Chem 102L Final
What is the equilibrium concentration (M) of iron thiocyanate in this reaction given the values provided?
9.78 x 10^-5 M
Exp 15.1: This reaction can be monitored informally by the color formation because A. The starting materials are mostly colorless and the the product, iron thiocyanate, is colored B. the starting materials are colored and the product, iron thiocyanate, is colorless C. the starting materials and the product are colored D. other
A
Exp 15.2: The lamba max needed to solve for the equilibrium concentration of iron thiocyanate is A. the same from 15.1 B. has to be calculated based on the spectrophotometer absorbance for 15.2 C. 350 nm
A
Exp 16.1 The inflection point is the greatest change in slope along the acid/base titration curve. The first derivative plot peak A. corresponds to the region of greatest slope, therefore an equivalence point in the titration curve. B. corresponds to the amount of titrant added to the titration. C. corresponds to the starting pH of the solution. D. corresponds to the volume needed to reach a pH of 7.
A
Exp 16.2: It is important to have proper technique in addition of the titrant to A. ensure all equivalence points can be observed. B. ensure only parts of the solution are being neutralized. C. ensure the reaction is making only products. D. proper technique is not necessary.
A
In experiment 12, we will be measuring A. Temperature as a function of time B. Temperature as a function of volume C. Temperature as a function of viscosity D. Temperature as a function of volts
A
My most important role in lab is A. working safely. B. learning all the techniques. C. writing excellent lab reports. D. arriving to lab on time.
A
This liquid sample would experience the largest temperature change.
A
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? A. 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. B. Always Add Acid - the acid should be added first and then the other materials to prevent a dangerous reaction. C. Neither of these methods is safe.
A
Which of the following has a greater enthalpy of vaporization?
A
When should you NEVER use a sealed container ? A. When transporting materials from one lab room to another. B. When transporting materials from the hood to the bench. C. When heating a solution over a hot plate, burner, or heating mantle.
C
When should you inspect the glassware in your lab drawer for chips, cracks, or chemical residues? A. During an experiment, before using any piece of glassware. B. Before beginning every experiment. C. Glassware should be inspected at all of these times to prevent accidents, injuries, or unwanted complications during experimental work.
C
When working in the lab, you should always remove your gloves when: I. Typing on your laptop keyboard II. Leaving the laboratory II. Picking up your pen to record observations in the lab notebook IV. Using the doorknob V. Using the laboratory phone A. Only I. and II. are correct B. All but III. are correct C. All of these are cases when you should first remove your gloves D. Only II. is correct
C
Which of the following is the reason backpacks must be stored during lab? A. Backpacks on the floor of the lab or on the benches may be exposed to hazardous materials, which might then lead to student exposure outside the lab. B. Backpacks on the floor present a tripping hazard to students in lab, which may lead to spills and other incidents. C. Both of these are good reasons to keep nonessential items stored properly.
C
Which of the following statements is FALSE when it comes to working with hot glassware? A. When handling hot glassware, be sure to use the silicone or rubber "hot hand" provided to prevent burns. B. If you receive a small burn on your hand, you should immediately notify your TA and run cold water of the burn. C. To check if a piece of equipment is hot, quickly touch it, but do not hold your finger in place to prevent burns. D. NEVER TOUCH HOT GLASSWARE!
C
What is your BEST resource for understanding the nature of the chemical hazards of materials you work with in lab? A. Your TA, or your instructor you visit during office hours. B. The label on the reagent bottles found in the fume hood. C. Safety Data Sheets (SDS) that should be consulted before coming to lab each week.
C.
Exp 12: As part of conceptual understanding and the data acquisition, we will be able to see the direct relationship of A. total temperature change and solvent conductivity B. solvent conductivity and viscosity C. enthalpies of vaporization and names D. total temperature change and molecular properties
D
What is the change in concentration (M) of iron nitrate nonahydrate in this reaction?
