chem 101 lab final review
Some learning objectives of "Experiment 7: Beer's Law" are: A. To understand the quantitative relationship between the concentration of a light-absorbing solute and the amount of light absorbed. B. To decide on a favorite color. C. To learn how to use a calibration curve, in this case, to determine the concentration of a light-absorbing compound. D. To see how far a light source shines in the dark.
A. To understand the quantitative relationship between the concentration of a light-absorbing solute and the amount of light absorbed. C. To learn how to use a calibration curve, in this case, to determine the concentration of a light-absorbing compound.
According to the Safety Data Sheet (SDS) for 6 M hydrochloric acid (HCl), what is its Hazardous Materials Identification System (HMIS) health hazard rating?
3 (Serious Hazard: This material causes major injury upon contact unless prompt remedial action is taken and medical treatment is given.)
Please look up the Safety Data Sheet (SDS) for Silver Nitrate (AgNO3). Match the correct health hazard rating with one of the hazard statements from the SDS.
3, Corrosive, can cause skin burns and irritation.
A temperature probe will be submerged in the solvent for
30 seconds
As set by the World Health Organization (WHO) and the Food & Agriculture Organization (FAO), the Acceptable Daily Intake (ADI) of Allura Red AC is 7 mg/kg/day. For a 70 kg person, how many grams of Allura Red AC are acceptable to consume in one day?
90mg
What is the difference between a continuous spectrum and line spectrum?
A continuous spectrum contains all the wavelengths in a given range whereas the line spectrum contains only a few wavelengths.
For Reaction A (the decomposition of hydrogen peroxide catalyzed by yeast), what is the purpose of removing the foam that forms from the yeast reacting with the hydrogen peroxide?
A. Allows yeast to react with air. B. To prevent foam from being collected in the pipette bulb. C. Allows for gas to escape easier.
By measuring absorbance as a function of concentration, we can do which of the following? A. Confirm the validity of Beer's Law. B. Determine the concentration of an unknown solution. C. Black Body Radiation.
A. Confirm the validity of Beer's Law. B. Determine the concentration of an unknown solution.
Which of the following processes for disposing of liquid waste containing hazardous material is incorrect? (Select all that apply.) I. Bring the waste to the liquid waste bottle in the fume hood. II. Check the liquid level in the waste bottle. If the level is within 2" of the neck of the bottle, notify your TA so that the bottle won't be overfilled. III. Bring the liquid waste bottle and funnel to your bench. IV. Check the liquid level in the waste bottle. As long as the liquid is not yet into the funnel, proceed. V. Read the label on the waste bottle to be sure it is meant for the correct experiment and the correct waste material. VI. Open the latch, lift the funnel cover out of the way, and pour the waste material into the funnel. VII. Close the funnel lid until the latch snaps into place. VIII. Close the funnel lid most of the way. It is okay to leave it unlatched if other students will soon be using the waste container.
A. IV, III, VI, VII C. V, IV, I, VI, VIII E. III, V, IV, VI, VII F. VI, VII
Important PPE for this lab includes A. Lab coat B. Close-toed shoes C. Goggles (to be worn at all times in the lab space) D. Gloves (to be worn at all times manipulating the experimental set-up) E. Gloves (to be worn at all times even on a computer)
A. Lab coat B. Close-toed shoes C. Goggles (to be worn at all times in the lab space) D. Gloves (to be worn at all times manipulating the experimental set-up)
When dealing with hazardous materials generated in the lab, the two most important guidelines are: (Choose two.) A. Organize the experiment to generate the least amount of hazardous material possible. B. Never dispose of anything without asking your TA for assistance. C. Materials used in General Chemistry are generally nonhazardous, so most can go in the normal trash. D. Collect ALL hazardous material for proper disposal. E. When in doubt, dispose of materials as though they are the most hazardous type to be safe.
A. Organize the experiment to generate the least amount of hazardous material possible. D. Collect ALL hazardous material for proper disposal.
