UCI Chemistry 1LD Practical Study Set

Place the steps for doing a dilution with volumetric glassware in order:

A) Pre-rinse the volumetric pipet with small amounts of stock solution

B) Remove pipet from stock solution and touch hanging drops

C) Pre-rinse the volumetric flask with solvent

D) Fill the volumetric pipet above the calibration line

E) Remove the bulb and place a finger over the stem

F) Adjust pressure on the stem until liquid's meniscus is level to the calibration line

G) Place pipet into new vol flask and remove finger from pipet

H) Let pipet drain into vol flask

I) Fill vol flask to calibration line with solvent

J) Cap flask and invert to mix

C) Pre-rinse the volumetric flask with solvent

A) Pre-rinse the volumetric pipet with small amounts of stock solution

D) Fill the volumetric pipet above the calibration line

E) Remove the bulb and place a finger over the stem

F) Adjust pressure on the stem until liquid's meniscus is level to the calibration line

B) Remove pipet from stock solution and touch hanging drops

G) Place pipet into new vol flask and remove finger from pipet

H) Let pipet drain into vol flask

I) Fill vol flask to calibration line with solvent

J) Cap flask and invert to mix

What information should be recorded when using a balance?

a) Color

b) Number and manufacturer name

c) Scale

d) Type

b) Number and manufacturer name

What should be done to the weighing container before adding any chemicals?

a) Heat the weighing container

b) Pre-rinse the weighing container

c) Tare the weighing container

c) Tare the weighing container

What will cause the mass displayed on the digital scale to fluctuate?

a) If a nonvolatile liquid is being weighed

b) If the draft shields are closed

c) If the object being weighed is not at room temperature

c) If the object being weighed is not at room temperature

What must be done before leaving the balance area?

a) Clean up any spills

b) Discard used weighing paper

c) Both

c) Both

Lead(II) nitrate and potassium iodide are both semi-crystalline white solids that when dissolved in water forms a clear solutions. If these two solutions are combined, a banana yellow opaque mixture is created. The resulting solution is filtered to collect the banana yellow lead(II) iodide precipitate. The filtrate containing the potassium nitrate byproduct is a clear and colorless solution.

What Qualitative data is missing from the description?

a) clarity of reactants

b) clarity of products

c) color of reactants

d) color of products

e) crystallinity of reactants

f) crystallinity of products

a) clarity of reactants

f) crystallinity of products

Precision means that [A] measurements are close to [B]

[A]

A1) individual

A2) a few

A3) several

A4) the average value of

A5) all

[B]

B1) the accepted value

B2) the average value

B3) each other

B4) zero

Precision means that individual measurements are close to each other.

A1) individual

B3) each other

Accuracy means that [C] measurements are close to [D].

[C]

C1) individual

C2) a few

C3) several

C4) the average value of

C5) all

[D]

D1) the accepted value

D2) the average value

D3) each other

D4) zero

Accuracy means that individual measurements are close to the accepted value.

C1) individual

D1) the accepted value

Edward's data for the density of ethanol is 0.770, 0.791, 0.780. 0.795.

His average is 0.784

His data is

E1) accurate

E2) precise

E3) accurate and precise

E4) none

E1) Accurate

Fiona's data for the density of ethanol is 0.796, 0.798, 0.799. 0.797.

Her average is 0.798

Her data is

F1) accurate

F2) precise

F3) accurate and precise

F4) none

F2) precise

George's data for the density of ethanol is 0.788, 0.790, 0.787, 0.789

His average is 0.789

His data is

G1) accurate

G2) precise

G3) accurate and precise

G4) none

G3) accurate and precise

Percent error

A) = [Experimental value-Theoretical Value]/Theoretical value x 100

B) can be expressed with a sign to show direction of error

C) can only be calculated if the theoretical value is known

D) is similar to average deviation

E) quantifies the accuracy of a result

B) can be expressed with a sign to show direction of error

C) can only be calculated if the theoretical value is known

E) quantifies the accuracy of a result

Given: Mconc​ Vconc​ = Mdil​ Vdil​ and 50 mL of a ~6 M HCl(aq) from concentrated HCl

[A] What is Vconc?