-9.78 x 10^-5 M
The proper process(es) for disposing of liquid waste containing hazardous material could be: A. Bring the waste to the liquid waste bottle in the fume hood. 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. B. Bring the liquid waste bottle and funnel to your bench. Check the liquid level in the waste bottle. As long as the liquid is not yet into the funnel, proceed. C. Open the latch, lift the funnel cover out of the way, and pour the waste material into the funnel. 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, B
Your lab partner accidentally trips and douses the front of your lab coat and shirt with a hazardous material. The TA immediately takes you to the safety shower, since the spill has soaked into your clothing. What do you need to do at this point? Check all that apply. A. Stay under the shower for at least 15 minutes. B. Remove your shirt and any other clothing that were in contact with the chemical. C. Stay under the shower until the shirt has been completely rinsed.
A, B
When dealing with hazardous materials generated in the lab, select all the guidelines that are applicable: A. Collect ALL hazardous material for proper disposal. B. Organize the experiment to generate the least amount of hazardous material possible. C. When in doubt, dispose of materials as though they are the most hazardous type to be safe. D. Materials used in General Chemistry are generally nonhazardous, so most can go in the normal trash.
A, B, C
Exp 12: The following items are part of the experimental set-up when collecting data. Select all that apply. A. Vernier Temperature Probe B. Solvent C. Kim wipe D. Sitr Bar E. Vernier Graphical Analysis F. Vernier Spectral Analysis G. Paper Clip H. Binder Clip I. Receiving beaker to catch excess solvent
A, B, C, E, H, I
Exp 15.1: You will be using all of the following equipment in some capacity in this lab. Select all that are applicable. A. 10-mL volumetric flask with a yellow plastic cap B. Beaker C. Erlenmeyer flask D. Scintillation vials E. Cuvettes F. Glass pipettes G. Plastic transfer pipettes H. Micropipettes I. Micropipette tips
A, B, D, E, G, H, I
When should you immediately turn off the gas valve for a Bunsen or Meker burner? Check all that apply. A. :If you must leave the open flame unattended and there is no one else to monitor it. B. Only at the end of lab when everyone has completed the experiment. C. If you smell gas in the room. D. If the flame suddenly goes out.
A, C, D
Exp 15.1: Temperature is NOT a factor we will be considering this class period. However, the reaction in question is an exothermic reaction. Select all of the following conditions that will perturb the reaction to proceed in the forward direction. A. adding more reactant B. adding more product C. adding more heat D. removing heat E. adding an inert gas
A, D
Exp 15.2: Last time, you determined two important quantities for [Fe(NCS)]^22^++, what were these two quantities? A. lambda max B. color of starting materials C. color of product D. molar extinction coefficient E. pH of nitric acid used to make the starting material F. pka of the products
A, D
Exp 16.1: The following characteristics define what a primary standard is. Select all that apply. A. High in purity B. Low in purity C. Insoluble in water D. Soluble in water E. Unstable in air F. Stable in air G. Dries readily H. Has quantitative reactivity with the substance to be standardized I. Reacts only partially to the substance being standardized J. Has a detectable equivalence point with high accuracy K.Doesn't have an equivalence point
A, D, E, F, G, H, J
When reading the label on a reagent container, what are the three most important pieces of information? A. Chemical formula B. Concentration C. CAS Number D. Hazard warning(s) E. Color F. Name
A, D, F
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? A. Turn off the heat source immediately, and use a watch glass to cover the beaker and minimize the oxygen around the flame. B. Use the chemical fire extinguisher located in the lab. Pull the pin, aim the nozzle into the beaker, and pull the lever. C. Use water from the sink nearest the bench to douse the flames.
A.
For which of the following situations should you be sure to notify your TA? Check all that apply. A. You begin to feel faint and dizzy in lab because you had to skip lunch. B. 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. C. You arrive in lab, but realize that your cold medicine is making you feel groggy.
All of the above
If any chemical makes contact with your hand, you should A. Remove your glove. B. Put your hand under running cold water for 15 minutes. C. Contact your TA. D. Fill out an incident report.
All of the above
When should you be sure to wear full PPE (proper attire, lab coat, goggles) in the laboratory? (Check all that apply.) A. While cleaning up after experimental work is done. B. While waiting in the lab room for a friend to finish. C. As soon as you enter the lab, and until you are ready to walk out the door. D. Once the experimental work has begun.
