# BEER'S LAW LAB

### By: Hunter Liles

## UNDERSTANDING BEERS LAW

**- The amount of light that penetrates the solution and strikes the photocell is used to compute the absorbance of each solution.**

*Absorbance*** Concentration** - The concentration of the anesthesia solution is determined by measuring its absorbance with the Colorimeter.

(When a graph of *absorbance* vs. *concentration* is plotted for the standard solutions, a direct relationship should result. The direct relationship between *absorbance* and *concentration* for a solution is known as **Beer's Law**.)

## BACKGROUND INFORMATION

## LAB SETUP

- First plug in the Colorimeter to the computer interface and use Logger Pro.
- Then fill the cuvettes with 3/4's full of the different solutions
- Holding the cuvette by the ribbed sides, place it into the slot of the Colorimeter.
- Calibrate the Colorimeter.
- Collect the data, then repeat until finished.
- Draw a graph and put a line of best fit on it.

(DONT forget to test the mystery solution)

## Colorimeter This is the Colorimeter that is used during the lab. Make sure to plug this into your laptop and calibrate it. | ## Cuvettes The cuvettes are suppose to be filled 3/4 full of solution. Be careful putting the cuvettes in the calorimeter. Place the ribbed sides on edges and the clear side facing forward. | ## Solution This is the solution that you fill the cuvettes' 3/4 full. The solutions are labeled on each of the beakers. |

## Colorimeter

## Cuvettes

## HOW TO MAKE A % SOLUTION

- Express the % of a solution as a decimal.
**Ex: 5% = 0.05** - Multiply the decimal by the total volume.
**Ex: 0.05 x 1000mL = 50mL (ethylene glycol needed)** - Subtract the volume of the solute from the total solution volume.
**Ex: 1000mL (total solution volume) - 50mL (ethylene glycol volume) = 950mL (water needed)** - Dissolve 50mL ethylene glycol in about 950mL of water. Finally, bring the final volume up to 1000mL of water.

**50mL ethylene glycol / 1000mL solution x 100 = 5% ethylene glycol solution**

## OBSERVATIONS

## CONCLUSIONS

2. Since Elda didn't die from the anesthesia she could have died from other multiple things. Elda could have died from old age during the surgery or from a human mistake.

3. Beer's Law helped me solve this case by allowing me to figure out the concentration and absorbance of a solution which helped me determine if Aunt Elda received too much anethesia.