According to the Safety Data Sheet (SDS) for iron(II) sulfate, what personal protective equipment (PPE) are needed for safe handling? (Select all that apply.) A. Protective Clothing B. Gloves C. Safety Goggles D. Clean-room suit E. Respirator; if exposure limits are exceeded F. Face Shield
A. Protective Clothing B. Gloves C. Safety Goggles E. Respirator; if exposure limits are exceeded
Which instruments will be used in this lab to record photoluminescence (i.e., emission of light)? (Select all that apply) A. Spectroscope B. Spectrometer with optic cable C. Colorimeter D. Buret
A. Spectroscope B. Spectrometer with optic cable
For the determination of an unknown concentration during this experiment, why should the absorbance of your samples fall in the middle of your calibrated range (Absorbance ~ 0.5 - 0.7)? A. To use the most accurate portion of the calibration curve B. It shouldn't C. For the most accurate concentration determination
A. To use the most accurate portion of the calibration curve C. For the most accurate concentration determination
Some learning objectives of "Experiment 5: Gas-Forming Reactions & Rockets" A. To learn about the combustion reaction that propels the rocket. B. To understand the role of a catalyst in a chemical reaction. C. To make warm salt water. D. To learn about two chemical reactions that produce gas.
A. To learn about the combustion reaction that propels the rocket. C. To make warm salt water. D. To learn about two chemical reactions that produce gas.
The following items are part of the experimental set-up when collecting data. Select all that apply. A. Vernier Graphical Analysis B. Stir Bar C. Paper Clip D. Binder Clip E. Solvent F. KimWipe G. Vernier Spectral Analysis H. Vernier Temperature Probe I. Receiving beaker to catch excess solvent
A. Vernier Graphical Analysis D. Binder Clip E. Solvent F. KimWipe H. Vernier Temperature Probe I. Receiving beaker to catch excess solvent
Beer's law gives the mathematical relationship between solution concentration and absorbance. According to Beer's law, the experimentally determined values of absorbance (A) are given by multiplying: (Select all that apply) A. c, the concentration of the solution. B. ε, the molar extinction coefficient (also called molar absorptivity). C. l, the path length of the cuvette. D. t, the amount of time in the light beam
A. c, the concentration of the solution. B. ε, the molar extinction coefficient (also called molar absorptivity). C. l, the path length of the cuvette.
In the absence of scattering or reflection, light directed toward a colored solution is either transmitted (light passes straight through) or is:
Absorbed by the solution.
In this experiment, why is the mass of the buret segment with water measured twice for each sample; once before and once after heating?
The second measurement accounts for mass loss due to evaporation
A Beer's law calibration curve has absorbance (y-axis) plotted as a function of solution concentration (x-axis.) A fit of the data should give a line with a slope equal to:
ε*l, which is the molar extinction coefficient multiplied by the pathlength
With c defined as the speed of light, and h as Planck's constant, what is the relationship between wavelength (λ) and the energy of a photon (∆E)?
∆E=hc/λ
Balance the molecular equation for the combustion reaction between hydrogen and oxygen, __H2 (g) + __O2(g) → __H2O(g). by selecting the correct coefficients. (For the choices below, the coefficients correspond to the chemical species in the order these appear in the reaction, e.g., first coefficient corresponds to H2(g), etc.)
2, 1, 2
The balanced molecular equation for the reaction between zinc and hydrochloric acid is Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g). Select the correct net ionic equation below.
2H+ (aq) + Zn(s) → H2(g) + Zn2+(aq)
The main purpose for Experiment 4: Intermolecular Forces is to...
... determine how molecular structure and molecular weight of molecules influence the intermolecular forces between molecules and the enthalpies of vaporization.
In some circumstances, using the fire extinguisher found in the laboratory may be necessary. Which of the following scenarios represents an appropriate use of a fire extinguisher?
A handful of paper towels in the garbage can has caught fire. The fire is small and relatively contained within the trash can.
