Chem lab final
In case of accidental contact with chemicals, how long should the eyes be flushed at the eyewash station 5 mins Until the irritation is gone 30 minutes 15 minutes
15 minutes
Suppose you are performing a titration. At the beginning of the titration, you read the titrant volume as 1.02 mL. After running the titration and reaching the endpoint, you read the titrant volume as 25.39 mL. What volume, in mL, of titrant was required for the titration.
24.37
Fill in the palindromic sequence of the given DNA strand containing six bases 5' G A C G T C
3' C T G C A G
Calculate the Rf value for a spot in a TLC experiment if the solvent moved 12.7 cm and the spot moved 7.5 cm from the origin
0.59
For your data graph in the Proteases experiment, identify which variables will be plotted on each axis. Y axis- x axis-
Absorbance, time(sec)
What functional groups are present in all amino acids? Select one or more Alcohol Amine Amide Carboxylic acid
Amide and Carboxylic acid
Identify the types of information that are necessary to communicate with emergency responders. Select one or more The history of safety incidents in the lab Any other hazards present in the lab Any chemicals involved in an incident How the incident happened
Any other hazards present in the lab Any chemicals involved in an incident
When performing a melting point determination, how should you report your findings? As the temperature when the last bit of solid melts into liquid As the temperature when you first notice the appearance of liquid in the sample As the average between the temperatures when melting starts and when it ends As a range from the temperature when melting starts to the temperature when it ends
As a range from the temperature when melting starts to the temperature when it ends
A student removes a chemical sample from a reagent bottle to be used in an experiment. What should he do with any excess chemical remaining from this sample after the experiment is complete? Conduct a second trial of the experiment with the excess chemical. Clean a spatula thoroughly, then use it to add the chemical back into the reagent bottle. Discard the chemical down the sink under running water. Check and see if anyone else can use the chemical. If not, discard in the proper waste container.
Check and see if anyone else can use the chemical. If not, discard in the proper waste container.
What are the best practices for safely handling waste in the lab? Check labels or instructions before any disposal Always wear appropriate personal protective equipment Place any power towels from the clean-up in the trash Remove gloves for better manipulation of the waste containers
Check labels or instructions before any disposal Always wear appropriate personal protective equipment
What should you do after finishing work with a reagent bottle? Select one or more Leave the bottle open in case someone else needs it Close the bottle Return the bottle to its proper storage location Place the bottle in the Solid Waste container
Close the bottle Return the bottle to its proper storage location
In a TLC experiment, how do you identify the components of an unknown mixture? Combine the mixture with multiple known compounds and look for the largest spots. Compare the color of the mixture spots to the colors of pure known compounds. Combine the mixture with a series of known compounds and observe the color of the dots. Compare the Rf values of the mixture components to the Rf values of pure known compounds.
Compare the Rf values of the mixture components to the Rf values of pure known compounds.
What metal is responsible for the color change in a Benedict's test? Silver Copper Iodine Sodium
Copper
Which of the following names identifies an enzyme? Glycolysis Dehydrogenase Phosphoglucose Substrate
Dehydrogenase
In general, alcohols ______ when mixed with water because the _____ in alcohols can _______ water
Dissolve, O-H bonds, hydrogen bond with
Read each statement regarding food and beverages in the lab and determine if each is true or false Chewing gum is okay in the lab as long as you don't blow bubbles Beverages are allowed in lab as long as they are in containers with lids Tobacco products of all kinds are prohibited in lab Food items should not be brought into the lab.
