Laboratory Equipment

Question 1

Where must you keep explosive chemicals that require cooler temperatures in a lab?

Answer 1

Lab fridges encased with metal housing and with wiring and controls outside the chamber.

Question 2

How do you maintain the lab fridges?

Answer 2

Frequent temperature checks, cleaning, defrosting, checking door gasket for mold and proper sealing, and vacuum condenser.

Question 3

What is the standard fridge temperature?

Answer 3

4c

Question 4

What is the lab freezer temperature?

Answer 4

-70c and -20c

Question 5

What do water baths do?

Answer 5

They provide constant temperature by circulating convention currents.

Question 6

What are water-jacketed incubators?

Answer 6

More evenly distributed heat and rapid temperature recovery due to convention air flow

Question 7

What is the difference between an oven and an incubator?

Answer 7

Ovens have higher temperatures

Question 8

What are biological safety cabinets (BSC)?

Answer 8

Workspace that prevents exposure to infectious aerosols

Question 9

How do BSC work?

Answer 9

HEPA filters filter out microbes

Question 10

What does HEPA stand for?

Answer 10

High Efficiency Particulate Air

Question 11

What is the standard efficiency of a HEPA filter?

Answer 11

Removing particles 0.3 um in size

Question 12

What are HEPA filters made of?

Answer 12

Pleated glass and paper

Question 13

What are UV light used for?

Answer 13

It disinfects air and contaminated surfaces that can’t be reached by disinfectants

Question 14

What is an example of a biological safety cabinet class II?

Answer 14

Laminar flow safety cabinet

Question 15

Laminar flow safety cabinet is the most commonly used for handling infectious material. (T/F)

Answer 15

True

Question 16

How does the laminar flow safety cabinet work?

Answer 16

Air flow that protect the surface from airborne microorganisms and prevents infectious organisms from escaping

Question 17

What are fume hoods used for?

Answer 17

Chemical labs to draw away dangerous fumes, gases or vapours

Question 18

How long do you turn on the air before and after using the fume hood?

Answer 18

15 minutes

Question 19

What is a centrifuge for?

Answer 19

To separate substances by accelerating gravity

Question 20

What is RCF?

Answer 20

Relative centrifugal force

Question 21

What is RCF describing?

Answer 21

The force required to separate two phases

Question 22

What is the unit for RCF?

Answer 22

G forces (g) - the number of times greater than the force of gravity

Question 23

What is the formula for RCF?

Answer 23

RCF = Krn^2

Question 24

What is the value of K in the RCF formula?

Answer 24

K = 1.118 x 10^-5 (when r is in cm)

Question 25

How is the radius (r) measured for RCF?

Answer 25

From the centre of the rotation to the bottom of the tube

Question 26

What is the n in the RCF formula?

Answer 26

It is the speed of rotation of the rotor in rpm.

Question 27

What is the most effective way to increase RCF?

Answer 27

Increasing rpm

Question 28

Where is the maximum RCF?

Answer 28

The force at the bottom of the tube

Question 29

Where is the minimum RCF?

Answer 29

The force at the surface of the liquid

Question 30

What is a device that can be used to determine RCF?

Answer 30

Nomograph

Question 31

What influences the time required to separate mixtures of different densities?

Answer 31

- rotor speed - radius of the rotor - depth of liquid in the tube

Question 32

What decreases the time needed to centrifuge?

Answer 32

- if you increase the speed or the radius | - if you decrease the depth do the liquid

Question 33

What’s the difference between the centrifuge requirements for serum/plasma samples and urine samples?

Answer 33

Serum/plasma need to be spun at higher RCF for longer to make sure the cells are spun to the bottom. Urine samples are centrifuged are a lower RCF for less time to make sure cell components are intact for microscopy.

Question 34

What does pivotal axis mean?

Answer 34

It is the line across the two points of the trunnion rings that allow the bucket to swing.

Question 35

What’s the main hazard associated with the use of a centrifuge?

Answer 35

Dispersion of aerosols

Question 36

What helps control aerosol dispersions in a centrifuge?

Answer 36

- sealed dome shields - safety trunnion cups - auto locks

Question 37

What do electronic balances use to counter balance the load?

Answer 37

Electromagnetic force

Question 38

How does an electrical balance work?

Answer 38

The pan is connected to a coil that a current goes through. The weight of the load is determined by the voltage of the current as it is proportional to the weight of the load.

Question 39

What are top load balances used for?

Answer 39

Preparation of reagents, stains and less accurate work

Question 40

What’s the difference between top load balances and analytical balances?

Answer 40

Top loads weighs to 2 decimal places while analytical weighs to 4 decimal places

Question 41

What does pH stand for?

Answer 41

Potential hydrogen

Question 42

What does pH meters measure?

Answer 42

The hydrogen ion concentration in a solution

Question 43

When do solutions have higher pH?

Answer 43

When they contain less H+ ions

Question 44

What is a combination electrode?

Answer 44

Reference electrode + indicator electrode

Question 45

What is the definition of potential?

Answer 45

It’s the difference in charge separated by a barrier

Question 46

What does the reference electrode do?

Answer 46

It produces a constant potential by releasing a gradual flow of KCl, by the porous plug, into the solution

Question 47

How does the indicator electrode work?

Answer 47

The glass surrounding it attracts H+ ions. If the number of hydrogen ions in the solution is different than the number of hydrogen ions on the inside of the indicator, a potential charge is produced.

Question 48

How is pH determined by the pH meter?

Answer 48

It is the difference between the potential produced by the indicator electrode and the constant potential at reference electrode.

Question 49

What is the standardized temperature for pH meters?

Answer 49

25c

Question 50

What does the thermometer got to do with pH?

Answer 50

It enables adjusts for changes to hydrogen ion activity due to temp changes

Question 51

_ H+ = _ pH = acids

Answer 51

⬆️ H+ = ⬇️ pH = acids

Question 52

_ H+ = _ pH = bases

Answer 52

⬇️ H+ = ⬆️ pH = bases

Question 53

What is the appropriate solution to soak pH meters for protein?

Answer 53

1% pepsin/0.1 M HCl for 15 minutes

Question 54

What is the appropriate solution to soak pH meters for inorganic deposits?

Answer 54

0.1 EDTA for 15 minutes

Question 55

What is the appropriate solution to soak pH meters for grease?

Answer 55

Detergent or ethanol