Spectrophotometry Week 8 LAB SKILL 8.1 DETERMINE THE COLOUR OF SOLUTION USING THE SPECTROPHOTOMETER Wavelength (nm) Colour of light 400-450 violet - 2Us 450-480 blue - 465 480-510 blue-green - uas 510-550 green - 50 550-570 yellow-green - 560 570-590 yellow 580 590-630 orange G LO 630-700 red 665 You will get 8 different coloured solutions. 1. What are the colours of these solutions? Write your opinion in the last row of the table. 2. Determine the colour of the same solutions using the spectrophotometer. Load 1ml of each solution into a separate cuvette. Load water (the solvent) into a cuvette as well. This will act as the BLANK. Place the water blank into the first spot and fill the other five spaces with coloured solutions. (You will have three solutions remaining - test these later). IMPORTANT: DO NOT remove the solutions from the spectrophotometer, until you have finished measuring ALL required absorbances. 3. Set the wavelength to the middle of the first range provided in the table (e.g. 425mm for the range 400-450) 4. Zero the spectrophotometer before reading the absorbance of each solution. 5. Change the wavelength to the next value in the table (465nm), and repeat the process remembering to zero before reading the absorbance. Record the absorbance readings for all solutions in Table 1 on page 78. Repeat for all wavelengths until you have finished all readings for the first five solutions. 6. Repeat the same process for the remaining three solutions. 74