Calculate the concentration of the cobalt(II) chloride hexahydrate solution titrated in the fine titration experiment. Show your calculations and provide answer with the appropriate number of significant figures.
concentration of AgNO3 solution (mol/L)
0.125
volume of sodium chloride solution (mL)
30.00
volume of AgNO3 dispensed (mL)
24.35
To calculate the concentration of the cobalt(II) chloride hexahydrate solution, we need to use the concept of stoichiometry and the balanced chemical equation of the reaction that took place in the fine titration experiment.
Given:
Concentration of AgNO3 solution (mol/L) = 0.125 M
Volume of sodium chloride solution (mL) = 30.00 mL
Volume of AgNO3 dispensed (mL) = 24.35 mL
The balanced chemical equation for the reaction involving cobalt(II) chloride hexahydrate (CoCl2·6H2O) and silver nitrate (AgNO3) is:
CoCl2·6H2O + 2AgNO3 -> Co(NO3)2 + 2AgCl + 6H2O
From the balanced equation, we can see that 1 mole of cobalt(II) chloride hexahydrate (CoCl2·6H2O) reacts with 2 moles of silver nitrate (AgNO3).
To find the moles of AgNO3 used, we can use the formula:
moles = concentration (mol/L) * volume (L)
Firstly, we need to convert the volume of silver nitrate solution to liters:
volume of AgNO3 dispensed (L) = 24.35 mL * (1 L / 1000 mL) = 0.02435 L
Then we can calculate the moles of AgNO3:
moles of AgNO3 = 0.125 M * 0.02435 L = 0.00304375 moles
Since 1 mole of cobalt(II) chloride hexahydrate (CoCl2·6H2O) reacts with 2 moles of AgNO3, the moles of cobalt(II) chloride hexahydrate (CoCl2·6H2O) present in the solution is half the moles of AgNO3 used:
moles of CoCl2·6H2O = 0.00304375 moles / 2 = 0.001521875 moles
Now we need to convert the moles of cobalt(II) chloride hexahydrate (CoCl2·6H2O) to concentration using the formula:
concentration (mol/L) = moles / volume (L)
We are given the volume of sodium chloride solution in milliliters, so we need to convert it to liters:
volume of sodium chloride solution (L) = 30.00 mL * (1 L / 1000 mL) = 0.03000 L
Finally, we can calculate the concentration of the cobalt(II) chloride hexahydrate (CoCl2·6H2O) solution:
concentration (mol/L) = 0.001521875 moles / 0.03000 L = 0.050729 mol/L
Rounding off the answer to the appropriate number of significant figures, the concentration of the cobalt(II) chloride hexahydrate solution is 0.0507 mol/L.