REAGENT PREPARATION Flashcards
Solution
Mixture of substances
Solute
Substance that dissolves
Solvent
Substance that dissolves solute
- usually water
Dilute solutions
Has small portion of solute in solution
Concentrated solutions
Contains large portion of solute in solution
Diluent
Agent that dilutes a fluid
Dilution
Adding diluent to change a concentration of a solution to a lower concentration
What is the most common solvent in clinical labs?
water
What water purity has the best quality (minimum impurities)?
Type I
What type of water is used to prepare for chemical testing, preparation of reagents, and controls?
Type I
What water purity is “good” quality and used for preparing solutions?
Type II
What type of water purity has the lowest quality?
Type III
How is type I and type II water?
Type III water
How is the purity of water determined?
The amount of electrical resistance
How is water purity measured?
Mega ohms
What type of water has higher electrical resistance and why?
Water that is purer as it has less dissolved particles.
What is the five steps of water purification?
- Distillation
- Deionization
- Reverse osmosis
- Carbon absorption
- Filtration
What grade of chemicals have the highest purity?
Analytical and reagent
Commercial grade chemicals have ___ degree of impurities.
High
What is the procedure that’s “diluting up to the final volume”?
% weight per volume
What procedure is referred to as “diluting to volume”?
% volume per volume
What is Avogadro’s number?
6.022 x 10^23
How do you find molarity of a solution?
It’s then # of mols of solute per litre of solution (mol/L = M)
What is normality?
It is the unit of concentration describing acids and bases; number of moles equivalent to hydrogen or hydroxide ion per litre of solution
Caustic reagent is added TO the water. (T/F)
True
WHMIS is just provincially legislated. (T/F)
False — also federally legislated
What is the four primary components of WHMIS?
- Hazard identification and classification
- Safety data sheet (SDS)
- Labelling
- Worker education
What are the two hazard groups that classifies hazardous substances?
Physical hazards and health hazards
Hazard categories are numbered from 1 to 4. Which is the least and which is the most hazardous?
1 = most 4 = least
How many classes are within the physical hazard group?
19 classes
How many classes are within the health hazard group?
12 classes
What are some examples of what’s considered a health hazard effect?
Skin irritation, carcinogenicity and toxicity
What are examples of effects of physical and chemical properties?
Flammability and reactivity
What 16 headings are included in the SDS?
Identification, hazard identification, composition, first aid measures, fire fighting measures, accidental release measures, handling and storage, exposure control/personal protection, physical and chemical properties, stability and reactivity, toxicological info, *ecological info, *disposal considerations, *transport info, *regulatory info, *other info
What is found on supplier labels?
- Product identifier
- Pictogram
- Signal word (danger or warning)
- Hazard statements (fatal, toxic, harmful)
- Precautionary statements
- Supplier identifier
When is a complete workplace label not required?
*but labeling of the container being use is a must
- product poured into a container for immediate use
- product is in the control of the person who aliquoted it
What is needed on a workplace label at SAIT?
Concentration of the product (matching SDS name)
PPE instructions + pictogram
SDS available
Who and when was it prepared
How do you properly transport compressed gas?
- removing the regulator and putting on the protection cap
- use of a trolley and safety straps
- no striking of tanks
What is the flammability range?
Range of vapour concentration per amount of air which the mixture will burn
How is the flammability range expressed?
Vapour concentration/O2 concentration
If a mixture is “too rich”, why will it not burn?
Because the concentration of oxygen is too low, therefore, it won’t ignite
What is a flash point?
the lowest temperature at which liquid gives off vapour near the surface to form a flammable mixture with the air
lower the flash point, the ____ the danger
greater
what is the flash point for ether?
-45c
what is the flash point for acetone?
-20c
what is the flash point of toluene?
-4c
what is the flash point of alcohol?
+12c
what is the flash point of xylol?
+25c
What kind of fire extinguishers do you use for flammable liquids?
extinguished with a CO2 or ABC fire extinguisher
What are some examples of acids that are corrosive?
- hydrochloric acid (HCl)
- sulfuric acid (H2SO4)
- nitric acid (HNO3)
- glacial acetic acid (CH3COOH)
What are some examples of bases?
- sodium hydroxide (NaOH)
- Potassium hydroxide (KOH)
- ammonium hydroxide (NH4OH)
- sodium hypochlorite (NaClO)
What’s the difference between LD50 and LC50?
LD50 = dose = quantity of the substance expected to cause death
LC50 = concentration = concentration of substance in air that when inhaled over a period of time to cause death of 50% of an animal population
What is LD50 measured in? LC50?
LD = mg (or g) per kg of animal body weight LC = units of parts per million or mg/M^3
How can toxic substances enter the body?
- inhalation, ingestion and absorption through the skin
What does threshold limit value (TLV) and permissible exposure limit (PEL) mean?
it indicates the maximum limit of exposure to an air contaminant
What are the three ways that TLV/PEL can be expressed?
- 8-hour TWA (time-weighted average)
- STEL (short term exposure limit)
- Ceiling limit
Risk of handling chemicals _____ to the length and frequency of exposure as well as the concentration of the chemical.
proportional
What does 8-hour TWA indicate?
average concentration over 8 hours and its condition to show that worker are exposed repeatedly to these environments without adverse health effects
What does STEL indicate?
the max concentration that workers can be exposed to something for up to 15 minutes without adverse health effects
What does ceiling limit indicate?
concentration of airborne substances that can’t be exceeded
- applied to many chemicals with acute toxic effects
how is hydrocyanic acid vapours formed?
by mixing solutions that contain cyanide with acids
What are the four chemicals commonly used in a lab?
- acetone
- formaldehyde
- methanol
- xylene
