Module # 1

Question 1

Tolerance/Accuracy

Answer 1

Refers to the limits of error or the nearness to the true value (e.g. 5mL +/- 0.005 = 4.995-5.005)

Question 2

Precision or Reproducibility

Answer 2

Refers to the ability to repeatedly produce the same value.

Question 3

Capacity

Answer 3

Refers to the volume which the glassware will hold or deliver.

Question 4

Temperature

Answer 4

Refers to the temperature at which the glassware was calibrated and is to be used. Most glassware is calibrated to 20 degrees Celsius. Liquids must be able to reach room temperature before being measured. Water expands when warmed. (The reading will read more if cold solution is used.)

Question 5

TC

Answer 5

Means “to contain” This glassware has been calibrated to hold the stated volume. When the liquid is drained, less than the stated volume will be delivered because some of the liquid adheres to the walls. A graduated cylinder is an example.

Question 6

TD

Answer 6

Means “to deliver” When the liquid is drained from the container, the exact volume will be delivered because it was calibrated to allow for the liquid to adhere to the walls.

Question 7

Meniscus

Answer 7

Surface tension draws up the edges of the liquid. The meniscus should be adjusted so that the lowest part of the meniscus is directly on the calibration mark.

Question 8

Labeling reagents

Answer 8

Label all reagents with the date and your initials (i.e. JMG, 2015/09/09.)

Question 9

Volumetric pipette

Answer 9

These pipettes are used for accurate measurement of aqueous fluids.

Question 10

Mohr pipette

Answer 10

Comes in sizes ranging from 0.1 mL to 25mL. It saves on time when pipetting the same solution to multiple tubes.

Question 11

Serological Pipette

Answer 11

Not suitable for analytical work, Fills and drains fast. Do not get fluid in the bulb. Two etched rings at top indicate serological pipette. Used sometimes in microbiology where accuracy is not required.

Question 12

MLA pipette

Answer 12

These pipettes come in a variety of sizes and may be single-volume or adjustable volume. Disposable plastic tips.

Question 13

Eppendorf/Hamilton

Answer 13

Are similar to MLA except that the plunger has two stops. The first stop is to pick up the liquid. Then two stops to dispense the liquid. Remember to hold the plunger down until you have exited the test tube. Has disposable plastic tips.

Question 14

Pasteur pipette

Answer 14

Pasteur pipettes are frequently used in the lab. They may be made of glass or plastic. NOT for accurate pipetting.

Question 15

Contrad 30, Extran 30 and Pyroneg powder

Answer 15

Used to clean glassware.

Question 16

Volumetric flasks

Answer 16

Used primarily in the preparation of accurate solutions. They are calibrated TC at 20 degrees celsius.

Question 17

Cylinders

Answer 17

Are much less accurate than volumetric flasks and are used to prepare solutions that do not require a high degree of accuracy.

Question 18

Beakers

Answer 18

Containers for reagents or water.

Question 19

Erlenmeyer flasks

Answer 19

May be used as containers during the preparations of some solutions.

Question 20

Test tubes

Answer 20

May be glass, plastic, plain, centrifuge, comes in a variety of sizes. We commonly use 12 x 75 and 16 x 100mL

Question 21

Reagent bottles

Answer 21

May be glass, plastic, clear or amber.

Question 22

Centrifuges

Answer 22

Used to accelerate the gravitational separation of substances (liquid/solid mixtures such as blood.)

Question 23

Relative Centrifugal Force

Answer 23

Is used to describe the force required to separate two phases. RCF = Krn^2

Question 24

Tachometer

Answer 24

Indicates the speed of the rotor in revolutions per minute (rpm) of a centrifuge.

Question 25

Trunnion rings

Answer 25

Hold the buckets in the head of the centrifuge.

Question 26

Airfuge

Answer 26

A type of centrifuge that spins at 90,000 rpms

Question 27

Bench top

Answer 27

A type of centrifuge

Question 28

Floor

Answer 28

Large capacity centrifuge

Question 29

Refrigerated or heated

Answer 29

A centrifuge for temperature sensitive procedures.

Question 30

Balancing like tubes

Answer 30

Same size, volume and stoppers in balanced proportion within a centrifuge.

Question 31

Glutaraldehyde

Answer 31

A soak used to clean a centrifuge if tubes have exploded inside.

Question 32

Routine maintenance of a centrifuge

Answer 32

Clean with a non-corrosive disinfectant, Inspect brushes and replace when worn, Inspect for corrosion crack in the metal.

Question 33

Electronic balances

Answer 33

Use an electromagnetic force to counter balance the load placed on the pan. The pan is attached to a coil directly suspended in the field of a permanent magnet.

Question 34

Tare correction

Answer 34

Alows for the subtraction of the empty container weight since you only want the weight to represent the substance. After the container is placed on the pan, it is tared, meaning the scale will return to zero.

Question 35

NBS: National Bureau Standards

Answer 35

Weights that are used to calibrate balances. If the weights measured are not accurate, then the balance needs servicing!

Question 36

Incubators

Answer 36

May be anhydride or water jacketed. Water jacketed incubators allow for more even heat distribution and rapid temperature recovery when the door is opened. Periodic cleaning and frequent temperature checks are required for maintenance.

Question 37

Ovens

Answer 37

Are the same as incubators except that the temperature is higher.

Question 38

Water baths/heating blocks

Answer 38

The water bath has circulating water that heats the sample by water convection currents. Frequent changing of the water is needed. Heating blocks provide a more even temperature.

Question 39

Refrigerators and freezers

Answer 39

Standard refrigerator temperature is 4 degrees celsius. Freezers can be set to between -20 and -70 degrees celsius. Proper gloves must be worn.

Question 40

Compressed gas

Answer 40

Can be hazardous, regardless of the type of gas. If the valve is broken or bent off the tank a leak can develop in some way.

Question 41

When transporting compressed gas tanks:

Answer 41

Remove the regulator and put on the protection cap, use a trolley with a safety strap, Do not allow tanks to strike each other.

Question 42

When hooking up a gas cylinder.

Answer 42

Strap it securely to the counter, be sure the regulator is the correct one for the gas being used, be sure all the connections are tight, never oil or grease valves, gauges or regulators.