lab flow 1-10
Determine whether or not each combination of substances can be used to create a buffer. 1 M Na2HPO4, 1 M NaH2PO4 : 0.1 M NH4Cl, 0.1 M HCl: 0.4 M KOH, 0.2 M NaOH: 0.1 M HCl, 0.1 M KCl: 0.05 M HNO2, 0.05 M NaNO2:
1 M Na2HPO4, 1 M NaH2PO4 : Buffer 0.1 M NH4Cl, 0.1 M HCl: Not a buffer 0.4 M KOH, 0.2 M NaOH: Not a buffer 0.1 M HCl, 0.1 M KCl: Not a buffer 0.05 M HNO2, 0.05 M NaNO2: Buffer
What is the correct reading of the volume in the pictured buret? Make sure to report your reading with the appropriate significant figures. Select one: 18.68 mL 17.32 mL 18.7 mL 17.325 mL 17.4 mL 17.3 mL
17.32 mL
Identify the description that applies to the substance represented by each NFPA diamond.
1. has a flash point below room temperature 2. stable, has health risks but no special hazards. 3. moderately unstable or reactive 4. oxidizer, not flammable
Identify which balance was used to make each mass reading. 1.230 g: 6.539 g: 4.0000 g: 0.90 g: 5.43 g:
1.230 g: A balance with ±0.001 g tolerance 6.539 g: A balance with ±0.001 g tolerance 4.0000 g: A balance with ±0.0001 g tolerance 0.90 g: A balance with ±0.01 g tolerance 5.43 g: A balance with ±0.01 g tolerance
Choose the best graduated cylinder to make each measurement in a single use. 18.5 mL of a NaClNaCl solution: 5.75 mL of a sucrose solution: 36 mL of water:
18.5 mL of a NaClNaCl solution: A 25 mL graduated cylinder with markings every 1 mL 5.75 mL of a sucrose solution: A 10 mL graduated cylinder with markings every 0.1 mL 36 mL of water: A 50 mL graduated cylinder with markings every 10 mL
The addition of chromic acid or chromate is a qualitative test for alcohols as the reaction causes a color change. However, not all alcohols react with chromic acid or chromate. Determine whether the named alcohol will react with chromic acid or chromate to cause a color change. 3-ethyl-3-pentanol: 2-pentanol: 3-hexanol: 1-butanol:
3-ethyl-3-pentanol: no color change 2-pentanol: color change 3-hexanol: color change 1-butanol: color change
What is the correct reading for the graduated cylinder in the close-up? Make sure to report your reading with the appropriate significant figures. Select one: 41 mL 40.05 mL 40.50 mL 39.5 mL 40.5 mL
40.5 mL
Which of the following represents an alpha particle? A: 42He24He B: −10e−10� C: 00γ00�
A
Identify the correct descriptions of beta particles. Select one or more: A beta particle is a high-energy electron. A beta particle has a negative charge. A beta particle is less massive than a gamma ray. A beta particle contains neutrons.
A beta particle is a high-energy electron. A beta particle has a negative charge.
When should you return a hot plate to the shelf? Select one: Immediately after the experiment is done After testing that the clean hot plate feels cool After wiping down the hot surface of the hot plate After the hot plate appears to be cool
After testing that the clean hot plate feels cool
Identify the expected result of the iodine test with different carbohydrates. Amylose: Cellulose: Glycogen: Sucrose
Amylose: Blue-black solution Cellulose: Red-brown solution Glycogen: Red-purple solution Sucrose: no reaction
Identify the correct descriptions of alpha particles. Select one or more: An alpha particle is a helium nucleus. Alpha particles are more massive than beta particles. An alpha particle is a form of electromagnetic radiation. An alpha particle has a negative charge.
An alpha particle is a helium nucleus. Alpha particles are more massive than beta particles.
Identify the necessary parts to build a calorimeter. Select one or more: An exterior paper cup An exterior styrofoam cup Thermometer Conductivity probe An interior paper cup Cover Cover An interior styrofoam cup
An exterior styrofoam cup Thermometer Cover An interior styrofoam cup
Identify the medical applications of aspirin. Select one or more: Anti-inflammatory agent Fever reducer Anti-histamine Pain killer check_circle_outline Blood thinner
Anti-inflammatory agent Fever reducer Pain killer
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 chemicals involved in an incident. Any other hazards present in the lab. How the incident happened.
Any chemicals involved in an incident. Any other hazards present in the lab. How the incident happened.
