Chem Notes Ch 1

Question 1

Beaker

Answer 1

Wide-mouth vessel with a spout at the top rim, different sizes, not accurate for measuring volumes. Heating, stirring, mixing solutions

Question 2

Graduated cylinder

Answer 2

For general measurement of volume of liquid. Narrow and tail container, with measurement markings. Read bottom of meniscus

Question 3

Erlenmeyer Flask

Answer 3

Conical flask with narrow necks and wider base. For mixing, heating and stirring solutions. Not accurate for measuring volumes. Preferred over beaker for mixing because it minimizes risk of spilling and splashing. Used during titrations.

Question 4

Volumetric flask

Answer 4

Round flask with a flat bottom. Long and narrow neck. Used to reach specific volume of liquid, indicated by small marking on the neck. Often closed by cap to prevent evaporation and allow for vigorous shaking. Used for preparing or diluting a chemical solution.

Question 5

Boiling flasks

Answer 5

Round bottoms, long neck. Used to swirl and heat

liquids. Clamp required to keep it in position. They cannot be used to measure the volumes of liquids.

Question 6

Pipettes

Answer 6

Can be graduated or electronic. The most precise glassware for measuring the volume of a liquid. Variety of sizes. Used to transfer a specific volume of liquid to a container.

Question 7

Burets

Answer 7

Highly accurate. Used to dispense highly accurate volumes of liquid. In titrations, used to deliver a titrant to a solution. Long, graduated glass tubes with a very narrow opening at the bottom. Stopcock is positioned right
above the opening and is used to control the amount of liquid released.

Question 8

Test tubes

Answer 8

Glass tubes with one open end and a round, closed end. Holds small volumes of samples and can be used for mixing. Used to compare different samples qualitatively. Can be heated and cooled or used to store a
solution over a period of time. The open end can be capped.

Question 9

Droppers

Answer 9

Small glass tubes with rubber bulb on one end. Used to deliver a liquid (usually an indicator), in a drop-wise fashion.

Question 10

Bunsen burners

Answer 10

Metallic apparatus that produce an open flame for heating purposes. Connected to natural gas source by rubber tubing and have a valve that controls gas flow, and a collar that can be rotated to adjust airflow. Amount of gas provided to Bunsen burner is related to size of the flame. Light the Bunsen burner with a striker to ignite the flame.

Question 11

pH meter

Answer 11

Accurately measure pH of a solution. Can be used in acid-base titrations. Should always be calibrated prior to use.

Question 12

Digital balance

Answer 12

Accurate mass measurements

Question 13

Volumetric

Answer 13

Glassware that has a single marking that indicates a

specific volume. These are generally more precise than graduated glassware.

Question 14

Graduated

Answer 14

Any glassware that has several markings indicating different volume levels.

Question 15

Order of precision from most precise to the least precise

Answer 15

Pipettes > Burets/Volumetric Flasks > Graduated Cylinders > Beakers/Erlenmeyer Flasks

Question 16

Measuring the mass of a sample

Answer 16

First, tare the weighing paper or glassware that the sample will be placed on, before adding the sample and weighing on a digital balance.

Question 17

Titration

Answer 17

Delivers drop-by-drop volumes of a titrant to another solution
through a buret. Measures the volume of titrant needed to react completely with the other reagent.

Indicators that are known to change colour near an equivalence point of a
given reaction are added to solution to mark the end of the titration. The pH of a solution can also be observed throughout the titration to look for large jumps in pH and
for periods of stabilization (buffer zones).

Question 18

Equivalence point

Answer 18

The point at which the added titrant has completely reacted

with the reagent

Question 19

Endpoint

Answer 19

Point at which an observable property (e.g. colour change) occurs and this is associated with either being at or near the equivalence point.

Question 20

Titration error

Answer 20

Any deviation of the endpoint from the equivalence point

Question 21

Centrifugation

Answer 21

Centrifuge instrument separates different parts of a mixture. Spins mixture at very high speeds. Centrifugal force acts upon heavier components of the mixture (solids), such that they move towards the bottom of the vessel and form the pellet. After centrifugation has finished, we separate the liquid supernatant from the solid pellet by using either a pipette, decanting the liquid or filtration. Simple decantation involves pouring the liquid out of the original vessel, leaving the solid behind.

Question 22

Calorimetry

Answer 22

Measures amount of heat
energy released or absorbed during a chemical reaction. The change in heat can determine if reaction is exothermic or endothermic.

Question 23

Systematic errors

Answer 23

Consistent shifts in one direction of a measurement that result from faulty equipment or an error in
the procedure

Question 24

Random error

Answer 24

Errors not consistent but can vary in either direction. Result of human error

Question 25

Percent error of an experimentally derived value and a known literature value

Answer 25

| [(experimental - actual)/actual] | * 100%

Question 26

Safety Shower

Answer 26

Delivers a continuous stream of water to any student who has been extensively splashed with toxic or corrosive chemicals. This can also be used on students whose clothing may have caught on fire.

Question 27

Eye Wash Station

Answer 27

Treat any splashes of chemicals (acid, base, etc.) in or near the eyes. Thoroughly rinse the eyes by keeping both of your eyes open.

Question 28

Fume Hood

Answer 28

Provide proper ventilation in an enclosed space such that it minimizes exposure to harmful vapors or fumes from any volatile substances you may be working with. Cover any containers containing volatile substances with a watch glass, when not in use.

Question 29

Fire Extinguishers

Answer 29

Aim at the base of the fire. Position yourself in between the fire and the exit. Should only be used for solvent or electrical fires and not those resulting from paper or wood.

Question 30

Lab Coats

Answer 30

Always worn during the laboratory. If you get chemicals on your skin, rinse with lots of water and seek medical attention if needed. Wear closed-toe shoes.

Question 31

Safety Goggles

Answer 31

Always worn during the laboratory. Avoid wearing eye contacts in the lab, as dangerous fumes can concentrate under the contacts and cause complications.

Question 32

Rubber or Disposable Gloves

Answer 32

Should be worn when dealing with any potentially harmful chemicals

Question 33

Broken Glass Container

Answer 33

Broken glass should be cleaned up as soon as possible, with caution, using a dustpan

Question 34

Disposal of Solutions

Answer 34

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.