Question

I. Copper solutions are often blue in col absorbed by these solutions? 2. Is blue light absorbed strongly by these solutions? Is red light? Explain your answers. 3. If you had a 0.10 M solution of CuSO, and a 0.50 M solution of CusO, (they are both blue solutions) how would they look different? In what way would they look similar? 4. If you have a 0.060 M CuSO4 stock solution, how do you make 20. mL of a 0.010 M CuSO solution? How many mL of 0.060 M CuSO, solution will you need to make 20. mL of 0.010 M CuSO solution? Show your calculations clearly.

Answer 1

Copper solutions are blue in color Color of right absorbed by these solution = Red If a particular color is absorbed by a solution (from white light), our eyes detect its complementary color (by mixing of all the other wavelength of white light) Red light is strongly absorbed by these solution same explanation as above A solution having higher concentration, will show more absorbance (as absorbance inverselyproportionalto concentration) As a result, color will be more intense in ease of 0.50 M CuSO_4 (as compared to 0.10 M CuSO_4) Both solution will appear blue Molarity of CuSO_4 (initial), M_i = 0.06 M Let volume be V_i Final condition, V_f = 20 ml M_f = 0.01 M Since no of moles remains constant so M_i V_i = M_f V_f V_i = M_f V_f/M_i = 20 times 0.01/0.06 = 3.33 ml By adding 16.67 ml (20 - 3.33 ml) of water to 0.06 M CuSO_4 (V = 3.33 ml), solution of 0.01 M CuSO_4 can be prepared.