Safety, Lab Equipment, Units and Dilutions

Question 1

What are the three basic units of measurement for length, weight and volume in the SI system?

Answer 1

Length = meter (m)
Mass = gram (g)
Volume = litre (L)

Question 2

What do you do to get a deci (d) from 1 unit?

Answer 2

Times by 10. A deci (d) is 1/10 of 1 unit.

Question 3

How many centimeters (cm) in a meter(m)?

Answer 3

Times by 100. A centi (c) is 1/100 of 1 unit. (Or move decimal to the right two places).

Question 4

What are the seven units of the SI system?

Answer 4

Meter for length
Kilogram for mas
Mole for concentration
Second for time
Ampere for electric current
Kelvin for temperature
Candela for light intensity

Question 5

What is the formula for molarity?

Answer 5

Molarity or moles/liter =

(gram/gram molecular weight) / 1L

Question 6

What are the two parts to a dilution?

Answer 6

1. The sample that is to be diluted.

2. The diluent used to perform the dilution, e.g. water.

Question 7

What are the two parts to a solution?

Answer 7

1. A solute, which is the part being placed into the solution.
2. The solvent - the liquid which the solute is being diluted into.

Question 8

What is a general description of a dilution?

Answer 8

Weaker solution is made from a more concentrated solution.

Question 9

What is the equation for dilution ratio?

Answer 9

Dilution Ratio = Vs / (Vs + Vd)
where
Vs = volume of substance being diluted and
Vd = volume of diluent

Question 10

How is a dilution ratio typically expressed?

Answer 10

It is expressed in a ratio of lowest terms. Expressed as the ratio of 1 to a number. The numerator needs to be 1.

Question 11

What is the formula for concentrations of dilutions?

Answer 11

Original Concentration x Dilution Ratio = New Concentration

Question 12

What terms or units and concentrations be described as?

Answer 12

Concentrations can be in %, g/L (weight per volume), M (molarity), or N (normality).

Question 13

What are beakers typically used for in a med lab?

Name some characteristics

Answer 13

General reagent prep
Allows a lot of evaporation
Markings are approximate
Can heat
Cannot use to measure with any degree of accuracy

Question 14

What are graduated cylinders used for?

Accuracy?

Answer 14

Measure volume of liquids.

Not as accurate as volumetric flask.

Question 15

What are Erlenmeyer flasks used for?

Answer 15

General preparation and mixing of reagents
Good for boiling or heating (less evaporation)
Not used for critical measurements. Accuracy is similar to beaker (lines are approximate).

Question 16

What are Volumetric Flasks used for?

Answer 16

Measures exact volume if meniscus is at the line.
Most accurate.
Used if measurement is critical.

Question 17

What are funnels used for?

Answer 17

Aids in getting chemicals or liquids in flasks or storage bottles.
Can use with filter paper.

Question 18

What are burets and clamps used for?

Answer 18

Glass tube (buret) with a valve near one end that deliveries known volumes of liquid. The clamp holds the buret in place. Flow of liquid is controlled by the valve. Used for analytical chemistry.

Question 19

What a scoopulas used for?

Answer 19

Used to transfer dry chemicals usually to a weigh boat for weighing

Question 20

What is a mortar and pestle used for?

Answer 20

Used to grind up dry chemicals, pills, or crystals to be dissolved

Question 21

What is a transfer pipette used for?

Answer 21

Pasteur pipettes or transfer pipettes used frequently in labs

Can be made of either plastic or glass

Used to transfer liquid from one container or tube to another

Question 22

What’s a bulb or pi pump used for?

Answer 22

Used to aspirate (draw up) liquid into macro pipettes.

Question 23

What are storage bottles used for and made of?

Answer 23

Can be used to store chemicals or to discard particular chemicals that are volatile.
Made of glass or plastic.

Question 24

What are four types of glass materials used in the lab?

Answer 24

Flint glass
Borosilicate
Quartz glass
Low actinic glass

Question 25

What are characteristics of flint glass?

Answer 25

inexpensive | low resistance to heat and chemicals

Question 26

What are characteristics of borosilicate glass?

Answer 26

Nonreactive with most chemicals. High thermal resistance. Eg. Pyrex and Kimax.

Question 27

What are characteristics of quartz glass?

Answer 27

Expensive High silica content Has excellent light transmission without distortion (good for cuvettes)

Question 28

What are characteristics of low actinic glass?