What is the best safety approach when working with unknown chemical substances? Select one: Assume that the substance is hazardous. Always wear appropriate PPE and take steps to prevent contact. Do not begin working with a substance unless you know exactly what it is. Assume that any substance distributed to lab participants is non-toxic and not a safety risk. Read the procedure and try to guess what the unknown substance is, then review its specific safety information.
Assume that the substance is hazardous. Always wear appropriate PPE and take steps to prevent contact.
Suppose you are going to perform a TLC experiment, which materials will you use to prepare the TLC development chamber? Select one or more: Beaker Watch glass Filter paper Erlenmeyer flask Stir bar Funnel
Beaker Watch glass Filter paper
Determine when to put on disposable gloves for work in the lab. Select one: After setting up all the glassware but before handling chemicals. After cleaning all the glassware for the experiment. Before entering the laboratory room. Before handling any glassware or chemicals for the experiment.
Before handling any glassware or chemicals for the experiment.
When should lab participants look at the Safety Data Sheet (SDS) of a substance? Select one: Before using the substance Only if the substance is perceived to be dangerous After completing work with the substance While working with the substance in lab
Before using the substance
Aspirin was formed to reduce the irritation of salicylic acid. However, aspirin can still disturb the stomach. Which functional group in aspirin is responsible for stomach irritation?: Select one: Ketone Ester Phenol Carboxylic acid
Carboxylic Acid
What functional groups are present in all amino acids? Select one or more: Carboxylic acid Amine Alcohol Amide
Carboxylic acid Amine
Identify the precautions to take with exits in the lab. Select one or more: Make sure lab windows are always open. Do not block a door with an EXIT sign. Locate the exits prior to the start of lab. Keep the exit door locked at all times.
Do not block a door with an EXIT sign. Locate the exits prior to the start of lab.
In a chromatography experiment, how do you identify the components of an unknown mixture? Select one: Compare the color of the mixture spots to the colors of pure known compounds. Combine the mixture with multiple known compounds and look for the largest spots. Compare the Rf values of the mixture components to the Rf values 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.
The equation to calculate density is, ______, , where D is the density, m is the _________, and V is the ___________
D=m/v, mass, volume
Consider the trendline on a graph of Mass vs. Volume of a solid or a liquid. What information can be obtained about the substance from the slope of this line? Select one: Density Specific heat Diameter Surface area
Density
Determine whether the stopcock should be completely open, partially open, or completely closed for each activity involved with titration. Filling the buret with titrant________ Close to the calculated endpoint of a titration _________ Conditioning the buret with titrant________ At the beginning of a titration_______
Filling the buret with titrant completely closed Close to the calculated endpoint of a titration partially open Conditioning the buret with titrant completely closed At the beginning of a titration completely open
When reacting yeast with sugars, what is the most prominent evidence that fermentation has occurred? Select one: A temperature decrease Formation of a solid A color change Formation of a gas
Formation of Gas
Identify the type of sugar corresponding to each name: Fructose: Glucose: Starch: Lactose: Sucrose:
Fructose: Monosaccharide Glucose: Monosaccharide Starch: Polysaccharide Lactose: Disaccharide Sucrose: Disaccharide
Identify the acid associated with each conjugate base. I- OH- NH3 CI- F-
I- : HI OH- : Water NH3: Ammonium IOn CI-: HCI F-: HF
For each described liquid, determine the behavior of a hydrometer calibrated around the density of pure water. In a liquid that is more dense than water: In a liquid that is less dense than water: In a liquid with the same density as water:
In a liquid that is more dense than water: float higher than position in pure water In a liquid that is less dense than water: Float lower than position in pure water In a liquid with the same density as water: Float in the same position as pure water
Read the Safety Data Sheet (click SDS icon below) of hydrogen peroxide to identify the recommended way to store this substance. Select one: In an open container in a bright and humid environment In a tightly closed container in a dry and well-ventilated place In a glass, leak-proof bottle on a shelf or cabinet In a well-ventilated container in a closed, dry area
In a tightly closed container in a dry and well-ventilated place
Review the Safety Data Sheet (SDS) (click the SDS icon below) for hydrogen peroxide, then identify the best course of action for each type of chemical exposure. In case of eye contact__________ If inhaled____ If swallowed____ In case of skin contact_____
In case of eye contact: rinse with water for 15 mins If inhaled: move person to fresh air If swallowed: rinse mouth with water In case of skin contact: take off any contaminated clothing and rise thoroughly
Which tests show can be used to show that a phenol is present? Select one or more: Iron(III) chloride test Acidity test Lucas test Iodine test
Iron(III) chloride test Acidity test
Most laboratory chemical spills are cleaned up in a similar manner, but acid and base spills require an extra step. What is this extra step? Select one: Tell all other lab participants to evacuate the lab as quickly as possible. Alert the proper authorities about the corrosive chemical waste. Be sure to replace the spilled acid or base. Neutralize the spill before cleaning it up.
