1. A student has been asked to make 100.0 mL of 0.150 M CuSO4(aq) solution for a spectrophotometry experiment. The following laboratory equipment is available for preparing the solution: centigram balance, weighing paper, funnel, 10mL beaker, 150mL beaker, 50 mL graduation cylinder,100 mL volumetric flask, 50mL buret, and distilled water.
a. Calculate the mass of the solid CuSO4(s) required for the preparation (according to significant figures).
b. Briefly describe the essential steps to most accurately prepare the 0.150 M CuSO4(aq) from the solid CuSO4(s) using the equipment above.
c, Draw a particulate diagram that shows the interaction between water molecules and the Copper (II) sulfate molecules after some of the CuSO4(s) dissolved into CuSO4(aq).
d. When performing experiments with a blue solution (like the CuSO4(aq) solution) the wavelength of the spectrophotometer needs to be set to 635 nm in order to get the best absorption results. At this wavelength, how much energy is being transmitted toward the solution (according to significant figures)?
e. A different student tried to accomplish this same task, but chose to use hexane (C6H14) as the solvent instead of water. Explain why this student will not be able to complete their task.
f. At STP (standard temperature and pressure = 0 degrees Celsius and 1 atm) a pure sample of hexane (C6H14) has a higher vapor pressure than a pure sample of water (H2O) or a pure sample of CuSO4. Which substance would have the next highest vapor pressure? Justify your answer in terms of the attractive forces that hold the pure substances together.
