Intro to Chem lab Equipment Weighing –Pan and analytical scales Liquid measure –Use of glassware, liquid meniscus Bunsen Burner –Construction, adjustments,

Intro to Chem lab Equipment• Weighing

– Pan and analytical scales

• Liquid measure– Use of glassware, liquid meniscus

• Bunsen Burner– Construction, adjustments, lighting

• Safety hardware– Eyewash fountain, fire blanket & extinguisher

Utility Pan-Scale

• Resolution 0.010 gram• Maximum ≈ 1000 gram• For routine lab work• “good enough” for most

purposes• “Tare” feature useful• Simply switch on• NO chemicals on pan,

use dish or paper

Analytical Scale

• 0.0001 gm resolution• Maximum ≈ 200 gram• For critical measure• Sensitive to breezes• Sensitive to heat• “Tare” feature• Use tweezers • Fingerprints can matter• NO chemicals on pan

Individual vs. Cumulative weighing

• Weigh empty vessel• Tare Scale (m=0)• Weigh 1st item, record• Re-Tare (optional)• Remove 1st item• Weigh 2nd item, record• Repeat as required• Each is independent• Errors effect only one

• Weigh empty vessel• Tare Scale (m=0)• Weigh 1st item, record• Weigh 2nd item, record• Weigh 3rd item, record• Repeat as required• Differences = item mass• Saves time• Cumulative error issue

Graduated CylindersUse smallest cylinder suitable

small volume = bigger influence , more accurate

Pipette and “Suction Bulb”Three 1-way valves, Exhaust + Fill + Drain

Reading Volume on Glassware

• Glassware calibrated to read at lowest part of surface “meniscus”

• Surface tension pulls liquid up side of glass

• Smaller diameters are more accurate, less volume per increment

• This example ≈ 6.7 ml

Bunsen Burner assembly

Burner Adjustments

• Wheel on bottom controls amount of gas– More gas when “unscrews” counterclockwise

• Upper collar controls air flow– Most air when slots are fully open

• Adjust 2 together for needed flow, best mix– 2-color light& dark blue flame is optimum

Bunsen Burner gas-air mixleft=lack of air (sooty, cooler), right=optimum mix (hottest)

Lighting the Burner

• “Scratcher” is common welder’s ignition tool

• Press flint to abrader then squeeze handle

• Tilting burner helps• Use one burner to light

another, easiest way• Ask for help !

Counter-top utilities

• Electrical– 120 volt household with GFI

protection– Network outlet

• Natural Gas– Gas is “ON” with handle

parallel to hose

• Water– Tap water at desktops, for

cooling (not chem use)– Distilled water at back of

room, gray plastic tap

• Vacuum– Next to gas, for speedy

filtration

Fume Hoods

• Stinky stuff goes here !• Keeps experiment

smells out of classroom• Computer controlled,

more air with greater opening … noisier too

• Sliding door is also a splatter shield.

Ice Maker

• Near Weighing Room• Cooling baths for various

experiments• NO FOOD storage here.• NOT a good idea to eat

chemistry lab ice, could be contaminated !

Fire Extinguishers

• Red canisters on wall• Powder smothers fire

– “ABC” mix inside– Messy but effective

• Pull pin out, squeeze trigger to release pressurized contents

• Single-use, powder clogs release valve

• Pressure gauge should be in “green”

Fire Extinguisher safety pin & ringTwist and remove ring, squeeze handles to spray

Fire Blanket

• Used to put out clothing fires.

• Designed to smother fire, excludes oxygen

• Don’t become the smoking filling of a fire-blanket burrito !

Burns can be avoided!See posted story on chemistry lab accidents

Safety Goggles Required!Goggles offer protection from gas, liquid, solid

Safety glasses only deflect flying objects

Eyewash Fountain & Shower

• Don’t experiment with it!• No drain, will flood lab

– May have a 15 min timer

• A conflict of regulations– Must have eye fountain– Spill might be hazardous– No drain avoids sewer

system contamination.

• NO fun here– Cold water, naked

students, wet floor!

• Emergency use only

Chem Lab Oven

• General drying – Experiment samples– Wet glassware

• Usually set at 110oC• Need to label which

sample is yours, they all look alike

Broken Glass Container

• Cardboard box in lab• Chipped, cracked, or

broke glass goes here• Do NOT use broken

or cracked glassware, could be dangerous

• Minor chips may be repairable, show your instructor if in doubt.

Hazardous Materials, NFPA-704 DiamondSymbol in white for specifics (radioactive, don’t use water, etc.)

Firemen might NOT enter area with danger value >2

NFPA Diamond

NFPA Diamond Symbolsnot always consistent!

NFPA diamond or Gasoline

Safety First!

• Have a GREAT semester in Chemistry!

• SAFETY FIRST is our #1 priority

• Bad examples follow – Possible candidates for “Darwin award”, for

elimination of the unfit.– “don’t do these at home”

How not to work on your car

Maybe they need one more forklift

Creative use of ladders?

How not to transport a bomb

Maybe the guy in shorts is immune

Instructions were “Don’t Feed the Alligators”

Moral of the story…

• Have fun in Chem Lab

• Follow Instructions

• Don’t take chances

• Be careful!

Hopefully not a poisonous one

Lawn Chair Larry (and equiv.)

Burgler falling from Museum