Neutralize the spill before cleaning it up.
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: Choose..Pull the pin. A: Choose...the nozzle at the base of the fire. S: Choose...the lever slowly. S: Choose... the spray from side to side over the fire.
P: Pull the pin. A: Aim the nozzle at the base of the fire S: Squeeze the lever slowly S: Sweep the spray from side to side over the fire.
Aspartame is the methyl ester of a dipeptide made of phenylalanine and aspartic acid. What are the expected products of the hydrolysis of aspartame? Select one or more: Formamide Phenylalanine Diketopiperazine Aspartic acid Alanine Methanol
Phenylalanine Aspartic acid Methanol
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 hydrophilic
Identify whether each substance is an acid or base. RbOH HNO2 Ba(OH)2 KOH HClO4
RbOH: base HNO2: acid Ba(OH)2: base KOH: base HClO4: acid
What is the first step for response to an emergency situation? Select one: Run outside the building as quickly as possible and call 911. Discuss the situation with the other students until everyone agrees on what to do. Yell for help and assist with the evacuation of the lab. Remain calm and quiet, gather information, and assess the situation.
Remain calm and quiet, gather information, and assess the situation.
What should you do every time before you leave the lab? Select one or more: Remove your labcoat, if you are wearing one. Remove your gloves. Turn off the lights.Remove your labcoat, if you are wearing one. Remove your gloves. Turn off the lights. Wash your hands. Wash your hands.
Remove your labcoat, if you are wearing one. Remove your gloves. Wash your hands.
Two compounds might have spots with the same Rf value in a chromatography experiment and not be identical compounds. Which proposed chromatography experiment could best help determine whether the compounds are identical? Select one: Repeat the original experiment with a different solvent system Repeat the original experiment with a mixture of the compounds in a single spot Repeat the original experiment with the development chamber jar open Repeat the original experiment with larger spots of each compound
Repeat the original experiment with a different solvent system
Identify the chromatography term that corresponds to each definition. A value that quantifies the distance traveled by a substance relative to the distance traveled by the solvent: The substance to which the sample is bound at the start of an experiment: The substance that carries the components of a mixture: A method used to separate components of a mixture:
Rf stationary phase mobile phase chromatography
How should spill cleaning materials be discarded? Select one: Seal in a labeled plastic bag, then place in the solid waste container. Leave them in the fume hood for the instructor. 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.
Select one or more: Soaps are both hydrophobic and hydrophilic. Soaps work in solutions of any pH. Soaps react with ions in hard water to create a precipitate. Soaps should be weakly alkaline in solution. Soaps are a mixture of fatty acid salts and glycerol.
Soaps are both hydrophobic and hydrophilic. Soaps react with ions in hard water to create a precipitate. Soaps should be weakly alkaline in solution.
Fill in the words to complete each step in liquid spill cleanup. Surround the area with ________________, then cover the spill. Scoop up the material and place in a __________. Place the bagged waste in a ____________. Wipe down the area with ______________.
Surround the area with absorbent material then cover the spill. Scoop up the material and place in a plastic bag. Place the bagged waste in a solid waste container. Wipe down the area with detergent and water.
Under what conditions should a student inform the instructor of a lab injury? Select one: The instructor needs to be alerted only if he or she needs to call 911. The instructor should be alerted only if the injury involves broken skin. The instructor should be alerted only if the lab injury appears different from injuries the student has experienced previously. The instructor must be informed of all laboratory injuries.
The instructor must be informed of all laboratory injuries.
Some carbohydrates are classified as reducing sugars due to their ability to reduce other reagents. What features of a carbohydrate usually indicate that it is a reducing sugar? Select one or more: The sugar is a disaccharide. Only acetals are present in the sugar. There is an aldehyde in the chain form. There is a hemiacetal in the ring form.
There is an aldehyde in the chain form. There is a hemiacetal in the ring form.
