Questions and Answers
Apply ___ or ___ to the glass tubing and the rubber stopper when inserting the tubing through the stopper.
water, glycerol
Glassware should always first be cleaned with a soap or detergent using ___ water.
tap
Safety information about any chemical can be obtained from a collection of ___ generally located in the stockroom or at several websites on the internet.
MSDS
In preparing an aqueous solution of a solid in a volumetric flask, always add ___ to the volumetric flask first.
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The ___ sign is used to identify a potential danger in handling a chemical in this manual.
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Always place ___ or a ___ on the balance pan to measure the mass of a chemical on a balance.
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The mass difference between the mass of the sample and the mass of the weighing paper is called the ___ of the sample.
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In handling small volumes of solutions, the use of a ___ is the choice of most chemists.
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A 75-mm (~3 inch) test tube has a volume of about ___ ml.
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Always use a ___ to assist in the transferring of a solution from one vessel to another.
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A precipitate is flushed from a beaker using the solvent contained in a ___.
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A bowl of a filter funnel used for gravity filtration should always be kept about ___ full with solution during the filtering process.
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To remove the suction during a vacuum filtration procedure, first ___ and then ___.
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A nonluminous flame supplied with a reduced supply of fuel is called a ___ flame.
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A test tube should be less than ___ full when heated directly with a 'cool' flame.
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In heating a liquid in a test tube directly with a 'cool' flame, the test tube should be moved in and out of the flame with a circular motion with most of the heating applied at the ___ of the liquid.
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The reading and recording of a volume of liquid in volumetric glassware should include all digits read directly from the calibration marks on the glassware plus ___.
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After the buret is filled with titrant, the stopcock should be opened to allow some titrant to drain through the tip. The purpose of this procedure is to ___.
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A ___ is used to touch a solution to test paper for measuring the acidity/basicity of a solution.
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A 'yellow 4' appears on a reagent bottle: 'yellow' refers to the ___ of the chemical and the '4' indicates that the chemical ___.
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What does 'Blue' on MSDS mean?
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What does 'Red' on MSDS mean?
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The bottom white symbol on MSDS is left for?
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The final step in cleaning glassware is to dry it with a clean paper towel.
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Glassware is clean if no water droplets cling to its wall.
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A chemical with a blue hazard label (#3 rating) means that the chemical is highly reactive.
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To avoid waste in the use of chemicals, always return the unused portion directly to the original reagent bottle.
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If you are uncertain as to how to dispose of a chemical after use, dumping it into the sink, followed by a flush with copious amounts of water, is always a safe disposal procedure.
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Most laboratory balances in the general chemistry laboratory can measure the mass of a substance to less than 0.01g.
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Water-soluble gases can be collected by water displacement.
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Use a spatula to transfer chemicals from a reagent bottle.
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Never lay the stopper from a liquid reagent bottle on the laboratory bench.
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Two equal folds are used to prepare a piece of circular filter paper from a funnel.
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The funnel stem of a filter funnel should touch the side of the receiving flask during the filtering procedure.
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The minimum number of centrifuge tubes that should be placed into a centrifuge during its operation is two.
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Given a choice, always use a fume hood in lieu of an improvised hood.
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The heat source for heating and evaporating flammable liquids should be a hot plate.
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The thumb is the digit of choice in controlling the dispensing of a liquid from a pipet.
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A pipet should be rinsed several times with the liquid or solution before it is finally filled.
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Blow out the solution remaining in the pipet tip after the solution has drained from the pipet.
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Always read the bottom of the meniscus for a liquid in glassware.
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Use a collapsed rubber pipet bulb to draw liquid into a pipet.
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A buret must always be filled to the top (the zero mark) before every titration procedure.
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After the endpoint is reached in a titration, the volume of titrant should be read immediately.
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A half-drop of titrant can be dispensed from a buret.
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A good chemist, without reservation, smells all chemicals.
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Acids cause litmus paper to appear red.
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Litmus paper should be placed directly into the test solution to determine its acidity/basicity.
