Lab practical - project 1

corrosive

Destroys living tissue on contact

Flammable

Easily ignites and burns rapidly

irritant

Irritates living tissue on contact

oxidizer

Rapidly oxidizes, can result in combustion

poison

May be fatal to humans & animals

sensitizer

Causes severe immune reaction after repeated exposure

Toxic

Causes adverse health effects

A

Fatal

• NFPA: health

B

Aquatic toxicity

• NFPA: none

C

Oxidizer

• NFPA: special hazards

D

Carcinogen and toxic

• NFPA: health

E

Flammable

• NFPA: flammability

F

Irritant, skin sensitizer

• NFPA: health

G

Explosive

• NFPA: instability

H

Gas under pressure

• NFPA: none

I

Corrosive

• NFPA: health

What are the goals for project 1?

• determine what dyes are in Gatorade

• Determine dye concentration in Gatorade

Project 1 steps

Part 1

Materials: Volumetric pipet, volumetric flask, 2 beakers (1 for waste 1 for solution), disposable pipettes, and a pipet bulb

1. Create a dilution plan using MconcVconc=MdilVdil (mL and μM)

• Mconc=concentration of stock solution

• Vcocn=volume of volumetric pipette OR volume of solute (dye) you pipette

• Mdil=concentration of diluted stock

• Vdil=volume of volumetric flask

Part 2

1. Pre-rinse volumetric flask with solvent (DI water)

2. Pre-rinse volumetric pipette with DI water

3. pre-rinse volumetric pipette with solute (you’re allowed to blow out liquid)

4. transfer dye to volumetric flask (DO NOT BLOW OUT AT THIS STEP)

5. Create dilutions - solute is dye, solvent is DI water

Part 3

1. Pre-rinse cuvette with solvent (DI water), place into waste, wipe. fill with DI water, wipe, then calibrate/blank. pour into waste when done

2. Use the most concentrated solution to get lambda max. pre-rinse cuvette with the most concentrated solution + wipe, then pour into waste. fill cuvette with most concentrated solution again, then press “play”. get the lambda max (highest absorbance value)

3. Mode → events with entry → change name and change units to (μM). change the LabQuest’s wavelength to your lambda max

4. Find the absorbance spectrums for all concentrations, making sure to start collecting from the LOWEST concentrated solution to the HIGHEST concentrated solution. use the same cuvette every time to eliminate contamination + pre-rinse with DI water/the solution + wipe every time

5. press “keep” to keep the absorbance value once it has stabilized. repeat for all solutions, and press stop when you’re done.

beer’s law

A  = ε C l

A=absorbance (at λ_max, no units)

ε  =  molar absorptivity coefficient (units = L/mol(cm))

C  = concentration of absorbing species (units = mol/L)

l  =  path length (units = cm)

• the y=mx+b equation from the beer’s law plot is used

Order the steps for using a SDS to fully understand the hazards associated with the chemical.

1. Compare label info to make sure you have the right SDS

2. Determine GHS symbol

3. Look at procedures for safe handling

What do jagged lines in absorbance spectrums mean?

detector is saturated

Argumentation

construction of scientific ideas by a group of people

Claim

A conclusion supported by data

Evidence

a relationship between variables

Reasoning

Justification that connects data trends to scientific laws or theory