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Questions and Answers
Apply ___ or ___ to the glass tubing and the rubber stopper when inserting the tubing through the stopper.
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.
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.
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.
In preparing an aqueous solution of a solid in a volumetric flask, always add ___ to the volumetric flask first.
The ___ sign is used to identify a potential danger in handling a chemical in this manual.
The ___ sign is used to identify a potential danger in handling a chemical in this manual.
Always place ___ or a ___ on the balance pan to measure the mass of a chemical on a balance.
Always place ___ or a ___ on the balance pan to measure the mass of a chemical on a balance.
The mass difference between the mass of the sample and the mass of the weighing paper is called the ___ of the sample.
The mass difference between the mass of the sample and the mass of the weighing paper is called the ___ of the sample.
In handling small volumes of solutions, the use of a ___ is the choice of most chemists.
In handling small volumes of solutions, the use of a ___ is the choice of most chemists.
A 75-mm (~3 inch) test tube has a volume of about ___ ml.
A 75-mm (~3 inch) test tube has a volume of about ___ ml.
Always use a ___ to assist in the transferring of a solution from one vessel to another.
Always use a ___ to assist in the transferring of a solution from one vessel to another.
A precipitate is flushed from a beaker using the solvent contained in a ___.
A precipitate is flushed from a beaker using the solvent contained in a ___.
A bowl of a filter funnel used for gravity filtration should always be kept about ___ full with solution during the filtering process.
A bowl of a filter funnel used for gravity filtration should always be kept about ___ full with solution during the filtering process.
To remove the suction during a vacuum filtration procedure, first ___ and then ___.
To remove the suction during a vacuum filtration procedure, first ___ and then ___.
A nonluminous flame supplied with a reduced supply of fuel is called a ___ flame.
A nonluminous flame supplied with a reduced supply of fuel is called a ___ flame.
A test tube should be less than ___ full when heated directly with a 'cool' flame.
A test tube should be less than ___ full when heated directly with a 'cool' flame.
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.
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.
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 ___.
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 ___.
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 ___.
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 ___.
A ___ is used to touch a solution to test paper for measuring the acidity/basicity of a solution.
A ___ is used to touch a solution to test paper for measuring the acidity/basicity of a solution.
A 'yellow 4' appears on a reagent bottle: 'yellow' refers to the ___ of the chemical and the '4' indicates that the chemical ___.
A 'yellow 4' appears on a reagent bottle: 'yellow' refers to the ___ of the chemical and the '4' indicates that the chemical ___.
What does 'Blue' on MSDS mean?
What does 'Blue' on MSDS mean?
What does 'Red' on MSDS mean?
What does 'Red' on MSDS mean?
The bottom white symbol on MSDS is left for?
The bottom white symbol on MSDS is left for?
The final step in cleaning glassware is to dry it with a clean paper towel.
The final step in cleaning glassware is to dry it with a clean paper towel.
Glassware is clean if no water droplets cling to its wall.
Glassware is clean if no water droplets cling to its wall.
A chemical with a blue hazard label (#3 rating) means that the chemical is highly reactive.
A chemical with a blue hazard label (#3 rating) means that the chemical is highly reactive.
To avoid waste in the use of chemicals, always return the unused portion directly to the original reagent bottle.
To avoid waste in the use of chemicals, always return the unused portion directly to the original reagent bottle.
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.
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.
Most laboratory balances in the general chemistry laboratory can measure the mass of a substance to less than 0.01g.
Most laboratory balances in the general chemistry laboratory can measure the mass of a substance to less than 0.01g.
Water-soluble gases can be collected by water displacement.
Water-soluble gases can be collected by water displacement.
Use a spatula to transfer chemicals from a reagent bottle.
Use a spatula to transfer chemicals from a reagent bottle.
Never lay the stopper from a liquid reagent bottle on the laboratory bench.
Never lay the stopper from a liquid reagent bottle on the laboratory bench.
Two equal folds are used to prepare a piece of circular filter paper from a funnel.
Two equal folds are used to prepare a piece of circular filter paper from a funnel.
The funnel stem of a filter funnel should touch the side of the receiving flask during the filtering procedure.
The funnel stem of a filter funnel should touch the side of the receiving flask during the filtering procedure.
The minimum number of centrifuge tubes that should be placed into a centrifuge during its operation is two.
The minimum number of centrifuge tubes that should be placed into a centrifuge during its operation is two.
Given a choice, always use a fume hood in lieu of an improvised hood.
Given a choice, always use a fume hood in lieu of an improvised hood.
The heat source for heating and evaporating flammable liquids should be a hot plate.
The heat source for heating and evaporating flammable liquids should be a hot plate.
The thumb is the digit of choice in controlling the dispensing of a liquid from a pipet.
The thumb is the digit of choice in controlling the dispensing of a liquid from a pipet.
A pipet should be rinsed several times with the liquid or solution before it is finally filled.
A pipet should be rinsed several times with the liquid or solution before it is finally filled.
Blow out the solution remaining in the pipet tip after the solution has drained from the pipet.
Blow out the solution remaining in the pipet tip after the solution has drained from the pipet.
Always read the bottom of the meniscus for a liquid in glassware.
Always read the bottom of the meniscus for a liquid in glassware.
Use a collapsed rubber pipet bulb to draw liquid into a pipet.
Use a collapsed rubber pipet bulb to draw liquid into a pipet.
A buret must always be filled to the top (the zero mark) before every titration procedure.
A buret must always be filled to the top (the zero mark) before every titration procedure.
After the endpoint is reached in a titration, the volume of titrant should be read immediately.
After the endpoint is reached in a titration, the volume of titrant should be read immediately.
A half-drop of titrant can be dispensed from a buret.
A half-drop of titrant can be dispensed from a buret.
A good chemist, without reservation, smells all chemicals.
A good chemist, without reservation, smells all chemicals.
Acids cause litmus paper to appear red.
Acids cause litmus paper to appear red.
Litmus paper should be placed directly into the test solution to determine its acidity/basicity.
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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