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Study Notes
Laboratory Techniques
- To ease the insertion of glass tubing into a rubber stopper, apply water or glycerol to both.
- Always clean glassware first with soap or detergent using tap water.
- Safety information for chemicals can be found in Material Safety Data Sheets (MSDS), available in stockrooms or online.
- When preparing an aqueous solution in a volumetric flask, start by adding water first.
- The international caution sign indicates potential dangers in chemical handling.
- Use weighing paper or a dry container when measuring chemical mass on a balance.
- The tared mass of a sample is the mass difference between the sample and the weighing paper.
- Small test tubes are the preferred choice for handling small volumes of solutions.
- A standard 75-mm test tube can hold approximately 3 ml of liquid.
- Always use a stirring rod to transfer a solution between vessels.
- A wash bottle is utilized for flushing precipitates from beakers with solvent.
- During gravity filtration, a filter funnel's bowl should remain half to one-third full of the solution.
- For vacuum filtration, disconnect the hose and turn off the water to remove suction safely.
- A cool flame has a reduced fuel supply and is used for specific heating tasks.
- Test tubes heated directly with a cool flame should be filled to less than one-third of their capacity.
- Move the test tube in and out of the cool flame with a circular motion, applying heat primarily to the liquid's top.
- Record liquid volumes in volumetric glassware including all digits from calibration marks and one uncertain digit.
- To eliminate air bubbles, allow some titrant to drain from the buret tip after filling it.
- Litmus paper is used to test the acidity or basicity of a solution.
- The color coding on reagent bottles indicates reactivity and hazard levels, e.g., "yellow 4" signifies explosive reactivity.
- Blue on an MSDS indicates a health hazard, while red indicates a fire hazard.
- The bottom white symbol on an MSDS is reserved for specific hazards.
- Cleaning glassware concludes with evaporation rather than drying with paper towels.
- Glassware is considered clean if no water droplets cling to its walls.
- A blue hazard label (#3 rating) does not imply high reactivity; yellow indicates reactivity.
- Unused chemicals should not be returned to the original reagent bottle; share excess with other chemists instead.
- Never dispose of chemicals by dumping them in the sink; follow proper procedures and instructions.
- General chemistry balances can measure mass to 0.01 g, but not less.
- Water-soluble gases should not be collected using the water displacement method; it is only effective for water-insoluble gases.
- Using a spatula to transfer chemicals from a reagent bottle is discouraged.
- Do not place liquid reagent stoppers on the laboratory bench.
- Two equal folds are sufficient to prepare circular filter paper for a funnel.
- Ensure the funnel stem of a filter funnel touches the side of the receiving flask during filtering.
- At least two centrifuge tubes should be used when operating a centrifuge for balance.
- Always prefer using a fume hood over makeshift hoods in laboratory settings.
- A hot plate is the recommended heat source for evaporating flammable liquids.
- Control the dispensing of liquid from a pipet using the forefinger, not the thumb.
- Rinse a pipet multiple times with a solution before filling it for accurate measurements.
- Do not blow out the remaining liquid in a pipet tip after draining; it is accounted for in calibration.
- Always read the bottom of the meniscus when measuring liquids in glassware.
- Use a collapsed rubber pipet bulb for drawing liquid into a pipet.
- A buret should not be filled to the top before titration; instead, it should be filled just below the zero mark.
- Read the buret volume after 10-15 seconds post-titration to ensure accuracy.
- A half-drop of titrant can indeed be dispensed from a buret.
- Chemists should not smell all chemicals indiscriminately; only do so when safe and necessary.
- Acids turn litmus paper red, while bases turn it blue.
- Litmus paper should not be directly immersed into the test solution; instead, use a stirring rod that has been in contact with the solution first.
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Test your knowledge of essential laboratory techniques with these flashcards. Each card focuses on important terms and definitions related to safety and equipment handling in a laboratory setting. Perfect for students and professionals looking to refresh their knowledge.