False, False, True, True
If you drop or break glassware in lab, first Then, Finally, place all that material into the
Get thick gloves or dustpan, carefully collect all the broken glassware, broken glass container
Determine the safest option in the lab if you need your vision to be corrected. Wear your corrective glasses or lenses as normal for the whole experiment Wear safety goggles while working and switch to corrective glasses when you need to read something Wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your TA or Instructor for your school's policy Wear safety goggles without any corrective lenses for the whole experiment
Wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your TA or Instructor for your school's policy
Determine when you should remove your goggles in the lab room. When you have finished cleaning up your chemicals and glassware Whenever your goggles become foggy or uncomfortable Whenever you need to lean in close to get a volume reading When everyone in the room is done handling any chemicals or glassware
When everyone in the room is done handling any chemicals or glassware
When heating liquids in a test tube, it is important that the test tube be positioned ________, pointed ______ people, and
at an angle, away from, half-full
A flexible polymer used in the manufacturing of grocery bags. The molecular structure is (C2H4)n
High density polyethylene
What elements make up a carbohydrate? Hydrogen Oxygen Nitrogen Carbon
Hydrogen, nitrogen, and carbon
Which substance is not a carbohydrate? Lipid Sugar Starch FIber
Lipid
Identify the precautions to take with exits in the lab Select one or more Keep the exit door locked at all times Make sure lab windows are always open Locate the exits prior to the start of lab Do not block a door with an EXIT sign
Locate the exits prior to the start of lab, do not block a door with an exit sign
What type of inhibition is occurring when the inhibitor may bind to either the enzyme or the enzyme-substrate complex? Competitive Uncompetitive Irreversible Noncompetitive
Noncompetitive
A polymer produced through a condensation reaction, with applications ranging from clothing to packaging.
Polyethylene terephthalate
What is generally the best approach when liquid from a large reagent bottle is needed in an experiment? Pour liquids directly from a reagent bottle only when a funnel is placed securely underneath. Dispense the liquid directly from the reagent bottle whenever it is needed. Insert a pipet into the reagent bottle as many times as needed to get the desired amount of liquid. Pour some of the reagent from the bottle into a beaker, then use as needed in the procedure.
Pour some of the reagent from the bottle into a beaker, then use as needed in the procedure.
It is often helpful to remember the acronym PASS when using a fire extinguisher. Fill in the word that corresponds with each letter to complete the steps needed for operation of this device. P___ the pin A__ the nozzle at the base of the fire S______ the lever slowly S____ the spray from side to side over the fire
Pull, Aim, Squeeze, sweep
What is the first step for response to an emergency situation? Yell for help and assist with the evacuation of the lab. Discuss the situation with the other students until everyone agrees on what to do. Remain calm and quiet, gather information, and assess the situation. Run outside the building as quickly as possible and call 911
Remain calm and quiet, gather information, and assess the situation.
Determine the best way to deal with each of the following items Long necklaces- Loose bracelets- Long hair- Flowy sleeves- Long earrings
Remove Remove Tie back or secure Tie back or secure Remove
What property is used to separate DNA fragments during a gel electrophoresis experiment? Identity of bases Polarity Electronegativity Size
Size
Which statements accurately describe soap? Select one or more Soaps are both hydrophobic and hydrophilic Soaps work in solutions of any pH Soaps should be weakly alkaline in solution Soaps are a mixture of fatty acids salts and glycerol
Soaps are both hydrophobic and hydrophilic, soaps should be weakly alkaline in solution, Soaps react with ions in hard water to create a precipitate
Identify the type of sugar corresponding to each name Starch Fructose Glucose Monosaccharide Lactose Sucrose
Starch-polysaccharide Fructose-Monosaccharide Glucose-Monosaccharide Lactose-Disaccharide Sucrose- Disaccharide
Why do you need to support a vacuum filtration? The side-arm flask cannot sit directly on the benchtop. The filter funnel is held in place by the clamp. The filter funnel makes the apparatus top- heavy The side-arm flask does not work without a clamp.
The filter funnel makes the apparatus top-heavy.
The synthesis of nylon requires solutions of 5% hexamethylenediamine and 5% adipoyl chloride. This polymer will form __________________________ To remove the nylon, ___________________
in between layers of the solutions, catch on the tip of a sharp object
When testing the solubility of compounds containing -OH groups, check the solubility _____ first If the compound is soluble under that condition, its solubility ________ does not need to be tested
in water, in aqueous NaOh
The titration of Vitamin C with iodine proceeds according to the given equation C6H8O6 + I2 -> C6H6O6 + 2HI Suppose it takes 17.17 mL of 0.0026 M I2 solution to reach the end point of the titration. How many moles of vitamin c are present
0.000045
The titration of Vitamin C with iodine proceeds according to the given equation C6H8O6 + I2 -> C6H6O6 + 2HI Suppose it takes 14.54 mL of 0.0053 M I2 solution to reach the endpoint of the titration. How many moles of I2 reacted?
