Warm-up 24 Aug 10Page in ISN

1) Which of these will give the most precise measure of a 10-milliliter volume?

2) Only 10% of the electrical energy operating a lightbulb is changed into visible light. Which instrument helps identify the energy change occurring to most of the remaining 90%?

A. Triple-beam balance B. Thermometer C. Magnifying glass D. Prism

Safety Video

Lab Safety Review

• Accidents in the lab, as in the home or work place, can be prevented: – Stop to think!– Common sense will help, if exercised – What will be the consequences of what I do

next? – If in doubt, ask the teacher.

Lab Safety Review• Students must wear approved safety goggles when in the lab.

• Avoid floppy garments; avoid things that dangle • These get tangled up in equipment or glassware and cause accidents • Avoid long, loose hair styles for the same reason. • When Bunsen burners are in use, long hair sometimes catches on fire

– The Safety Code of most schools will not approve of open foot ware; so avoid sandals and flip flops.

Lab Safety (handling acids or bases)

• Many schools will require the use of personal protective equipment, such as gloves. – However, cream-colored latex gloves (see photo) are no

longer recommended (due to allergic responses). – "Vinyl" gloves or "nitrile" gloves (often green or blue in

color) are preferred.

Lab Safety Equipment

• The following must be in the lab, in a recognizable location, and fully functional.– Fire Extinguisher

• Fire Blanket

Lab Safety Equipment cont…

– Fire Blanket• Usage

– Yank the blanket out of the wall holder. – Wrap it around the victim to smother the fire.

Lab Safety Equipment cont…– Eye Wash

• If you get something from the lab in your eye— – GET IT OUT IMMEDIATELY! – Don't wait until lunch or the last period!

• Run some water through the eyewash fountain before you use it. • Retract your eyelid (hold it open); • Don’t squint your eyes this restricts water access. • Run fresh water over your eye for several minutes. If the water at your school is COLD • Wash your eyes INTERMITTENTLY • Rest in between rinses. • Go to the school nurse immediately afterward.

Lab Safety Equipment cont…

– Use of the Fume Hood• use the HOOD for reactions that give off vapors,

especially smelly vapors. • The draft of the HOOD will sweep away vapors so that

the lab itself maintains reasonable air quality.

Lab Safety Equipment cont…

– Safety Shower• Shower should be used for dire EMERGENCY only! • If you (or a lab mate) is ON FIRE, position yourself (or your lab mate) under the

safety shower. • Pull the handle—a deluge of water will result. Flames will be rapidly extinguished.

Lab Safety cont….

• Picking up broken glass– Sweep it up right away– Don’t track it all period– Place the broken glass in

a “SHARP’S Container”– If such a container is not

available, a milk carton is an acceptable substitute

Lab Safety cont….• Material Safety Data Sheets

(MSDS)– The MSDS sheet lists the known

dangers of the chemical in question.

– Your school should keep a file of MSDS sheets.

– Many people feel that the MSDS sheets overstate the dangers.

– Make sure you use the right MSDS sheet for the right chemical, as many chemical names sound similar.

– The catalogs of major suppliers also list useful safety information.

Lab Safety cont….• Safety Warning Diamond

– Know the significance of these symbols. • You will see these frequently in adult

life. • RED is FIRE DANGER

– rated on a 0-4 basis. » If, for example, ether is

present, a very high rating of 4 would be indicated.

• Yellow indicates REACTIVITY danger. – often "WATER REACTIVE" dangers

» Sodium metal, if present, would require a 4 rating.

» Sodium represents a danger to firemen, who might come busting into this area with a high pressure hose.

• BLUE represents HEALTH HAZARDS, • WHITE signifies specific hazards, e.g.

oxidizers, acids, bases, or corrosive materials.

Lab Safety cont…– No UNAUTHORIZED

experiments! • These are terrible dangers in

unskilled hands

– No EATING or DRINKING in the LAB. • A good practice is to assume

everything in the lab is toxic.

– DO NOT drink from lab equipment. • NOT EVEN distilled water

Proper Use of Equipment

• Pipets– When using pipets, DO

NOT suck the liquid into the pipet directly by mouth. • Frequent mistakes, even

by skilled lab workers, lead to the liquid reaching the mouth

– DO use a rubber bulb to create a vacuum

Proper Lab Procedure

• Testing of Odors– Do NOT smell the flask

directly

– If you absolutely must test the odor, carefully waft the vapor from the flask toward your nose with your hand. • Keep the flask quite

distant from your face.

Proper Lab Procedure cont….• DO NOT add WATER to

CONCENTRATED ACID. • The heat generated may cause

splattering. • Your school probably will not allow

you to use concentrated acids anyway, so keep this info in mind for future reference

– If necessary to prepare certain solutions, DO add ACID to WATER (instead of the reverse order of addition). • The heat generated will be less, but

splattering still may occur. • A good practice in all lab operations

is to keep things at arm’s length. • Always wear eye protection.

Proper Lab Procedure (before Lab)

• Read the experimental procedure ahead of lab.

• NOT as y-o-u d-o t-h-e p-r-o-c-e-d-u-r-e – Mistakes, then, are

common.

Proper Lab Procedure (Horseplay)

• In a laboratory setting, horseplay, even if good-natured, is

absolutely unacceptable. – No pushing! – No shoving!

Proper Lab Procedure (Leaving)• Clean your area

– Pick up and throw away any trash– Wipe off the counters with

cleaner– Clean all equipment that was

used and place back into its proper location

– Finish your lab notes

• Exit the lab in an orderly manner.

• Again: no running, no pushing, no shoving.

• Remember, I dismiss you from lab….not the bell

Safety Video