A1) 1

A2) 5

A3) 10

A4) 25

A4) 25

Given: Mconc​ Vconc​ = Mdil​ Vdil​ and 50 mL of a ~6 M HCl(aq) from concentrated HCl

[B] What is Vdil?

50mL

Given: Mconc​ Vconc​ = Mdil​ Vdil​ and 50 mL of a ~6 M HCl(aq) from concentrated HCl

[C] What is Mconc?

11.6M

Given: Mconc​ Vconc​ = Mdil​ Vdil​ and 50 mL of a ~6 M HCl(aq) from concentrated HCl

[D] What is Mdil?

5.8M

11.6M x 25mL = Mdil x 50mL

11.6x25/50=5.8M

Given: Mconc​ Vconc​ = Mdil​ Vdil​ and 50 mL of a ~6 M HCl(aq) from concentrated HCl

[E] How is diluting acid different than diluting other solutions?

E1) Concentrated acid is placed in an empty vol flask then water is added

E2) the dilution is done first in a beaker

E3) water must be added to the flask before the concentrated acid

E3) water must be added to the flask before the concentrated acid

Mercury in its pure elemental form is a liquid with a density of 13.534 g/mL. How many moles are present in 3.69 μL?

0.000249mol

What is the theoretical yield of ammonia, NH3, (in grams) if 0.462 g of H2=​ was reacted with an excess of N2?

2.62

An aqueous solution was created by placing 0.0185 g of NaCl into a 50 mL volumetric flask and diluting to volume with deionized water. (Because the amount of solute is small, you may assume that the volume & density of the solution is equal to the volume & density of the solvent where appropriate.)

[A] Molarity?

0.00632

An aqueous solution was created by placing 0.0185 g of NaCl into a 50 mL volumetric flask and diluting to volume with deionized water. (Because the amount of solute is small, you may assume that the volume & density of the solution is equal to the volume & density of the solvent where appropriate.)

[B] Molality?

0.00632

An aqueous solution was created by placing 0.0185 g of NaCl into a 50 mL volumetric flask and diluting to volume with deionized water. (Because the amount of solute is small, you may assume that the volume & density of the solution is equal to the volume & density of the solvent where appropriate.)

[C] Mole fraction of NaCl?

0.000114

An aqueous solution was created by placing 0.0185 g of NaCl into a 50 mL volumetric flask and diluting to volume with deionized water. (Because the amount of solute is small, you may assume that the volume & density of the solution is equal to the volume & density of the solvent where appropriate.)

[D] Mass Percent of NaCl

0.0370

Order the steps for using an SDS:

a) Determine the hazard class

b) Compare label info to ensure you have the right SDS

c) Look at the procedures for safe handling

b) Compare label info to ensure you have the right SDS

a) Determine the hazard class

c) Look at the procedures for safe handling

Which option fits the best for the RAMP acronym?

R...

R1) Remember to wear goggles

R2) Review laboratory guidelines

R3) Recognize the hazard of acid to the eyes

R3) Recognize the hazard of acid to the eyes

Which option fits the best for the RAMP acronym?

A...

A1) Assess procedure, knowledge, and exposure probability

A2) Access the eyewash

A3) Allocate enough time

A1) Assess procedure, knowledge, and exposure probability

Which option fits the best for the RAMP acronym?

M...

M1) Maximize knowledge of the procedure

M2) Minimize risk of exposure by wearing goggles

M3) Moderate eye exposure with safety glasses

M2) Minimize risk of exposure by wearing goggles

Which option fits the best for the RAMP acronym?

P...

P1) Protect partner with goggles

P2) Prepare for hazards by finding references

P3) Prepare for emergencies by locating eye wash

P3) Prepare for emergencies by locating eye wash

Which chemical...

[A] destroys living tissue on contact?

A1) Corrosive

A2) Flammable

A3) Poison

A4) Irritant

A5) Oxidizer

A6) Toxic

A7) Sensitizer

A1) Corrosive

Which chemical...

[B] Easily ignites and burns rapidly?

B1) Corrosive

B2) Flammable

B3) Poison

B4) Irritant

B5) Oxidizer

B6) Toxic

B7) Sensitizer

B2) Flammable

Which chemical...