For Reaction B (oxidation-reduction reaction between zinc and hydrochloric acid), why should you not create a seal between the pipette bulb and the tubing when collecting H2 gas? A. In order to allow water to be displaced by gas. B. To prevent an explosion from occurring. C. To prevent the pipette bulb from popping off of the tubing. D. All of the above.
All above
For which of the following situations should you be sure to notify your TA and fill out an incident report form? (Check all that apply.) A. During check-in you discover a broken funnel in your drawer, and the broken end of the stem causes a small nick through your glove. Feedback: No matter how small the injury, you should report it to your TA and be sure to wash the area thoroughly to be sure you have washed away any potential contamination. B. You arrive in lab, but realize that your cold medicine is making you feel groggy.Feedback: Even though the cause of this issue did not originate in lab, it is important that your TA knows and that an incident report is filed. In this case, your TA would recommend an excused absence. You should never attend lab if you have medication or other substances in your system that impair your awareness or ability to function in lab. If you shouldn't drive, you shouldn't come to lab. C. You begin to feel faint and dizzy in lab because you had to skip lunch.Feedback: Even though the cause of this issue did not originate in lab, it is important that your TA knows and that an incident report is filed. In this case, your TA would recommend that you take a breat to get water and/or a snack. The lab is a terrible place to faint. You should never attend lab if you have an illness or medical condition that would impair your awareness or ability to function in lab. If you shouldn't drive, you shouldn't come to lab. D. During lab check-out at the end of the semester, your lab partner accidentally drops a beaker, and a small chip of glass causes a scratch on your ankle because you weren't wearing socks.Feedback: No matter how small the injury, you should report it to your TA and be sure to wash the area thoroughly to be sure you have washed away any potential contamination. E. You accidentally pick up a beaker from the hot plate, not realizing that it was already hot, and the edge of the beaker leaves a small red mark on your thumb.Feedback: No matter how small the injury, you should report it to your TA and be sure to wash the area thoroughly to be sure you have washed away any potential contamination.
All of the above
For which of the following situations should you be sure to notify your TA and fill out an incident report form? (Check all that apply.) A. While waiting in the lab room for a friend to finish. B. As soon as you enter the lab, and until you are ready to walk out the door. C. During the lab quiz. D. While cleaning up after experimental work is done. E. Once the experimental work has begun.
All of the above
Which of the following is a behavior that can pose a safety risk in the laboratory environment? A. Looking away from your work to answer a question from your TA or lab partner. B. Moving rapidly around the lab to be sure to finish the experiment in time. C. Leaving your lab drawer open while you set up your apparatus and obtain your reagents. D. Staying focused on your own experiment and not being distracted by what nearby groups are doing. E. Sitting on lab benches, lab floors, or hallway floors, while waiting for lab to begin or for another student to finish.
All of the above
Which of the following precautions is important when using a hot plate? (Check all that apply.) A. Set up the work space so that flammable materials - notebooks, paper towels, other reagents, etc. - are far away from the hot plate to prevent them coming in contact with the hot surface. B. Never leave the hot plate turned on an unattended. C. Remember that the ceramic top of the hot plate, and any glassware heated by the hot plate will look the same when hot as cold, and will not cool down until well after the hot plate has been shut off. D. Set up your work space so that wires and cables cannot accidentally make contact with the ceramic surface and melt. E. Set up your work space with the hot plate in a secure location away from the edge of the bench so that you won't accidentally bump it and spill hot or flammable liquids.
All of the above
Which of the following explains why the lab safety policy specifically addresses loose clothing and large, loose, or dangling jewelry? A. Loose clothing and jewelry is more likely to impede movement, or accidentally knock materials over, causing a spill or other accident. B. Loose clothing or jewelry is more likely to present a fire hazard if open flames are used in the lab for any reason, or if a fire begins accidentally. C. In the event of a spill or spray of reagent, these items are likely to hold the chemical close to the skin, making it harder to remove and therefore increasing the risk of injury. D. Contact with chemicals in the lab might damage these items. E. All of these answers are true.