0.000077
In a reaction, there are multiple ways to discuss the amount of compound produced. Identify the definition of each term related to the reaction yield. 1. The amount of product experimentally produced 2. The calculated amount of product under ideal conditions 3. The comparison of the experimental amount of product to the calculated amount
1- actual yield 2- theoretical yield 3- percent yield
Match the definition to the type of polymer it describes. Options Condensation or Addition polymer A polymer formed as monomers link together without forming a byproduct. _______________ A polymer formed as monomers link together, forming a small molecule as a byproduct. _____________________
1. Addition polymer 2. Condensation polymer
Identify the chromatography term that corresponds to each definition. The substance to which the sample is bound at the start of an experiment- A method used to separate components of a mixture- A value that quantifies the distance traveled by a substance relative to the distance traveled by the solvent- The substance that carries the components of a mixture-
1. Stationary phase 2. Chromatography 3. Rf 4. Mobile phase
Fill in the words to complete the stops in the process of recrystallization. 1. Dissolve a substance in a _______ amount of hot solvent 2. Allowing the solvent to cool, percipitating the ______ while ______ remain in solution 3. _______ the mixture to collect the pure substance
1.minimal 2. substance, impurities 3. Filter
If crystal growth doesn't start on its own after the solution in the flask returns to room temp, identify the best ways to promote this process Select one or more: Add a bit of solid as a seed crystal Scratch the bottom of the flask gently with a stirring rod Place the flask on a hot plate to evaporate some solvent Add ice cubes to the solution
Add a bit of solid as a seed crystal, scratch the bottom of the flask gently with a stirring rod
Identify factors that impact the function of an enzyme Select one or more pH Temperature Concentration of substrate Concentration of enzyme Presence of inhibitor
All of the above
Which signs are typically posted in areas of active lab work? Select one or more Chemical storage signs Personal protective equipment (PPE) sign Sign prohibiting food and drink Safety equipment signs
All of the above
What is a protease? An enzyme that breaks down a protein into individual amino acids A protein consisting of a chain of amino acids A component of foods such as fruit juices All of the above are correct.
All of the above are correct
Which statement concerning the effectiveness of enzymes is NOT true? An enzyme may not function outside a certain pH range. Although the actions of different enzymes may vary, the effectiveness of each particular enzyme is constant. Enzymes are affected by salt concentration. The effectiveness of an enzyme is likely to vary over a range of temperatures.
Although the actions of different enzymes may vary, the effectiveness of each particular enzyme is constant.
Which functional group on the structure of p-aminophenol will react with acetic anhydride to produce acetaminophen? Select one: Carboxylic acid Ester Phenol Amine
Amine
What are the reasons to determine the melting point of a sample in a melting point apparatus? Select one or more Assessment of the sample's purity Removal of impurities from the sample Identification of an unknown sample Conversion of the solid sample to liquid
Assessment of the sample's purity and Identification of an unknown sample
Soaps clean up dirt by acting as ______. The nonpolar chain in the soap is attracted to the ____ and the ionic end is attracted to the _____. Thus, the soap creates ______ that wash the dirt away with the water.
Emulsifying agents, dirt, water, dispersed droplets
What info is needed in order to be prepared for an emergency? Select one or more: Location of all exits Understanding of where to go should an emergency occur Contact information for emergency personnel Full inventory of all chemicals presents in the lab Location of lab phone and first aid kit
Location of all exits, Understanding of where to go should an emergency occur, Contact information for emergency personnel, Location of lab phone and first aid kit
Identify effective techniques for accurate pipet use Select all that apply Use the pipet bulb to force the last drop out of the tip Leave any air bubbles in a pipet that occur after drawing up liquid Measure liquid by aligning the meniscus with the volume line Do not let liquid enter the pipet bulb or pump
Measure liquid by aligning the meniscus with the volume line Do not let liquid enter the pipet bulb or pump
If inhaled- In case of skin contact- In case of eye contact- If swallowed-
Move person to fresh air Take off any contaminated clothing and rinse thoroughly Rinse with water for 15 minutes Rinse mouth with water
Identify the three types of reversible inhibitors A molecule that limits the effectiveness of the enzyme without binding to the active site. _________ A molecule that binds to the enzyme-substrate complex. ___________ A molecule that binds to the enzyme active site instead of the substrate. __________
Noncompetitive, uncompetitive, competitive
Octyl formate is an ester that has the flavor of oranges. It can be synthesized from an alcohol and a carboxylic acid What alcohol is needed to make octyl formate? What carboxylic acid is needed to make octyl formate?