[C] irritates living tissue on contact?

C1) Corrosive

C2) Flammable

C3) Poison

C4) Irritant

C5) Oxidizer

C6) Toxic

C7) Sensitizer

C4) Irritant

Which chemical...

[D] Rapidly oxidizes, can result in combustion

D1) Corrosive

D2) Flammable

D3) Poison

D4) Irritant

D5) Oxidizer

D6) Toxic

D7) Sensitizer

D5) Oxidizer

Which chemical...

[E] May be fatal to human and animals?

E1) Corrosive

E2) Flammable

E3) Poison

E4) Irritant

E5) Oxidizer

E6) Toxic

E7) Sensitizer

E3) Poison

Which chemical...

[F] destroys living tissue on contact?

F1) Corrosive

F2) Flammable

F3) Poison

F4) Irritant

F5) Oxidizer

F6) Toxic

F7) Sensitizer

F7) Sensitizer

Which chemical...

[G] Causes adverse health effects

G1) Corrosive

G2) Flammable

G3) Poison

G4) Irritant

G5) Oxidizer

G6) Toxic

G7) Sensitizer

G6) Toxic

Which chemical is more dangerous: sodium hypochlorite (bleach) or ethylene glycol (antifreeze)

Signal Words:

Bleach - Danger

Antifreeze - Warning

Hazard Category:

Bleach - serious eye damage (Category 1), skin corrosion (Category 1B)

Antifreeze - acute toxicity, oral (Category 4), specific organ toxicity (Category 2)

Sodium hypochlorite based on the signal words and hazard categories provided

What should be done when handling a corrosive?

a) Carry bottles in secondary containers

b) If exposed wash off skin immediately

c) Know the location of eyewash stations and safety showers

d) Use concentrated solutions whenever possible

e) Use in fume hood if the corrosive is an inhalant hazard

f) Wear goggles, lab coat, and gloves

g) Wear long sleeved shirts, long pants, and liquid shedding close toed shoes

a) Carry bottles in secondary containers

b) If exposed wash off skin immediately

c) Know the location of eyewash stations and safety showers

e) Use in fume hood if the corrosive is an inhalant hazard

f) Wear goggles, lab coat, and gloves

g) Wear long sleeved shirts, long pants, and liquid shedding close toed shoes

What should be done in the event of a spill?

a) Contaminated clothing must be removed and treated as hazardous waste

b) Eyewashes should be used for at least 15 minutes

c) If solid is spilled on skin wash scrape off then wash with water

d) If splashed with a large quantity of liquid, wipe off contaminated clothing

e) Non-volatile liquid spills require lab evacuation

f) Spilled solid should be returned to its original bottle

g) Use a small brush and dustpan when cleaning up a solid

h) Use a spill pillow to absorb liquids with nontoxic vapors

a) Contaminated clothing must be removed and treated as hazardous waste

b) Eyewashes should be used for at least 15 minutes

c) If solid is spilled on skin wash scrape off then wash with water

g) Use a small brush and dustpan when cleaning up a solid

h) Use a spill pillow to absorb liquids with nontoxic vapors

Which of the following factors determines whether a solute will dissolve in a solvent?

a) molecular dipoles

b) molecular geometry

c) boiling point

d) intermolecular forces

e) electrostatic attraction

a) molecular dipoles

b) molecular geometry

d) intermolecular forces

e) electrostatic attraction

What are the strongest intermolecular forces that must be overcome when melting menthol?

a) Dipole-dipole interactions

b) Hydrogen bonding

c) Ion-dipole forces

d) van der Waals forces

b) Hydrogen bonding

Order the steps on using a digital balance

a) Determine the container to weigh chemicals into: small beaker, weighing paper, or weighing boat

b) Use a brush or paper towel to clean up spills in and around the balance

c) Close the draft shields and record the mass once the reading has stabilized

d) Use a spatula to transfer solid chemical into the container

e) Place the weighing container on the balance pan and press "Tare" or "Zero"

a) Determine the container to weigh chemicals into: small beaker, weighing paper, or weighing boat

e) Place the weighing container on the balance pan and press "Tare" or "Zero"

d) Use a spatula to transfer solid chemical into the container

c) Close the draft shields and record the mass once the reading has stabilized

b) Use a brush or paper towel to clean up spills in and around the balance

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[A] What is A (the bottom /)

