001 nm!) One of the important functions of the spectrometer is to provide \"narr
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001 nm!) One of the important functions of the spectrometer is to provide "narrowband" light- that is, light for which the spread of wavelengths is small. Apparent deviations from the Beer- Lambert law are often due to insufficiently monochromatic light A note on aqueous nickel solutions1 The absorbing species in this experiment is the aqueous nickel complex, Ni(H20 Since this complex contains both proton acceptors and proton donors, it can act as an acid or as a base, depending on the pH. In sufficiently alkaline conditions, protons are removed from the complex, resulting in nickel hydroxide complexes that are water-insoluble. This reduces the true concentration of nickel below that you would expect based on the mass of solute dissolved. Therefore, to have a reproducible result it is necessary to keep your sample solution acidic. We do that by adding a small amount of HCI(aq). You will be given a stock solution of 175 mM Ni(NO3)2(aq) in the lab. (This solution is ntensely green. Don't confuse it with the less intensely colored 75 mM Ni(NO)2(aq) that is also in he lab.) You will use volumetric flasks and a buret to make a series of aqueous solutions with olarities 15, 35, 75, 100, 125, 150, and 175 mM. Make a table in your notebook estimating the olume of the stock solution you need to put into each 10-mLvolumetric flaskExplanation / Answer
Preparation of solutions starting with 175 mM Ni(NO3)2 stock solution
final volume of solution = 10 ml
Solution (M) Volume of stock (ml) taken
15 15 mM x 10 ml/175 mM = 0.86 ml
35 35 mM x 10 ml/175 mM = 2.0 ml
75 75 mM x 10 ml/175 mM = 4.3 ml
100 100 mM x 10 ml/175 mM = 5.7 ml
125 125 mM x 10 ml/175 mM = 7.1 ml
150 150 mM x 10 ml/175 mM = 8.6 ml
175 175 mM x 10 ml/175 mM = 10.0 ml
The balance in 10 ml would be water.
volume of water to be added = 10 ml - volume of stock added
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