Before running a titration, you calculate the expected endpoint. However, when performing the experiment, you pass the expected endpoint with no visible color change. What is the most likely problem with the titration set-up? Select one: There is not enough indicator in the analyte. There was an air bubble in the buret tip. The buret tip is leaking titrant into the analyte. The analyte solution is being stirred too quickly.
There is not enough indicator in the analyte.
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 ___________ Solution of known concentration that is slowly added to a solution of unknown concentration________ Glassware that allows a solution to be precisely and slowly added to another solution__________ When the required amount of one solution has been added to the second solution to complete the reaction_____________ A reagent added to the analyte solution that changes color when the reaction is complete____ Solution of an unknown concentration that has another solution slowly added to it_________
Titration Titrant Buret Endpoint Indicator Analyte
Identify the factors that affect the intensity of radiation detected from a radioactive source. Select one or more: The color of the source Type of emission from the source Type of materials between the source and the detector Distance of the detector from the source
Type of emission from the source Type of materials between the source and the detector Distance of the detector from the source
What is the main precaution to take if a Gas Cylinder sign is present in the lab? Select one: Visually check that the gas cylinder is restrained but keep a safe distance from it. Remove the strap from around the gas cylinder to use it in the lab. Open the valve on the gas cylinder periodically to release pressure. Test out the regulator on the gas cylinder to make sure it is working properly.
Visually check that the gas cylinder is restrained but keep a safe distance from it.
The radiation given off by a radioactive source can be measured with __________. The weak radiation should be recorded in units of _____________ because the lab sources are extremely low on the ____ scale. Radiation is a random event so it is best to make each measurement ________.
a Geiger counter, counts per minute, Curie, multiple times
When testing the pH of a solution with litmus paper, dip __________ in the solution. Add a ________ of the solution to the paper. Observe the _______ of the litmus paper and determine whether the solution is acidic or basic.
a stirring rod, drop, color
Biuret test shows the presence of A positive Biuret test appears as A negative Biuret test appears as
a tripeptide or larger peptide a violet solution a blue solution
The ninhydrin test shows the presence of ______ A positive ninhydrin test appears as_______ A negative ninhydrin test appears as___
amino acids a color change to purple a colorless solution
A neutralization reaction is a reaction between ________ that results in the formation of______ and ___________.
an acid and a base, water, a salt
In the titration setup in lab, the buret will be filled with _____________. During the titration, a beaker placed underneath will contain __________ and __________,
base, acid, indicator
Aspirin is usually packaged with ______ to reduce its ______ and the related _______
buffering agents, acidity, stomach irritation
When an alarm sounds in the laboratory, it is important to respond_____ and remain _______. List for any other instructions, turn off any _____________ in use, and be prepared to leave immediately.
calmly, quiet, equipment
Identify the term that corresponds to each definition. A method used to separate components of a mixture ______ The substance to which the sample is bound at the start of an experiment________ 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__________
chromatography stationary phase Rf mobile phase
When using acids and bases, note that these substances are________ . Make every effort to avoid contact with___________. Be sure to wipe up any spills
corrosive, the skin and lab surfaces, immediately
A hydrometer is the general name for a tool used to measure the _______ of a liquid relative to that of ________
density, water
In general, alcohols ________ when mixed with water because the _________ in alcohols can _________ water.
dissolve, O-H Bonds, hydrogen bond with
Iron(III) chloride can be used to assess the purity of aspirin synthesized from salicylic acid. Iron(III) chloride ______ react with aspirin because the reaction requires ____________________ which is present in ____________.
does not, a phenolic functional group, salicylic acid but not aspirin
Gamma rays and visible light are both ________ but gamma rays have _____ than visible light.
electromagnetic radiation, more energy
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
The heat energy absorbed or released during a chemical reaction is known as _________, or ΔH. A reaction that is exothermic, or releasing energy, will have a ΔH value that is __________. A reaction that is endothermic, or absorbing energy, will have a ΔH value that is ____________
enthalpy, negative, positive
Saponification is the process of making soap from ________. The reaction is a type of_________that uses the addition of a _________ to release the ___________, which is the soap.
fats or oils, hydrolysis, strong base, deprotonated fatty acid.