A1) Gas

A2) Liquid

A3) Solid

A4) Liquid and Gas

A5) Solid and Liquid

A3) Solid

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[B] What is B (the first flat line ____)

B1) Gas

B2) Liquid

B3) Solid

B4) Liquid and Gas

B5) Solid and Liquid

B5) Liquid and solid

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[C] What is C (the middle /)

C1) Gas

C2) Liquid

C3) Solid

C4) Liquid and Gas

C5) Solid and Liquid

C2) Liquid

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[D] What is D (the top flat line ___)

D1) Gas

D2) Liquid

D3) Solid

D4) Liquid and Gas

D5) Solid and Liquid

D4) Liquid and Gas

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[E] What is E (the top /)

E1) Gas

E2) Liquid

E3) Solid

E4) Liquid and Gas

E5) Solid and Liquid

E1) Gas

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[F] What is F (the point when C turns into D)

F1) Sublimation point

F2) Boiling point

F3) Freezing point

F4) Condensation point

F5) Triple point

F6) Melting point

F2) Boiling point

Phase Change Diagram

................[F] __[D]__/ [E]

[G] __[B]__/ [C]

/ [A]

[G] What is G (the point when A turns into B)

G1) Sublimation point

G2) Boiling point

G3) Freezing point

G4) Condensation point

G5) Triple point

G6) Melting point

G6) Melting point

In the phase diagram for water, indicate the direction that the solid-liquid and the liquid-gas coexistence lines will move along the temperature axis after the addition of a solute.

Solid-liquid coexistence line:

a) Left

b) Right

c) Up

d) Down

a) Left

In the phase diagram for water, indicate the direction that the solid-liquid and the liquid-gas coexistence lines will move along the temperature axis after the addition of a solute.

Liquid-gas coexistence line:

a) Left

b) Right

c) Up

d) Down

b) Right

What effect do impurities (or solutes) have on the melting point of a substance?

a) lower the melting point

b) raise the melting point

c) have no effect on the melting point

a) lower the melting point

This colligative property (of solutes impacting the melting point of a substance) is called:

a) vapor pressure lowering

b) boiling point elevation

c) freezing point depression

d) osmotic pressure

c) freezing point depression

A solution is created when a small amount of [A] dissolves in a large amount of [B]

A1) normality

A2) kilogram

A3) solute

A4) molality

A5) solvent

A6) gram

A7) molarity

A3) solute

A solution is created when a small amount of [A] dissolves in a large amount of [B].

B1) normality

B2) kilogram

B3) solute

B4) molality

B5) solvent

B6) gram

B7) molarity

B5) solvent

When a solution's concentration is reported in moles of [C] per liter of solution, the concentration is reported as a [D].

C1) normality

C2) kilogram

C3) solute

C4) molality

C5) solvent

C6) gram

C7) molarity

C3) solute

When a solution's concentration is reported in moles of [C] per liter of solution, the concentration is reported as a [D].

D1) normality

D2) kilogram

D3) solute

D4) molality

D5) solvent

D6) gram

D7) molarity

D7) molarity

When a solution's concentration is reported in moles of [E] per [F] of solvent, the concentration is reported as a [G].

E1) normality

E2) kilogram

E3) solute

E4) molality

E5) solvent

E6) gram

E7) molarity

E3) solute

When a solution's concentration is reported in moles of [E] per [F] of solvent, the concentration is reported as a [G].

F1) normality

F2) kilogram

F3) solute

F4) molality

F5) solvent

F6) gram

F7) molarity

F2) kilogram

When a solution's concentration is reported in moles of [E] per [F] of solvent, the concentration is reported as a [G].