All of the above
Which of the following must be completed before the pre-lab lecture in lab? Select all that apply. A. Put on your lab coat. B. Store your backpack, cell phone, jacket, and all other nonessential items in designated storage areas. C. Tie back long hair. D. Put on your goggles.
All of the above
Exp 16.2: Why are bubbles in the burette bad? A. The bubbles stem from using too strong of titrant so new solution must be prepared. B. It's a sign the titration is finished; they are not bad. C. It adds unnecessary error affecting the volume.
C
For Experiment 16, we are running a neutralization reaction. The titrant is ____ and it goes in the buret; the unknown acid goes in the ____ with a stir bar. A. water; beaker B. sodium hydroxide; vial C. sodium hydroxide; beaker D. sodium hydroxide; polyethylene bottle
C
Which of the following precautions is important when using a Bunsen burner or Meker burner? Select all that apply. A. Set up your work space so that wires and cables cannot accidentally make contact with the flame or hot glassware and melt. B. Always tie back hair, even long bangs, that might accidentally come in contact with the flame. C. Set up the work space so that flammable materials - notebooks, paper towels, other reagents, etc. - are far away from the burner to prevent them coming in contact with the hot surface. D. Set up your work space with the burner in a secure location away from the edge of the bench so that you won't accidentally bump it and spill hot liquids. Remember that any glassware heated by the burner will look the same when hot as cold, and will not cool down until well after the burner has been shut off. Never leave an open flame unattended, even for a brief time.
All of the above
systematic uncertainty
An error made when there are issues with experimentation or certain equipment that is used in experiment. Often influence the measurement's accuracy within the experiment and affects them the same amount
Exp 12: A temperature probe will be submerged in the solvent for A. 10 seconds B. 30 seconds C. 45 seconds D. 60 seconds
B
Exp 15.1: The Beer's Law relationship is how we will solve for the molar absorptivity coefficient. What is the equation that translates to the linear regression format? A. A = I/I_0 B. A = m[analyte] + b C. C = Am D. C = Ae
B
Exp 15.1: What physical property of which compound are you monitoring? A. The pKa of reactant, Fe(NO_33)_33 B. The UV/Visible absorption of the product, [Fe(NCS)]^22^++ C. The UV/Visible absorption of the reactant, Fe(NO_33)_33Choice D. The UV/Visible absorption of the reactant, NaSCN
B
Suppose a beaker of solid reagent drops onto the bench and cracks. Which of the following represents the correct disposal: A. To minimize the risk of injury, all materials should be added to the glass waste. B. To the extent possible, solid reagent should be added to the solid waste container and broken glass should be added to the glass waste. Hazardous materials should never be added to the glass waste, and broken glass should only be allowed in the solid waste with the TA's approval. C. To maximize the correct disposal of hazardous material, all materials should be added to the chemical solid waste.
B
The main purpose for Experiment 15.1 is to A. Run a reaction B. Determine the relationship between the concentration of Fe(NCS)^22^++ and the absorbance to collect the value of molar absorption coefficient C. Collect absorbances and discuss the chemical equilibrium D. Solve the K value of the reactionChoice 5 of 5:To use Beer's Law to calculate the wavelength needed for spectrophotometry
B
The main purpose for Experiment 16.2 is to A. determine the time it takes for the equivalence point to be reached B. determine the pka(s) of an unknown acid and thus identify the unknown titrated C. determine the equilibrium constant for the titration D. Confirm the concentration of sodium hydroxide from 16.1
B
The proper method to load a burette with solution is A. on the bench top over the head B. at eye level (lowering the burette in the sink or acquiring a stool as necessary) C. without gloves so one can have a better grip
B
This liquid sample would experience the fastest rate of temperature change.
B
What do chemical equilibrium constants tell us about the reaction? A. The effect of temperature on the reaction B. The extent to which a reaction occurs C. The standardization of a desired solution D. The amount of moles needed to create a product
B
Which has a greater enthalpy of vaporization?
B
Which has a smaller enthalpy of vaporization?
