Show calculations and briefly describe how you will make the following solutions

Question

Show calculations and briefly describe how you will make the following solutions: a. 50.00 mL of 0.200M Fe(N0_3)_3(aq) solution from iron (III) nitrate nonhydrate. b. 200.00 mL of a 2.00mM KSCN_(aq) solution from potassium thiocyanate. c. 100.00 mL of 1.00M CoCI_2(aq) solution from Cobalt (II) chloride hexahydrate. Write the equilibrium expression for ionics equations used in and B of the lab based on the Net Ionic Equations that are shown in the prior section. Look at the expression for the cobalt complexation with chloride ions (of lab). How would doubling the amount of water in the reaction vessel affect the product concentrations compared to the reactant concentrations? How is the [] used in metal complexes like the Cobalt tetra chloride complex [CoCU]^2- different than the [] used in the general equilibrium expression that follows?

Explanation / Answer

1.a)

•            The molar mass of Fe(NO3)3 = 193.86g/mol

•            Volume of solution required, in liters = 50ml = 0.05L

•            Molarity of solution required = 0.20 M.

•            Calculate grams of solute (gs) required using equation

             gs = MMs x M x V

                = 193.86g/mol x 0.20M x 0.05L

                   = 1.94g

Dissolve 1.94 g of Fe (NO3)3 in 50 mL of distilled water.

b)

•            The molar mass of KSCN= 97.18g/mol

•            Volume of solution required, in liters = 200ml = 0.2L

•            Molarity of solution required = 2mM =2mM/1000 = 0.002M

•            Calculate grams of solute (gs) required using equation

             gs = MMs x M x V

                = 97.18g/mol x 0.002M x 0.2L

                  = 0.0388g

Dissolve 0.0388 g (38.8mg) of KSCN in 200mL of distilled water.

c) •        The molar mass of CoCl2.6H2O = 273.38g/mol

•            Volume of solution required, in liters = 100ml = 0.1L

•            Molarity of solution required = 1M

•            Calculate grams of solute (gs) required using equation

             gs = MMs x M x V

                = 273.38g/mol x 1M x 0.1L

                   = 27.338g

Dissolve 27.338g of CoCl3.6H2O in 100mL of distilled water.

2.

Fe3+ + SCN-   <-----> [FeSCN]2+

Equilibrium is established among these species of ions. Since + Fe3+ is yellow, SCN- is colorless, and the [FeSCN]2+ is a very deep blood red, we would notice changes in color if changes in the concentration of the red [FeSCN]2+ ion.

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