G1) normality

G2) kilogram

G3) solute

G4) molality

G5) solvent

G6) gram

G7) molarity

G4) molality

Which is true about responding to emergencies?

a) If possible turn off lab equipment before leaving lab for a fire alarm

b) Stay calm

c) Know where the stairwells are

d) All laboratories must have two exits

They're all true

a) If possible turn off lab equipment before leaving lab for a fire alarm

b) Stay calm

c) Know where the stairwells are

d) All laboratories must have two exits

Which are true?

a) Cinnamic acid dissolves in melted menthol

b) Cinnamic acid does not stay dissolved in solid menthol

c) Cinnamic acid solidifies when menthol freezes

d) Menthol dissolves when heated

e) None are true

a) Cinnamic acid dissolves in melted menthol

b) Cinnamic acid does not stay dissolved in solid menthol

How does weak acidity affect the freezing point depression?

a) The solution freezing point is higher than it should be.

b) The solution freezing point is lower than it should be.

c) The solvent freezing point is higher than it should be.

d) The solvent freezing point is lower than it should be.

b) The solution freezing point is lower than it should be.

What is the source of the above effect?

a) More particles are in solution because of dissociation

b) Neutralization releases heat.

c) The intermolecular forces between the solvent and solute are less than expected.

d) The solute is able to react with the solvent.

a) More particles are in solution because of dissociation

How will the calculated molecular mass differ from the actual value?

a) The calculated molecular mass cannot be determined.

b) The calculated molecular mass is higher.

c) The calculated molecular mass is lower.

c) The calculated molecular mass is lower.

Open Odyssey, go to the Miscellaneous tab, find the Solutions section and click on M I2 Molarity vs Molality. Follow the instructions on the screen and click on all the available buttons.

[A] Why is molality used instead of molarity in this project?

A1) Temperature affects the measurement of moles.

A2) Molality is easier to measure and calculate.

A3) Mass changes with intermolecular forces

A4) Volume changes with temperature

A4) Volume changes with temperature

Open Odyssey, go to the Miscellaneous tab, find the Solutions section and click on M I2 Molarity vs Molality. Follow the instructions on the screen and click on all the available buttons.

[B] Under what conditions are the values of molarity and molality very different?

B1) low temperatures

B2) high concentrations

B3) ionic compound solutes

B4) all of the above

B2) high concentrations

Open Odyssey, go to the Miscellaneous tab, find the Solutions section and click on M I2 Molarity vs Molality. Follow the instructions on the screen and click on all the available buttons.

[C] Which value is higher?

C1) molality

C2) molarity

C3) neither, the values are the same

C1) molality

Which of the following common household products contain flammable chemicals?

a) gasoline

b) rubbing alcohol

c) bleach

d) nail polish remover

e) antifreeze

f) liquid hand soap

a) gasoline

b) rubbing alcohol

d) nail polish remover

e) antifreeze

Which of the following are ways to stop a fire?

a) remove ignition sources

b) place a beaker over a small flame to remove oxygen

c) ground metal container to prevent static electricity

d) limit quantities of flammable substances in work area

All of the above

a) remove ignition sources

b) place a beaker over a small flame to remove oxygen

c) ground metal container to prevent static electricity

d) limit quantities of flammable substances in work area

Select the true statements:

a) Inflammable is another word for flammable

b) Flammable chemicals can be liquids or solids, gases don't burn

c) The boiling point of a flammable liquid is usually high

d) A fire cannot start above or below a vapor's flammability limits

e) Combustible is the same as flammable

f) All volatile chemicals are flammable

a) Inflammable is another word for flammable

d) A fire cannot start above or below a vapor's flammability limits

The National Fire Protection Association (NFPA) diamond has a [A] section for flammability.

A1) Red

A2) White

A3) Yellow

A4) Blue

A1) Red

If the number [B] appears in this section, the chemical is extremely flammable.

B1) 0

B2) 1

B3) 2

B4) 3

B5) 4

B5) 4

If the number [C] appears in this section, the chemical is a combustible, it will catch fire when heated.

C1) 0

C2) 1

C3) 2

C4) 3

C5) 4

C3) 2

The Global Harmonized System (GHS) symbol is a picture of a [D].

D1) fire

D2) fire with an O in the middle

D3) an explosion

D4) an exclamation point

D5) a skull and crossbones

D1) fire

If the hazard category is [E], the chemical is extremely flammable.

E1) HC1

E2) HC2

E3) HC3

E4) HC4

E1) HC1

If the hazard category is [F], the chemical is combustible.