Octanol and formic acid
To run a thin layer chromatography experiment with a chemical substance, begin by marking a horizontal line near the bottom of a TLC plate with _________. Place a _____ spot of the substance onto the line. For the mobile phase, add a small amount of ______ at the bottom of a TLC chamber. Plate the plate, in then _____ the chamber. Once the mobile phase approaches the top of the plate, remove the plate and mark the ______ line. Note the position of the spots and calculate Rf values if needed.
Pencil, small, solvent, cover, solvent
Polypropylene is a polymer with a density of 0.89g/mL. Review the density table given and identify the expected observations if polypropylene is added to a beaker containing each liquid Water density 1.00 g/mL methanol 0.79 g/mL ethanol 0.79 g/mL hexane 0.66 g/mL Select one or more Polypropylene will float in water. Polypropylene will float in hexane Polypropylene will float in methanol Polypropylene will sink in ethanol
Polypropylene will float in water Polypropylene will sink in ethanol
A rigid, brittle polymer used in disposable food containers. The backbone of the polymer contains phenyl rings.
Polystyrene
A rigid polymer used often in construction materials. The structure contains a halogen.
Polyvinyl chloride
Amino acids can be either polar or non-polar based on their: In general, amino acids are non-polar if _________ are present. Such amino acids are also referred to as ______. Other amino acids are polar and are generally referred to as __________.
R-groups, only carbon and hydrogen, hydrophobic, hydrophillic.
What effect do restriction enzymes have on DNA? Restriction enzymes cleave DNA at specific sequences into fragments Restriction enzymes give a negative charge to DNA. Restriction enzymes repair damaged portions of DNA. Restriction enzymes duplicate DNA.
Restriction enzymes cleave DNA at specific sequences into fragments
How should spill cleaning materials be discarded? Leave them in the fume hood for the instructor. Seal in a labeled plastic bag, then place in the solid waste container. Discard all components in the broken glass container. Rinse the cleaning materials in the sink, then place them in the trash can.
Seal in a labeled plastic bag, then place in the solid waste container.
Determine where to dispose each type of waste Syringe tips Broken flask Unused solid reagent Titrant solution
Sharps container Box lined with puncture resistant bag Solid waste container Nalgene bottle with cap
What should you do every time before you leave the lab? Select one or more Wash your hands Remove your lab coat, if you are wearing one Turn off the lights Remove your gloves
Wash your hands, remove your lab coat, if wearing one, and remove your gloves
When should you start a new chemical waste container in the lab? When the contents of the current container completely fill the container to the brim When the contents of the current container are a couple inches below the brim of the container When you accidentally spill chemicals down the side of the current container When you need to dispose of another chemical that is compatible with chemicals in the current container
When the contents of the current container are a couple inches below the brim of the container
In general, alcohols ____ when mixed because the ___ in alcohols can ____ water
dissolve, O-H bonds, hydrogen bond with
Changing gloves often will minimize the spread of chemicals. To properly remove gloves, first, ___________________, and then, __________ . Then insert _______ between the interior edge of the second glove and the skin and remove the second glove.
grasp the exterior of one glove with a gloved hand, peel off the first glove, a bare finger
Fill in the term to finish the description of each type of structural change of a protein. When a protein is ______, the bonds between amino acids are cleaved and the protein is broken down into individual amino acids. When a protein is _______, the protein loses its shape.
hydrolyzed, denatured
The purpose of the best-fit line on an experimental scatterplot is to ______________________________________________. The best-fit line allows us to _________________________.
identify any linear trend in scattered data, predict behavior between measured data using its slope.
