Chemistry Video 17 Flashcards
Beaker
Holding, mixing liquids. Not precise for measurements. Cylindrical with spout for pouring
Graduated cylinder
Measure volumes. Tall and cylindrical with spout for pouring. Ideal for measuring volume to the nearest millimeter. Read from bottom of CONCAVE meniscus.
Erlenmeyer Flask
Similar to beaker, but taper inwards. Transfer and mix liquids. Not for measurements
Volumetric flask
wide bulb with narrow neck on top. For making solutions of one particular volume, which is the volume listed on the line at the neck of the flask.
Filter flask
For vacuum filtration. Has place for vacuum pump to hook on. Precipitate will collect on an attached Buchner funnel
Test tubes
transfer and mixing of liquid. Small quantities.
Pipet
Measurement and transfer of precise liquid.
Buret
Delivering liquid precisely, used for titration
Bunsen burner
heating a reaction flask. Safety and convenience
Calorimeter
Measuring heat transfer
Digital balance
Measure mass to high precision. Use filter paper and zero the scale.
pH meter
Measures pH of solution. Can be analog or digital and must be calibrated with solutions of known pH
Buchner funnel
Used in conjunction with filter flask during filtration. Collecting solid by filtration. This is the funnel used to collect solid precipitate on filter paper
Gravity funnel
collecting solid by filtration
Powder funnel
adding solid reagents to a flask
Separatory funnel
separating immiscible liquids
Bomb calorimeter
Allows highly explosive reactions and to measure heat release
Coffee cup calorimeter
Styrofoam is good insulator
Centrifuge
Separate solids or liquids in heterogenous mixtures. Tubes spin fast, make centrifugal force. Pellet is solid and at the bottom of tube. Liquid is supernatant is above the solid. Tubes must be balanced on opposite sides with the same mixture in equal volume
After the centrifugation process has finished, we can simply separate the liquid supernatant from the solid pellet by using either a pipette or by decanting the liquid. In some cases, filtration can also be used. Simple decantation usually involves just pouring the liquid out of the original vessel, leaving the solid behind.
Titration
Analyte in Erlenmeyer Flask and titrant in buret. Colour changes at equivalence point.
Filtration
Separates solids and liquids in a mixture. Place filter paper on a Buchner funnel, then put in filter flask hooked to vacuum pump. Put mixture through on filter paper, the solid will stay on filter and liquid is pulled through the funnel. Let the solid dry and scrape it off the filter paper.
Drying/cleaning
Wash glassware with soap and water in tap and rinse with deionized (DI) water. Place on drying rack or oven. Do not place volumetric glassware (i.e. buret and volumetric flask) because the glass can warp and affect calibration
Percent error
[(experimental value – actual value) / actual value] *100%
Systematic error
From flawed equipment or experimental design. Can be detected and accounted for.
Random error
Any human error. Common to be poor estimation of measurement
Spill neutralizer
Used to treat pools of harmful liquid. Neutralizes chemical spills
Fume hood
Location for performing potentially dangerous chemistry. Equipped with ventilation so that harmful vapours are sucked up into an exhaust. The glass should be pulled down when in use
Eye wash
For chemicals in eye
Safety shower
For chemicals on skin
Simple distillation
A method of separating liquids of different boiling points. Used for liquids with boiling points less than 150 degrees Celsius and more than 25 degrees Celsius apart.
Fractional distillation
A method of separating liquids of different boiling points. Used for liquids with boiling points that are less than 25 degrees Celsius apart.
Vacuum distillation
A method of separating liquids of different boiling points. Used for liquids with boiling points more than 150 degrees Celsius
Boiling flask
Swirl and heat liquids
Has a round bottom with a longer neck. Used to swirl and heat solutions, but is not used for measuring volume. It cannot stand up by itself.
Most to least precise
Pipette > Buret/Volumetric flask > Graduated cylinder > Beaker/Erlenmeyer Flask
Droppers
small glass tubes with a rubber bulb on one end. Droppers are used to deliver a liquid (usually an indicator), in a drop-wise fashion. They are also known as Pasteur pipettes.
End point
the point at which an observable property (e.g. color change) occurs and this is associated with either being at or near the equivalence point. Any deviation of the endpoint from the equivalence point is known as titration error.
Fire extinguisher
used to exterminate any fires. You should aim the discharge from the extinguisher at the base of the fire that is the closest to you. You should always position yourself in between the fire and the exit. Extinguishers should only be used for solvent or electrical fires and not those resulting from paper or wood.
Lab coat
should be worn always during the laboratory. If you get chemicals on your skin, rinse with lots of water and seek medical attention if needed. You should also wear closed- toe shoes.
Safety goggles
should be worn always during the laboratory. You should avoid wearing eye contacts in the lab, even with safety goggles, as dangerous fumes can concentrate under the glasses and cause complications.
Rubber or disposable gloves
Gloves should be worn whenever you are dealing with any potentially harmful chemicals.
Broken glass container
most labs have a container for disposal of any broken glass. Broken glass should be cleaned up as soon as possible, with caution, using a dustpan.
Disposal of solutions
acids, alkalis, or other water miscible solutions can be flushed down the drain with copious amounts of water. Organic and other water immiscible chemicals should NOT be flushed down the drain but instead disposed of in the appropriate waste bin in the laboratory.
Volumetric vs graduated
The term “volumetric” refers to any glassware that has a single marking that indicates a specific volume. These are generally more precise than graduated glassware. In contrast, “graduated” refers to any glassware that has several markings indicating different volume levels.