Answer 28

Amber/Brown in colour | Helps protect light sensitive chemicals

Question 29

What are types of plasticware used?

Answer 29

Polyethylene – can be clear, cheap, very common Polypropylene - milky or opaque, heat resistant, can be autoclaved Polystyrene – clear, rigid All are lightweight, impact resistant, corrosion resistant. Teflon – white, stopcocks in burets

Question 30

What are transfer pipettes used for?

Answer 30

Frequently used in labs to transfer liquid from one container to the other.

Question 31

What are conical centrifuge tubes used for?

Answer 31

Used to spin fluids (microbiology) in a centrifuge – for example knee fluids or abdominal fluids

Question 32

What are stir bars or magnetic stirrers with retriever used for?

Answer 32

Stirring chemicals.

Question 33

What can be used to heat and evaporate liquid to hydrate it out?

Answer 33

Evaporating dish.

Question 34

What is a MacBick bottle used for?

Answer 34

Used in Microbiology lab to sterilize media. Cap on bottle is designed that it can be autoclavable, steam goes in..

Question 35

What is a fleaker?

Answer 35

Combination flask and beaker Not for critical measurements Has a lid

Question 36

What are methods to clean glassware?

Answer 36

May have to autoclave or clean with bleach Detergent – scrub (we use sparkleen) Tap water Distilled water rinse x 3 Dry in oven or leave on rack to air dry

Question 37

What safety precautions need to be taken with glass?

Answer 37

``` Precautions: Inspect for chips and cracks If breakage clean with dustpan and broom Use borosilicate when heating When inserting glass tubing: Lubricate Wrap glass in towel so it doesn’t crack Hold 1” to 2” from end Gently twist into stopper ```

Question 38

What are mixers, blenders used for?

Answer 38

Usually used to mix media or microorganisms in saline to make a suspension Precautions: Greatest danger is aerosols So operate inside BSC, wait one min before opening lids, if open use a towel soaked in disinfectant and disinfect surfaces after used.

Question 39

What are some precautions for microscopes?

Answer 39

Inspect electrical cords regularly Disinfect regularly Slides not fixed are considered infectious Set up station ergonomically

Question 40

What are some precautions for automated equipment?

Answer 40

``` Only fix if you are authorized Store reagents correctly Visually inspect tubing and connections Use safety shield in front of sampling probe Wear gloves Disinfect lines Verify waste line discharges meet regulations Avoid over-filling sample cups Disinfect prior to servicing ```

Question 41

What are the hazards and precautions for cryostats?

Answer 41

``` Hazards: Physical (temperature, cuts) Biological Precautions: Keep cover closed when cutting Wear gloves and mask (can inhale dust) Routinely decontaminate parts Routine = 70 - 100% Ethanol Suspected TB = tuberculosis disinfectant Creutzfeldt-Jakob Disease = sodium hydroxide Defrost weekly For STAT tissues (i.e. need results ASAP, and microtome inside so lock handle when not in use). ```

Question 42

What are some precautions for electrophoresis apparatus?

Answer 42

``` Inspect electrical components regularly Verify integrity of tank Locate away from high traffic areas Display proper signs “High Voltage” (Used for eletrophoresis during molecular .....) ```

Question 43

What are some precautions for a chemical fume hood?

Answer 43

``` Evaluate prior to use for adequate face velocity Hoods should be left on at all times Have sash at appropriate height Keep sash clean NEVER store chemicals in hood Avoid sudden movements Should have an audible alarm ```

Question 44

True or False. A chemical fume hood and a biological safety cabinet is essential the same thing.

Answer 44

False. A chemical fume hood is used for chemicals and a Biological Safety Cabinet is used for biologicals.

Question 45

In what colour binder is the safe work practices in for all labs?

Answer 45

In all of the labs the Safe Work Practices binder is YELLOW.

Question 46

What is a centrifuge?

Answer 46

Rotates at a high speed around a central axis separating components of different densities contained in a liquid. Heavier substances go towards the bottom of the tube due to gravity.

Question 47

What is the formula for RCF (Relative Centrifugal Force)?

Answer 47

``` RCF = K x r x n^2, where K = 1.118 x 10^-5, r is radius from center in cm n is RPM ```

Question 48

Why do we need to calculate RCF?

Answer 48

To figure what speed and times the BD Vacutainer and Blood Collection tubes should be spun at. Example, BD Vacutainer spun at 1000 to 1300 RCF for 10 min in a swing bucket centrifuge.