B
Which of the following is NOT a behavior that can pose a safety risk in the laboratory environment? A. Leaving your lab drawer open while you set up your apparatus and obtain your reagents. B. Staying focused on your own experiment and not being distracted by what nearby groups are doing. C. Moving rapidly around the lab to be sure to finish the experiment in time. D. Looking away from your work to answer a question from your TA or lab partner.
B
While weighing out a reagent for use in an experiment, a student finds he has leftover reagent. The student should A. Return the excess reagent to the stock bottle to minimize the amount of waste generated. B. Place the excess reagent in the appropriate solid or liquid waste container to prevent contamination of the stock reagent. C. Notify the TA immediately. D. Leave the dispensed material out on the bench so that another group can use it, which will minimize the waste generated.
B
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 still do the following before the TA fills out the incident report: A. Keep her in the eye wash for at least 5 minutes and then let the TA decide if she can continue working. B. Keep her in the eye wash for at least 15 minutes, and then make sure she goes to student health, just to be sure. C. Check to see if her eye is still red. If not, hurry so that you can finish the experiment. D. Let the TA inspect her eye to see if it is okay.
B
Your lab partner accidentally spills some acid on his wrist and watchband. You should: Select all that apply. A. Take him to the safety shower, and make sure he stands under it for at least 15 minutes to be sure all hazardous material has been washed away. B. Let the TA inspect his wrist to see if it is okay. C. Remove the watch and watchband immediately, and rinse his wrist for at least 15 minutes to be sure all hazardous material has been washed away. D. Rinse the watch band before allowing him to put it back on.
B,C,D
All of the following are the main types of intermolecular forces which pure solids can possess except: A. Ion-dipole interactions B. Dipole-dipole interactions i.e hydrogen bonding C. Van der wick forces
C
Exp 16.1: As part of conceptual understanding and the data, we will be using the dilution equation __ to make ___ M solution of NaOH. A. M1V1 = M2V2; 1.0 B. pH = -log(H+); 1.0 C. M1V1 = M2V2; 0.1 D. pH= -log(H+); 0.1 E. other
C
The solvent soaked Kimwipes will be discarded A. in the trash. B. in the glove recycling bins/boxes. C. in the solid waste containers inside the chemical fume hoods.
C
If you choose to wear loose clothing, large or dangling jewelry, or contact lenses to lab, which of the following statements best represents how you should proceed? A. Make sure all loose clothing or jewelry can be confined by the lab coat B. Make sure to wear your goggles securely over your contact lenses and check with your lab manual and TA to be sure you will not be working with any volatile or fume-producing reagents. C. Make sure none of the jewelry will catch on your clothing or accidentally cut your gloves, and don't wear anything too valuable. D. All of these statements are reasonable compromises if you MUST wear these items to lab, but the best and safest practice is to leave them at home and dress for lab intentionally.
D
If you need to work with a flammable or volatile solvent, which piece of lab equipment should you be sure to use? A. Bunsen or Meker burner, or anything with an open flame. B. Hot plate. C. Heating mantle. D. Fume hood with good ventilation E. Volumetric flask.
D
Le Chatelier's Principle states that A. as temperature increases, the pH of a reaction also increases B. as a reaction reaches equilibrium, the K values increase C. a chemical reaction will spontaneously go to completion if enough energy is put into the system D. a chemical reaction will always restore equilibrium when perturbed
D
The main purpose for Experiment 12: Intermolecular Forces is to A. learn about safety B. Navigate through the procedure and connect the temperature probe to the computer C. Collect data and report the minimum temperature D. Determine how molecular structure and molecular weight of molecules influence the intermolecular forces between molecules and the enthalpies of vaporization
D
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? A. Using sufficient vacuum grease that the apparatus slides smoothly. B. Using sufficient force that the apparatus will slide through the stopper. C. Letting your TA handle the procedure for you. D. Using the correct hand position so that if something goes wrong you can avoid coming into contact with broken or sharp ends.