F1) HC1

F2) HC2

F3) HC3

F4) HC4

F4) HC4

Order the steps for preparing and developing a TLC plate:

a) With a pencil draw a baseline

b) Use a capillary to deliver 1-2 drops of concentrated analyte solution

c) Allow the analyte spots to dry

d) Place plate in TLC chamber so that it doesn't touch filter paper

e) Cap TLC chamber

f) Remove plate before solvent front reaches the top of the plate

g) Mark the solvent front

h) Measure distances to calculate Rf values

a) With a pencil draw a baseline

b) Use a capillary to deliver 1-2 drops of concentrated analyte solution

c) Allow the analyte spots to dry

d) Place plate in TLC chamber so that it doesn't touch filter paper

e) Cap TLC chamber

f) Remove plate before solvent front reaches the top of the plate

g) Mark the solvent front

h) Measure distances to calculate Rf values

All the analyte spots are in the upper region of the TLC plate & close together

a) The developing chamber is not capped resulting in evaporation

b) The TLC plate was not allowed to dry between drops

c) The eluent used was too polar

d) The TLC plate was touching the filter paper wick

c) The eluent used was too polar

Analyte spots moved up the plate diagonally instead of vertically

a) The developing chamber is not capped resulting in evaporation

b) The TLC plate was not allowed to dry between drops

c) The eluent used was too polar

d) The TLC plate was touching the filter paper wick

d) The TLC plate was touching the filter paper wick

While spotting the analyte spot became too large

a) The developing chamber is not capped resulting in evaporation

b) The TLC plate was not allowed to dry between drops

c) The eluent used was too polar

d) The TLC plate was touching the filter paper wick

b) The TLC plate was not allowed to dry between drops

Rf values differ for 2 identically spotted plates from the same developing chamber containing 2:1 acetone:heptane eluent

a) The developing chamber is not capped resulting in evaporation

b) The TLC plate was not allowed to dry between drops

c) The eluent used was too polar

d) The TLC plate was touching the filter paper wick

a) The developing chamber is not capped resulting in evaporation

Which are true statements:

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

b) Exhaust air from fume hoods is recycled back through the lab

c) A tissue paper held at the bottom of a sash should blow into the hood

d) All work should be done at least 6 inches inside the hood

e) A fume hood has it's own power, it's okay to continue to work if the power fails

f) Room air should be drawn into the fume hood

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

c) A tissue paper held at the bottom of a sash should blow into the hood

d) All work should be done at least 6 inches inside the hood

f) Room air should be drawn into the fume hood

What is PEL?

a) immediately dangerous to life and health

b) gas concentration that 50% of the population can detect

c) occupational exposure limits

d) decreased sensitivity to odor over time

e) permissible exposure limit

e) permissible exposure limit

Odor Threshold

a) immediately dangerous to life and health

b) gas concentration that 50% of the population can detect

c) occupational exposure limits

d) decreased sensitivity to odor over time

e) permissible exposure limit

b) gas concentration that 50% of the population can detect

Odor Fatigue

a) immediately dangerous to life and health

b) gas concentration that 50% of the population can detect

c) occupational exposure limits

d) decreased sensitivity to odor over time

e) permissible exposure limit

d) decreased sensitivity to odor over time

IDLH

a) immediately dangerous to life and health

b) gas concentration that 50% of the population can detect

c) occupational exposure limits

d) decreased sensitivity to odor over time

e) permissible exposure limit

a) immediately dangerous to life and health

What is OEL?

a) immediately dangerous to life and health

b) gas concentration that 50% of the population can detect

c) occupational exposure limits

d) decreased sensitivity to odor over time

e) permissible exposure limit

c) occupational exposure limits

Which Chemical will you smell after it becomes hazardous?

a) hexane: 50ppm (PEL), 130ppm (Odor threshold)

b) dicholoromethane: 25 ppm (PEL), 130 ppm (Odor Threshold)

c) ethyl acetate: 400 ppm (PEL), 50 ppm (Odor Threshold)

d) methanol: 200 ppm (PEL), 5900 ppm (Odor Threshold)

