Method, Risk Assessment

risk assessment

SAFETY PRECAUTIONS: Wear your SAFETY GOGGLES. corrosive. If any solutions containing nitric acid splash onto your hands clothing wash them off immediately with copious amounts of running water.

WASTE DISPOSAL: All waste from this experiment should be poured into the INORGANIC WASTE containers in the fume hood.

Method

Part 1: Finding the relationship between absorbance and [FeSCN²⁺]

Label 3 medium-sized test tubes.

The Table below shows the amounts of the concentrated 0.20 M Fe(NO_{3)3 (in 1 M HNO3) solution, 2.00 χ 10}–3 _{M KSCN solution,} and purified water that should be added to each tube.

Pipet the approximate amount of each solution into each tube. (Record the exact amount of each solution that you actually add. You will need to use these actual amounts in your calculations.)

Obtain three separate small pieces of parafilm.

Close the top of each test tube with the parafilm.

Mix each solution thoroughly by inverting the test tube several times.

Record your observations. (How do the colours of the five solutions compare?)

Zero the spectrophotometer.

Then, measure and record the absorbance of each solution at 447 nm.

Part 2: Determining the equilibrium constant

Label 5 medium-sized test tubes.

The Table below shows the amounts of 2.00 χ 10^–3 M Fe(NO_{3)3 (in 1 M HNO3) solution, 2.00 χ 10}–3 _{M KSCN solution, and purified water} that should be added to each tube.

Pipet the approximate amount of each solution into each tube. (Record the exact amount of each solution that you actually add. You will need to use these actual amounts in your calculations.)

Obtain five separate small pieces of parafilm.

Close the top of each test tube with the parafilm.

Mix each solution thoroughly by inverting the test tube several times. Record your observations.

Measure and record the absorbance of each solution at the 447 nm.