Chemistry Video 17

Question 1

Beaker

Answer 1

Holding, mixing liquids. Not precise for measurements. Cylindrical with spout for pouring

Question 2

Graduated cylinder

Answer 2

Measure volumes. Tall and cylindrical with spout for pouring. Ideal for measuring volume to the nearest millimeter. Read from bottom of CONCAVE meniscus.

Question 3

Erlenmeyer Flask

Answer 3

Similar to beaker, but taper inwards. Transfer and mix liquids. Not for measurements

Question 4

Volumetric flask

Answer 4

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.

Question 5

Filter flask

Answer 5

For vacuum filtration. Has place for vacuum pump to hook on. Precipitate will collect on an attached Buchner funnel

Question 6

Test tubes

Answer 6

transfer and mixing of liquid. Small quantities.

Question 7

Pipet

Answer 7

Measurement and transfer of precise liquid.

Question 8

Buret

Answer 8

Delivering liquid precisely, used for titration

Question 9

Bunsen burner

Answer 9

heating a reaction flask. Safety and convenience

Question 10

Calorimeter

Answer 10

Measuring heat transfer

Question 11

Digital balance

Answer 11

Measure mass to high precision. Use filter paper and zero the scale.

Question 12

pH meter

Answer 12

Measures pH of solution. Can be analog or digital and must be calibrated with solutions of known pH

Question 13

Buchner funnel

Answer 13

Used in conjunction with filter flask during filtration. Collecting solid by filtration. This is the funnel used to collect solid precipitate on filter paper

Question 14

Gravity funnel

Answer 14

collecting solid by filtration

Question 15

Powder funnel

Answer 15

adding solid reagents to a flask

Question 16

Separatory funnel

Answer 16

separating immiscible liquids

Question 17

Bomb calorimeter

Answer 17

Allows highly explosive reactions and to measure heat release

Question 18

Coffee cup calorimeter

Answer 18

Styrofoam is good insulator

Question 19

Centrifuge

Answer 19

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.

Question 20

Titration

Answer 20

Analyte in Erlenmeyer Flask and titrant in buret. Colour changes at equivalence point.

Question 21

Filtration

Answer 21

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.

Question 22

Drying/cleaning

Answer 22

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

Question 23

Percent error

Answer 23

[(experimental value – actual value) / actual value] *100%

Question 24

Systematic error

Answer 24

From flawed equipment or experimental design. Can be detected and accounted for.

Question 25

Random error

Answer 25

Any human error. Common to be poor estimation of measurement

Question 26

Spill neutralizer

Answer 26

Used to treat pools of harmful liquid. Neutralizes chemical spills

Question 27

Fume hood

Answer 27

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

Question 28

Eye wash

Answer 28

For chemicals in eye

Question 29

Safety shower

Answer 29

For chemicals on skin

Question 30

Simple distillation

Answer 30

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.

Question 31

Fractional distillation

Answer 31

A method of separating liquids of different boiling points. Used for liquids with boiling points that are less than 25 degrees Celsius apart.

Question 32

Vacuum distillation

Answer 32

A method of separating liquids of different boiling points. Used for liquids with boiling points more than 150 degrees Celsius

Question 33

Boiling flask

Answer 33

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.

Question 34

Most to least precise

Answer 34

Pipette > Buret/Volumetric flask > Graduated cylinder > Beaker/Erlenmeyer Flask

Question 35

Droppers

Answer 35

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.

Question 36

End point

Answer 36

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.

Question 37

Fire extinguisher

Answer 37

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.

Question 38

Lab coat

Answer 38

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.

Question 39

Safety goggles

Answer 39

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.

Question 40

Rubber or disposable gloves

Answer 40

Gloves should be worn whenever you are dealing with any potentially harmful chemicals.

Question 41

Broken glass container

Answer 41

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.

Question 42

Disposal of solutions

Answer 42

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.

Question 43

Volumetric vs graduated

Answer 43

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.