When PEL is smaller than Odor Threshold:

a) hexane: 50ppm (PEL), 130ppm (Odor threshold)

b) dicholoromethane: 25 ppm (PEL), 130 ppm (Odor Threshold)

d) methanol: 200 ppm (PEL), 5900 ppm (Odor Threshold)

What is the major underlying principle of chromatography?

a) If the concentration of the component is too high, the spot will become a spear

b) The stationary phase will always be more polar than the mobile phase

c) Separation will be achieved is one component adheres to the stationary phase more than the other component does

d) High compound concentration facilitates visualizations

e) The solvent moves by capillary action

c) Separation will be achieved is one component adheres to the stationary phase more than the other component does

A student dissolved a product in acetone and spotted on a silica TLC plate to determine the purity of the product. A 2:1 mixture of heptane:acetone was placed in the developing chamber.

[A] Silica is...

A1) Analyte

A2) Mobile phase

A3) Stationary phase

A3) Stationary phase

A student dissolved a product in acetone and spotted on a silica TLC plate to determine the purity of the product. A 2:1 mixture of heptane:acetone was placed in the developing chamber.

[B] The heptane/acetone mixture is...

B1) Analyte

B2) Mobile phase

B3) Stationary phase

B4) Solid

B5) Eluent

B2) Mobile phase

B5) Eluent

Given a TLC Plate

- - - (Solvent Front)

- X -

X - -

- - X (Origin)

A B C

[A] Order in terms of Polarity (Least polar to Most Polar)

a) A

b) B

c) C

b) B

a) A

c) C

Given a TLC Plate

- - - (Solvent Front)

- X -

X - -

- - X (Origin)

A B C

[B] Why didn't C move from the baseline?

B1) C is strongly absorbed to the silica because of its polarity

B2) C is not soluble in the eluent

B3) C was not dissolved when spotted on the plate

B4) C in nonpolar, like the silica

B1) C is strongly absorbed to the silica because of its polarity

Given a TLC Plate

- - - (Solvent Front)

- X -

X - -

- - X (Origin)

A B C

Extract

- (Solvent Front)

X

X

- (Origin)

[C] What compounds are in the Extract?

a) A

b) B

c) C

a) A

b) B

What is true about the permanganate dip?

a) Permanganate enables the plate to fluoresce under UV light

b) Most of the plate turns pink because unreacted permanganate is pink

c) If a compound has double bonds its TLC spot turns yellow

d) Permanganate reduces double bonds

e) None of these

b) Most of the plate turns pink because unreacted permanganate is pink

c) If a compound has double bonds its TLC spot turns yellow

What statement about gloves is true?

a) Most gloves protect against most chemicals

b) Only non-disposable gloves protect against most chemicals

c) No glove material protects against all chemicals

d) Latex gloves are the best choice for most people working in lab

e) Gloves should be removed when they come in contact with any hazardous chemical

c) No glove material protects against all chemicals

e) Gloves should be removed when they come in contact with any hazardous chemical

What is true about gloves?

[A] Permeation

A1) Time for the first appearance of a chemical on the other side of the glove

A2) Speed at which a chemical appears on the other side of the glove

A3) Ability of a chemical to penetrate the glove material through small pores

A4) Destructive change in the glove material

A3) Ability of a chemical to penetrate the glove material through small pores

What is true about gloves?

[B] Degradation

B1) Time for the first appearance of a chemical on the other side of the glove

B2) Speed at which a chemical appears on the other side of the glove

B3) Ability of a chemical to penetrate the glove material through small pores

B4) Destructive change in the glove material

B4) Destructive change in the glove material

What is true about gloves?

[C] Breakthrough time

C1) Time for the first appearance of a chemical on the other side of the glove

C2) Speed at which a chemical appears on the other side of the glove

C3) Ability of a chemical to penetrate the glove material through small pores

C4) Destructive change in the glove material

C1) Time for the first appearance of a chemical on the other side of the glove

What is true about gloves?

[D] Time of transfer

D1) Time for the first appearance of a chemical on the other side of the glove

D2) Speed at which a chemical appears on the other side of the glove

D3) Ability of a chemical to penetrate the glove material through small pores

D4) Destructive change in the glove material

D2) Speed at which a chemical appears on the other side of the glove