D
What should you do if you get chemicals on your gloves or they appear stained? A. Carry on with the experiment and dispose of them in solid waste at the end of the period, unless your skin is irritated B. Put on another pair of gloves over the gloves you are wearing to protect yourself from the chemicals you are working with since one layer of gloves doesn't appear to be enough C. Be sure to touch every surface in the lab D. Dispose of the dirty gloves and replace them with new ones, rinsing your hands and telling your TA if you think something particularly hazardous has permeated them or if you feel any irritation
D
Exp 16.1: How can a titration curve be defined? A. It is a plot that shows only the addition of titrant into a solution over time. B. It is a graphical description of the solution color change as the conjugate ion of the indicator is formed. C. It is used to calculate with more accuracy the equivalence point volume of the titration. D. It shows the starting pH of a solution and what happens over time upon heating. E. It is a graphical description of the solution pH as a function of the volume of added titrant.
E
If you need to leave the lab to go to the restroom, you should A. Remove your gloves and recycle. B. Remove your lab coat and hang it on the coat rack by the door. C. Ask a lab partner to watch your experiment. D. Notify your TA of your plans to momentarily leave the room. E. All of the above F. Only A and B
E
The main purpose for Experiment 16.1: Standardization of NaOH is to A. Navigate through the procedure and make no mistakes B. Learn about safety C. Determine the necessary volume needed to make 0.1 M NaOH D. Determine the volume needed to titrate an unknown acid E. Titrate an unknown concentration of NaOH with KHP (potassium hydrogen phthalate) to determine the true concentration of the NaOH
E
Exp 16.1: The following items are part of the experimental set-up when collecting data for any parts. Select all that apply. A. Vernier Temperature probe B. Vernier Conductivity probe C. Vernier pH probe D. Phenolphthalein E. Kim wipe F. Stir bar G. Vernier Graphical Analysis H. Hot plate I. Stir plate J. Beaker or flask containing K. dissolved KHP L. Burette M. Burette clamp
E, F, G, I, J, K L
Exp 16.2: A student weighed out KHP using the weigh-by-difference technique. They weighed the KHP vial, removed the cap, added a small amount of KHP to the Erlenmeyer flask, reweighed the vial, and recapped it. She performed the technique.
False
Exp 16.2: Ensuring the pH probe is immersed in the water solution and is charging is the appropriate way to store pH probes
False
This footwear is appropriate for lab
False
This is appropriate for lab
False
This is appropriate for lab. (Assuming proper PPE will be worn)
False
When discussing intermolecular forces, electronegativies of atoms in molecules are not important
False
The equilibrium below is the reaction of interest. In the preparation of the standard solutions, which reactant will be used in excess? Which reactant will essentially be converted entirely to product? Fe 3+ + SCN- ---> [Fe(NCS)] 2+
Fe(NO3)3; NaSCN
Accuracy
Obtaining the values that are closest to the actual or true value
random uncertainty
Occurs when there are errors that are not within the experiment
The same sample of dried potassium hydrogen phthalate (KHP) was measured on a tared (zeroed) analytical balance three times. the masses displayed were 0.255-, 0.261-, and 0.254-g
Random Uncertainty
A 10-mL burette consistently delivers 2.91 +/- 0.02 mL when drained from 0.01 mL to 2.01 mL and consistently delivers 1.94 +/- 0.03 mL
Systematic Uncertainty
A 25-mL transfer pipette consistently delivers 24.984 +/- 0.007 mL
Systematic Uncertainty
Precision
The ability to obtain values that are close to each other several times throughout the experiment
Acids may have several equivalence points due to the presence of multiple protons
True
Double gloving can provide additional protection against hazardous chemicals
True
Everyone should be wearing PPE in the lab
True
Exp 12: There should NOT be any liquid waste in this lab
True
Exp 15.1: Micropipettes will be used in this lab. This instrument allows for more accurate volume acquisition than a graduated cylinder
True
Exp 15.1: Molar absorptivity coefficients are dependent upon every specific reaction
True
If ankle is exposed, socks should be worn to cover the bare skin
True
It is important to know the location of the safety equipment
True
This is appropriate clothing attire for lab
True
This is appropriate for lab. (Assuming proper PPE will be worn)
True
This mesh shoe (contains holes) is appropriate for lab
True
After disposing of a material into a hazardous waste container, always ____________
close the lid