All of these are true
When the procedure calls for making a more dilute solution of an acid, or mixing an acid with other solutions, what is the correct order of steps?
Always Add Acid - Either add all of the water or non-acid component first, or add a significant portion, before adding the acid to the mixture. This helps to minimize the heat generated, which could otherwise create dangerous fumes or reactions.
During emission, a photon is emitted as there is a loss in energy of what?
An electron
A combustion reaction is: A. A reaction that occurs spontaneously. B. An oxidation-reduction reaction that uses oxygen and releases energy in the form of heat and/or light. C. A reaction in which oxygen burns. D. A reaction that perpetually continues with no outside driving force.
An oxidation-reduction reaction that uses oxygen and releases energy in the form of heat and/or light.
How many times should you read the label on a reagent container and compare it with the lab manual?
At least twice each time you remove material from the container.
Your lab partner accidentally gets a mist of your solution in her eye. You immediately help her to the eye wash to rinse it. After about a minute, she feels better and is ready to get back to work. You should: A. Stay under the shower until the shirt has been completely rinsed. B. Remove your shirt and any other clothing that were in contact with the chemical. C. Stay under the shower for at least 15 minutes. D. Check the Safety Data Sheet to be sure you should be removing your clothes in a public space.
B. Remove your shirt and any other clothing that were in contact with the chemical. C. Stay under the shower for at least 15 minutes.
The learning objectives of "Experiment 1: Mass, Volume, and Density" are: (Select all that apply.) A. To determine why water is important in the laboratory. B. To establish laboratory skills needed for high-quality measurements by measuring the density of water at room temperature. C. To develop an understanding of precision and accuracy in the laboratory environment by examining the effects of temperature on density. D. To distill and purify water for use in future laboratory periods.
B. To establish laboratory skills needed for high-quality measurements by measuring the density of water at room temperature. C. To develop an understanding of precision and accuracy in the laboratory environment by examining the effects of temperature on density.
If you need to work with a flammable or volatile solvent, which piece of lab equipment should you be sure NOT to use?
Bunsen or Meker burner, or anything with an open flame.
Select the answer with the correct number of significant figures for 0.34 x 8.27.
C. 2.8
What instrument are we using to collect our data measurements this week?
Conductivity Probe
According to the Safety Data Sheet (SDS) for mossy zinc, which of the following is listed under the "Hazards Identification" section?
Corrosive
If the mass of your sample remains the same, but your volume increases, how does this influence the density of the sample?
Decrease
What property of water is often used to initially evaluate purity of water samples?
Density
To make the rocket fly, O2 and H2 react together. How do you determine the degree of combustion?
Distance the rocket flies
This clothing would be appropriate for lab.
False
This shoe would be appropriate for lab.
False
When discussing intermolecular forces, electronegativities of atoms in molecules are not important.
False
Water has a density of 1.00 g/mL. Three sets of density measurements of water are shown in the table below. Use Excel to calculate the mean and standard deviation (std. dev.) for each data set, then select the data analysis table that shows the correct values.
For Set A (g/mL): A mean of 1.02 and a Standard Deviation of 0.03 For Set B (g/mL): A mean of 1.61 and a Standard Deviation of 0.04 For Set C (g/mL): A mean of 1.97 and a Standard Deviation of 1.25
When should you inspect the glassware in your lab drawer for chips, cracks, or chemical residues?
Glassware should be inspected at all of these times to prevent accidents, injuries, or unwanted complications during experimental work.
How are electrons excited in the flame test?
Heat from the flame
Order the following steps you would take if you find broken glassware in your lab drawer, or if a piece of glassware breaks during the lab. I.Use a pair of leather gloves found in the lab room to prevent nicks or cuts. II. Clean up large pieces and dispose of in the designated glass only waste container. III. Notify your TA so that they can help you. IV. Use the dustpan and brush found in the lab room to sweep up small shards and chips in the area where the glassware was broken and dispose of these in the designated glass waste. V. Pick up large pieces immediately, using the regular lab gloves. VI. Do nothing else. The TA will clean up all broken glass.
