SPE: Spectrophotometric Determination of Copper

Before coming to lab, you should:

1. Read the assigned Background reading material in Cooperative Chemistry Laboratory Manual and Chemistry and Chemical Reactivity (See laboratory handout for page numbers.)
2. Answer the following questions on a separate sheet of paper: (Turn in to your lab instructor at beginning of lab.)

Show all calculations. Report all answers to the correct number of significant figures and with the correct units.

1. (1 pt) A solution absorbs light at 454 nm. What color light is being absorbed?

2. (4 pts) Outline in 5 short steps how to calibrate a Spec 20.

3. (1 pts) How many mL of a 2.50 M solution of Na₂SO₄ are needed to make 250 mL of 0.250 M solution of Na₂SO₄?

5. (4 pts) This lab will familiarize you with preparing a Beer’s Law Plot, which is prepared by plotting _____________ vs. _____________. Briefly explain, in three steps, how you will use this graph to find the concentration of an unknown copper solution.