UCI Chem 1LD Practical

What factors determines whether a solute will dissolve in a solvent?

imf's, molecular dipoles, molecular geometry, electrostatic attraction

What is the strongest imf that must be overcome when melting menthol?

hydrogen bonding

A solution is created when a small amount of solute dissolves in a large amount of _________

solvent

What is concentration of a solvent reported as?

molality

A solutions concentration is reported as _______ per ________

solute per kilogram

What should you do to respond to an emergency?

know where the stairwells are, all laboratories must have two exits, stay calm, turn off lab equipment before leaving lab for a fire alarm

True or false: cinnamic acid dissolves in melted menthol

true

True or false: cinnamic acid does not stay dissolved in solid menthol

true

How will a weak acidity affect the freezing point depression?

The solution freezing point is lower than it should be

Why is the solution freezing point lower due to a weak acidity?

particles in the solution are greater due to dissociation

name common household products that contain flammable chemicals

rubbing alcohol, gasoline, antifreeze, nail polish remover

ways to stop a fire

place beaker over an open flame, ground metal container to prevent static electricity, remove ignition sources, limit quantities of flammable substances in work area

what is true about flammability?

1. inflammable is another word for flammable

2. a fire cannot start above or below a vapor's flammability limits

what number means that a chemical is extremely flammable?

4

The National Fire Protection Association (NFPA) diamond has a

_________ section for flammability

red

If the number _____________

appears in this section, the chemical is a combustible, it will catch fire

when heated.

2

The Global Harmonized System (GHS) symbol is a picture of a ___________

fire

If the hazard category is

_____________ , the chemical is extremely flammable

HC 1

If the hazard category is __________ , the chemical is a

combustible.

HC 4

best piece of glassware for TLC eluent ratios is __________

graduated cylinder

What is true about fume hoods

1. room air should be drawn into the fume hood

2. The window on the front of the fume hood is called a sash.

3. All work should be done at least 6 inches inside the hood.

4. A tissue paper held at the bottom of a sash should blow into the hood.

PEL

permissible exposure limit

odor threshold

gas concentration that 50% of the population can detect

odor fatigue

decreased sensitivity to odors after prolonged exposure

IDLH

Immediately Dangerous to Life and Health

OEL

Occupational Exposure Limit

what is the major underlying principle of chromatography?

separation will be achieved if one component adheres to the stationary phase more than the other component does

what is a stationary phase?

Where the molecules can't move. It is a solid or a really thick liquid

what is a mobile phase

Where the molecules can move. This is always a liquid or a gas

Why does most of the TLC plate turn pink?

unreacted permanganate is pink

Why does TLC spots turn yellow?

the compound has double bonds

What is true about gloves?

1. gloves should not be removed when they come in contact with hazardous chemicals

2. no glove material protects against all chemicals

permeation

the movement of a chemical through a surface or, on a molecular level, through intact materials; penetration, or spreading.

degradation

the process by which a chemical substance is broken down to smaller molecules by biotic means

breakthrough time

Time required for a chemical to permeate the material of a protective suit.

rate of transfer

speed at which chemical seeps through

True or false: nitrile gloves protect well against an aliphatic hydrocarbons like heptane and limonene

true

true or false: nitrile gloves can be degraded by acetone (a ketone)

true

What of the following guidelines should be followed to protect your skin in the chemical laboratory?

1. wear a lab coat

2. wear clothing that covers most of your body

3. wear sturdy closed toed and heel shoes

4. use gloves when appropriate to do so.

toxicology

the study of the adverse effects of chemicals or physical agents on living organisms

toxicity

the ability of a chemical to cause harm to an organism

toxicant

A chemical with adverse human health effects

toxin

toxic substance made by living organisms

acute toxicity

the ability of a chemical to cause harm to an organism with only one exposure

chronic toxicity

the ability of a chemical to cause harm to an organism only after the chemical accumulates to a specific level after many exposures over time

LD(50)

lethal dose (of a toxin) for 50% of the test population

LC(50)

Lethal Concentration 50%, the concentration which kills 50% of the tested animals

what factors influence toxicity

dose, age, and animal models are not always a good representation of human responses

Acetaminophen/s fate in the human body

metabolizes and removing water soluble compounds

DDT effect on the human body

bioaccumulation -organism absorbs a substance faster than it can be lost or eliminated

ethylene glycol effect on the human body

breaks down into toxic compounds in the body

sensitizer

formaldehyde

asphyxiant

carbon monoxide

teratogen

acrylonitrile

carcinogen

benzene

organ toxicant

ethanol

neurotoxin

acetone

poison

cyanide

what assumptions can be made if the solid does not melt in the digi-melt?

digi-melt does not reach high enough temps to melt the solid or it is broken

what is the role of the chemical? vanillin

limiting reagent

what is the role of the chemical? acetic acid

source of H+ for redox balance

what is the role of the chemical? hydrogen peroxide

oxidizing agent

what is the role of the chemical? horseradish peroxidase

catalyst

hazard

A potential source of danger

risk

the probability that a hazard will cause a harmful response

risk level

hazard severity x exposure probability

risk assessment

the process of measuring risk (PPE)

What affects the probability of a lab accident

how other people behave, how chemicals are used, how the physical environment is controlled

how to reduce the probability of exposure to a hazard

1. amt of chemicals used

2. type of PPE needed

3. routes of exposure

4. containment of chemicals

5. knowledge of the hazards

what determines the severity of a hazard?

1. GHS symbols

2. chemical amt used

3. PELs

4. ld 50 values

5. NFPA fire ratings

zero risk

no hazards are present

eye hazard

causes irreversible damage to eyes

sensitizers

cause hypersensitivity to lungs or skin

mutagens

produce genetic defects

carcinogens

substances that cause cancer

reproductive toxins

cause birth defects

target organ toxicants

cause damage to certain organs

aspiration hazards

can be fatal if swallowed or inhaled

acute toxicants

Are fatal if exposed to small amounts

corrosives

cause severe skin burns

what makes good sunscreen

1. high percent yield

2. broad absorbance of uv light

3. low hazard starting materials

4. melting point values

4. ambient reaction conditions

5. color and feel

green chemistry

uses materials and processes that are intended to prevent or reduce pollution at its source

what applies to green chemistry

1. high yield reactions

2. methods used to eliminate hazards during use and manufacturing

3. 3. use less hazardous reagents

4. choose reactions that can be done at room temp and pressure

5. recycle reagents and solvents

Why does 1LD use green chemistry

1. using starting reagents from renewable feedstocks

2. sunscreen synthesis did not require heat