When testing the pH of a solution with pH or litmus paper, dip a ________ in the solution. Add a drop of the solution to the paper. Compare the ___ of the pH paper to the scale that appears on the container.
stirring rod, drop, color
Match each titration term with its definition Solution of an unknown concentration that has another solution slowly added to it- Process of slowly adding a solution to react with another solution and determine the concentration of one of the solutions based on the reaction between them- Glassware that allows a solution to be precisely and slowly added to another solution- A reagent added to the analyte solution that changes color when the reaction is complete- When the required amount of one solution has been added to the second solution to complete the reaction- Solution of known concentration that is slowly added to a solution of unknown concentration-
1. Analyte 2. Titration 3. Buret 4. Indicator 5. Endpoint 6. Titrant
Determine whether each phrase describes carboxylic acids or esters. Form hydrogen bonds amongst themselves and have lower vapor pressure- Don't form hydrogen bonds amongst themselves and have lower vapor pressure- Usually have a sour odor- Notable for their pleasant fragrances- Their reactions with base are known as neutralizations- Their reactions with base are known as saponifications-
1. Carboxylic acids 2. Esters 3. Carboxylic acids 4. Esters 5. Carboxylic acids 6.Esters 7. Carboxylic acids 8. Esters
Identify the term that applies to each definition A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer- A measurement of the amount of light that passes through a sample- A unit commonly used in spectrophotometry that is inversely proportional to energy and commonly measured in nanometers- A sample prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance- A measurement of the amount of light taken in by a sample-
1. Cuvette 2. Transmittance 3. Wavelength 4. Blank 5. Absorbance
Multiple qualitative tests can be used to determine the properties of carbohydrate samples. Identify the test that provides the given information about carbohydrates. Distinguish between ketoses and aldoses- Distinguish between a pentose and a hexose- Determine whether carbohydrates are present- Distinguish between monosaccharides and disaccharides- Identify reducing sugars-
1. Seliwanoff's test 2. Bial's test 3. Molisch test 4. Barfoed's test 5. Benedict's test
Some carbohydrates are classified as reducing sugars due to their ability to reduce other reagents What features or a carbohydrate usually indicate that is a reducing sugar? Select one or more Only acetals are present in the sugar The sugar is a disaccharide There is a hemiacetal in the ring form There is an aldehyde in the chain form
The sugar is a disaccharide There is a hemiacetal in the ring form There is an aldehyde in the chain form
Which is NOT a good source of information about the hazards that affect waste disposal in a chemistry lab? Select one: The SDS The chemical bottle labels Your lab partner Your instructor's directions
Your lab partner
An indicator is a substance added to a sample that has _________ change, such as ______ change, in response to the _______ of the sample
a visible, color, chemical composition
Most chemicals can be cleaned up with a general spill kit, but a few chemicals require specialized spill procedures. For each substance listed, determine whether a general spill kit is sufficient or if a specialized spill kit is needed Mercury Phosphoric acid Hydrofluoric acid Methanol Acetone
mercury- special phosphoric acid- general hydrofluoric acid- special methanol- general acetone- general
Fructose is an example of ketohexose. The -hexose part of the name indicates that fructose is a _________ that contains ________ carbons The keto- part of the name indicates that fructose contains a ____ functional group. Fructose can combine with glucose to form sucrose. Therefore, sucrose is a _______
monosaccharide, 6 ketone, disaccharide
To see amino acids on a developed chromatography paper or plate, you can react it with _______ after __________
ninhydrin, letting the paper dry
The titration of Vitamin C with iodine proceeds according to the given equation C6H8O6 + I2 -> C6H6O6 + 2HI In this reaction, vitamin C is ______ and iodine is _____
oxidized and reduced
Identify the section in which each type of information can be found on a Safety Data Sheet. recommended personal protective equipment (PPE) - recommendations in case of accidental contact with the chemical- incompatibility or reactivity with other chemicals- chemical name and formula- possible dangers and health effects-
recommended personal protective equipment (PPE)-Exposure Controls/Personal Protection recommendations in case of accidental contact with the chemical-First Aid Measures incompatibility or reactivity with other chemicals- Handling and Storage chemical name and formula- Identification possible dangers and health effects-Hazards Identification
Move the safety shower if you spill hazardous chemicals on your ____ or ______ . Stand under the shower and ___ the lever. remove clothing and continue flushing the area for ____ minutes
skin or clothing, pull, 15
After the reaction of base with the fat or oil to form a soap, add a saturated solution of ________. This addition helps ________ the soap as it increases the ______ of the solution so the soap floats on top
sodium chloride, precipitate, density
In order to dissolve a chemical sample in a recrystallization solvent, add the room temperature solvent _____________ in an Erlenmeyer flask on a hot plate. Turn on the heat, starting at __________. Using a ________, add additional solvent from a second container on the heat source. Swirl the sample flask after each addition, and try to add __________ in order to dissolve the solid.