III, VI
What is the objective of this lab? A. Identify composition of unknown metal mixture based on emission spectra. B. Learn about what constitutes incandescent lights. C. Relate emission spectra to quantitative frequency, wavelength and energy. D. Use a spectroscope to observe and compare continuous emissions and line emissions from various sources. E. Determine how to light a Bunsen burner.
Identify composition of unknown metal mixture based on emission spectra. Relate emission spectra to quantitative frequency, wavelength and energy. Use a spectroscope to observe and compare continuous emissions and line emissions from various sources.
The Balmer equation is shown here: ∆E = RH (1 /(n2f) − 1/( n2i)), where RHis the Rydberg constant This equation calculates the energy difference between which of the following?
Initial and final energy states of an electron
Your lab partner accidentally gets a mist of your solution in her eye. You immediately help her to the eye wash to rinse it. After about a minute, she feels better and is ready to get back to work. You should:
Keep her in the eye wash for at least 15 minutes, and then make sure she goes to student health, just to be sure.
According to the Safety Data Sheet (SDS) for hydrogen peroxide (H2O2), which of the following is listed as a hazard statement?
May cause fire or explosion; strong oxidizer.
Why is it important to prevent mixing of the hydrogen peroxide with the zinc/acid mixture in the waste container? (For the safety of all involved, if you do this incorrectly in the lab, you will lose all of your in-lab points.)
Mixing of hydrogen peroxide and zinc/acid in the waste container will form Cl2 gas, which is poisonous.
When reading the label on a reagent container, what are the three most important pieces of information?
Name, Hazard warning(s), concentration
How many decimal places beyond the markings of the instrument should one estimate when taking a reading?
One
Which of the following must be completed as soon as you arrive in lab?
Put on your goggles. Store your backpack, cell phone, jacket, and all other nonessential items in designated storage areas. Put on your lab coat. Tie back long hair.Tie back long hair.
What is the advantage of pooling your data with the rest of the lab section?
Reduces the effect of random error.
From the data sets of question 11, which data set is the most accurate?
SET A
From the data sets of question 11, which data set is the most precise?
SET A
What is your BEST resource for understanding the nature of the chemical hazards of materials you work with in lab?
Safety Data Sheets (SDS) that should be consulted before coming to lab each week.
Please look up the Safety Data Sheet (SDS) for Lithium Chloride (LiCl). Match the hazard statement with a safety precaution you can use against that hazard.
Skin irritant. Wear nitrile gloves and eye protection at all times.
What instrument will be used during this experiment to measure absorbance?
Spectrophotometer
Assuming the absorption profiles are the same for Gatorade and Powerade used during this experiment, if a Powerade solution appears darker than a Gatorade solution, which of the following is true?
The Powerade solution is more concentrated.
What would happen if you did not use a stopper in Reaction A (the decomposition of hydrogen peroxide catalyzed by yeast)?
The gas would escape and would not be collected.
Consider each of the samples of water used in this experiment. Why should you anticipate that these samples will have different densities?
They have differing amounts of contaminants.
Why should the water in the buret segment be below the level of water in the 600 mL beaker?
To ensure that all of the water in the buret is heated consistently.
For Reaction B (oxidation-reduction reaction between zinc and hydrochloric acid), why should you wait to at least two minutes after adding zinc to collect hydrogen?
To ensure the collection of pure hydrogen gas by allowing enough time so that hydrogen gas displaces the other gases in the tube.
Although goggles should always be worn in the lab, why are goggles an especially important piece of protective equipment in this experiment?
To prevent eye damage from ultraviolet light produced by various light sources.
There should NOT be any liquid waste in this lab.
True
This clothing would be appropriate for lab.
True
This shoe would be appropriate for lab.