In a lab experiment, gold was found to have a density of 19.3 g/cm3 and zinc was found to have a density of 7.13 g/cm3, ______ has a higher mass per unit volume. At constant volume, density is ________ proportional to mass.
gold, directly
Changing gloves will often minimize the spread of chemicals. To properly remove gloves, first, __________, and then, __________, Then insert a __________ 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
Predict the products of hydrobromic acid, HBr reacting with magnesium hydroxide, Mg(OH)2 .
h20 MgBr2
Identify the term that matches each description: Energy that is transferred from one object to another _________ The energy needed to raise the temperature of 1 gram of a substance by 1°C_________________ A measure of the amount of thermal energy in an object___________
heat, specific heat, temperature
In comparison to other water, hard water contains more ________________________________ which react with soap to form ________________________.
heavier metal ions, such as calcium, insoluble salts called soap scum.
Choose the most appropriate task for each pictured piece of glassware.
holding an approximate volume of liquid containing a stirred reaction mixture measuring out a volume of liquid
When a vinegar and oil salad dressing separates into two layers, the oil floats on top of the vinegar. The density of the oil _________the density of the vinegar.
is less than
Seliwanoff's test distinguishes the presence of ___________ in a carbohydrate sample. A Seliwanoff's test resulting in a red solution indicates the presence of________ A Seliwanoff's test resulting in a light pink solution indicates the presence of________
ketoses and aldoses a ketose an aldose
Determine the best way to deal with each of the following items that may dangle into the way during lab work: loose bracelets long hair long earrings long necklaces flowy sleeves
loose bracelets: remove long hair: tie back or secure long earrings: remove long necklaces: remove flowy sleeves: tie back or secure
Fructose is an example of a 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 ___________ functional group. Fructose can combine with glucose to form sucrose. Therefore, sucrose is a________.
monosaccharide, 6 a ketone disaccharide
To see amino acids on a developed chromatography paper or plate, you can react it with _____________ after ______________
ninhydrin , letting the paper dry
Complete the sentences by identifying the correct missing words. Alph and beta particles originate from the ________. Protection from radiation is necessary because if radiation passes through the body it can damage ______________. Exposure to radiation can be limited by increasing the _______________ from the radioactive source.
nucleus, cells, distance
Jones's test, also known as the chromic acid test, shows the presence of_______________ A positive Jones's test appears as________ A negative Jones's test appears as_________
primary or secondary alcohols a color change to green an orange solution
Benedict's test shows the presence of: A positive Benedict's test appears as: A negative Benedict's test appears as:
reducing sugars a reddish precipitate a blue solution
Determine the type of alcohol corresponding to each given description or name. An alcohol with two other carbons attached to the carbon with the hydroxyl group: 3-ethyl-3-pentanol: 1-pentanol: An alcohol with one other carbon attached to the carbon with the hydroxyl group: 2-hexanol: An alcohol with three other carbons attached to the carbon with the hydroxyl group:
secondary alcohol tertiary alcohol primary alcohol primary alcohol secondary alcohol tertiary alcohol
Move to the safety shower if you spill hazardous chemicals on your______. Stand under the shower and _______ the lever. Remove clothing and continue flushing the area for_____.
skin or clothing, pull, 15
Identify the equipment best suited for extinguishing each type of fire. small benchtop fire: clothing fire: large fire on floor:
small benchtop fire: overturned beaker clothing fire: fire blanket large fire on floor: fire extinguisher
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
The iodine test shows the presence of: A positive iodine test appears as: A negative iodine test appears as:
starch a colar change to blue-black a yellowish solution
When taking a measurement with a pH meter, keep the instrument in the __________ until it is needed. Rinse the pH meter with ______________ and gently pat dry. Place the meter in the sample solution, and record the measurement when the pH.
storage solution, deionized water, stabilizes
Identify the level of protein structure matching each description. Overall 3D shape of a protein Interaction of multiple of protein units The sequence of amino acids Small 3D features determined by hydrogen bonding
tertiary structure quaternary structure primary structure secondary structure
When working with chemicals that are corrosive, it is particularly important to minimize the risk of contact with ____________. Proper personal protective equipment includes__________ and ____________.the body, lab surfaces, or other materials
the body, lab surfaces, or other materials, gloves, safety goggles
When filling a buret for a titration, first adjust the buret in the clamp so that _______ . Then, ____________ to add the titrant into the buret. The titrant should be filled _____________.
the opening is near eye level, use a funnel, almost to the zero mark
To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the ________ of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the __________ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from ______.
top, bottom, eye level
When sucrose is hydrolyzed,___________will be created as the glycosidic linkage is broken. Hydrolyzed sucrose _______ give a positive Benedict's test. Hydrolysis can be achieved by adding___________.
two reducing groups, will, strong acids or enzymes