1. just until it covers the sample 2. A low setting and increasing gradually 3. Pipet 4. as little solvent as possible
Which info doesn't need to be included a chemical waste label? Select one Names of the chemical compounds present in the container Relative amounts of chemical compounds in the container The date the waste container was filled completely A description of the experiment the chemicals were used for
A description of the experiment the chemicals were used for
A polymer is _________ made of ________, known as _______. Polymers can be natural, such as ______, or synthetic, such as _______
A polymer is a macromolecule made of many repeated subunits known as monomers. Polymers can be natural such as proteins or synthetic such as plastics.
Seliwanoff's test shows the presence of A positive seliwanoff's test appears as A negative seliwanoff's test appears as
Ketoses A red solution A light pink solution
Determine when to put on disposable gloves for work in the lab After setting up all the glassware but before handling chemicals Before handling any glassware or chemicals for the experiment Before entering the laboratory room After cleaning all the glassware for the experiment
Before handling any glassware or chemicals for the experiment
In order to use a pipet, place a _______ at the top of the pipet. Use this object to fill the pipet such that the _______ of the liquid is even with the volume line. Release the liquid, touching the top of the pipet to the side of the container if necessary to release the last drop _______ the pipet tip
Bulb or pump, meniscus, outside
Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once. When pulling an empty beaker of the shelf at the beginning of lab, it slips out of your hand on the floor. While picking up a buret, an unknown solution left by a previous solution drip onto your hand. While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench. While checking on a stirring solution, the solution splashes up towards your face.
Closed toe shoes, gloves, lab coat, goggles
After an electrophoresis experiment, how are the lengths of the DNA fragments in each lane determined? Comparing to a standard DNA ladder in one lane Finding the time it takes for each fragment to reach the end of the gel Measuring the length each fragment travels across the gel Calculating the rate based on factors such as voltage and time
Comparing to a standard DNA ladder in one lane
What information is necessary to review in order to be considered familiar with the Safety Data Sheet of a substance? Select one or more Literature examples of use of the substance Handling, storage, and reactivity information Personal protection and first aid recommendations Identification and description of substance Hazard warnings
Handling, storage, and reactivity information, Personal protection and first aid recommendations, Identification and description of substance, Hazard warnings
When using organic chemicals, there are additional precautions and recommendations to work safely in lab. Match each statement with the best corresponding lab practice or reason. Perform procedures in the fume hood if possible- Many organic chemicals involve _______________ Don't use open flames, like Bunsen burners- Many organic chemicals are __________ Use glass containers, unless instructed to do otherwise- Many organic chemicals dissolve ______ Rinse the glassware with organic solvents after the experiment- Many organic chemicals don't dissolve in _______
Harmful vapors, flammable, Plastics, and water
Which tests show can be used to show that a phenol is present? Select one or more: Iodine test Iron (III) chloride test Lucas test Acidity test
Iron chloride test, acidity test
Which steps are necessary for cleaning a spill involving broken glass? Stop the spread of the spill Soak up any spilled liquid with absorbent material Pick up large pieces of glass with gloved hands Wash off the broken glass for recycling
Stop the spread of the spill, soak up any spilled liquid with absorbent material. pick up large pieces of glass with gloved hands.
Identify the enzyme terms described in each statement A compound that has a reaction an enzyme speeds up- A protein that is no longer in the shape needed to function- A substance that limits or stops the activity of an enzyme- Specific arrangement maintained by intermolecular forces needed for an enzyme to work-
Substrate, Denatured, Inhibitor, Native structure
Which process would restore a fatty acid from a soap? Emulsification in water Esterification The addition of a base The addition of an acid
The addition of an acid