True
True or False: Do NOT consume any substance that is opened in the lab even if the substance is otherwise potable or edible.
True
True or False: In the absence of scattering or reflection, the colors that a material or colored solution absorbs and the intensity of absorption are quantified by its absorption profile (i.e., wavelength-dependent absorption characteristics; molar absorptivity vs. wavelength).
True
True or False: Paper towels or Kimwipes stained with Allura Red AC can be thrown in the regular trash bin.
True
True or False: The scale (0-10) on the spectroscope is arbitrary and must be calibrated against a source of known wavelengths.
True
True or false: Yeast catalyzes the decomposition of H2O2 to produce gas.
True
Which of the following items are not allowed in the lab space during lab, but must be stored in appropriate locations?
Water bottle, food or snacks, cell phone
In some circumstances, materials that are being heated in the lab could catch fire. If a flammable substance in a beaker should catch fire while you are working but the flames are relatively contained, what is a simple method for extinguishing the flame?
Turn off the heat source immediately, and use a watch glass to cover the beaker and minimize the oxygen
What is the purpose of the lab?
Using stoichiometry in order to confirm the Law of Conservation of Matter through a titration experiment.
What is the most important consideration to preserve safety when it is necessary to feed glass tubing, thermometers, or other apparatus through a rubber stopper?
Using the correct hand position so that if something goes wrong you can avoid coming into contact with broken or sharp ends.
Which of the following steps in the correct procedure for lighting and working with a Bunsen burner is incorrect? I. Make sure all loose clothing and hair have been properly restrained and will not contact the flame accidentally. II. Prepare the work space to be sure no flammable materials are in the vicinity of the open flame. III. Inspect the tubing to the gas valve to be sure it does not have any cracks or holes that would allow a gas leak. IV. Inspect the burner to be sure that the air intake and fuel valves move properly and can be adjusted. V. With the sparker in hand, turn on the gas and light the flame as soon as possible to minimize unburned gas in the air. VI. Adjust the fuel valve to set the height of the flame and adjust the air intake to adjust the temperature (color) of the flame, according to the instructions in the lab manual. VII. Adjust the fuel valve to set the temperature (color) of the flame and adjust the air intake to set the height of the flame, according to lab manual instructions. VIII. Monitor the flame and all nearby materials closely until the experiment is complete. Never leave an open flame unattended.IX. Shut off the burner and gas valve as soon as experimental work is completed (or anytime you must leave it unattended).
VII
All of the following are the main types of intermolecular forces which pure solids can possess except:
Van der Waals forces
When should you be sure to use a sealed container and/or secondary containment in the laboratory?
When transporting materials from one lab room to another.
For which of the following should gloves be used in the laboratory?
When using reagents, even nonhazardous materials. Handling glassware, even without any reagents present. When cleaning up the bench, after the experiment is over.
According to the Safety Data Sheet (SDS) for calcium hypochlorite, is it possible for this substance to cause serious damage if it gets in the eyes?
YES
Do all laboratory instruments require calibration for proper use?
YES
Using the color wheel provided in the background information of experiment 7, what color does a violet eggplant absorb?
Yellow
In this lab, the color of light emitted from a source is measured. Is the color of light related to the energy of the photons (elementary light particles)?
Yes, blue-colored photons have more energy than red ones
How many seconds can a flame be left unattended in this experiment?
Zero (it should never be left unattended)
For the two gas-producing reactions included in this experiment, which of the following correctly pairs the reactants with the corresponding gas products?
Zn and HCl yields H2; decomposition of H2O2 catalyzed by yeast yields O2
The solvent soaked Kimwipes will be discarded
in the solid waste containers inside the chemical fume hoods
What are the SI units for density?
kg/m3
The balanced molecular equation for the reaction between zinc and hydrochloric acid is Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g). During this reaction, zinc undergoes:
oxidation
In this lab, we will be measuring
temperature as a function of time
As part of conceptual understanding and the data acquisition, we will be able to see the direct relationship of
total temperature change and molecular properties
