M in I-.) Determine the molar concentration of calcium iodide in the original solution.

Explanation / Answer

1)initial number of moles of sodium sulphate=1.4142/142

=0.01 moles

so the initial concentration=0.01*1000/100

=0.1

now the new concentration=0.1*20/50

=0.04 M

again after diluting, concentration=0.04*15/25

=0.024 M

so the answer is 0.024 M

2)concentration of the Ca2+ion=0.00000617/2

=0.000003085 M

so let the initial concentration be x.so,

x*(25/100)*(10/25)=0.000003085

or x=3.085*10^-5 M

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