CHEM 1101: Skills Check #2

The most precise glassware on the list to measure a small volume.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: 10 mL Graduated Pipet

Explanation:

The following are disposal locations, not measuring tools.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

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• 50 mL Beaker

• Not precise, volume markings are a rough estimate.

• 50 mL Graduated Cylinder

• Measures volume, but it’s meant for larger amounts. The scale spacing makes small volumes less precise.

• 10 mL Graduated Pipet

• Designed specifically to measure and transfer small volumes accurately, with fine graduations.

• 10 mL Graduated Cylinder

• Better than a 50 mL cylinder for small volumes, but still not as precise as a pipet.

• 50 mL Volumetric Flask

• Very precise for making one solution to exactly 50.0 mL, not for measuring different small volumes.

Where you dispose of extra unreacted Zn from the copper cycle experiment.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Solid Chemical Waste

Explanation:

Unreacted Zn = Leftover solid zinc metal from the copper cycle

• Glass Waste

  • It’s not glass.

• Solid Chemical Waste

  • The unreacted zinc is a solid chemical.

• Liquid Chemical Waste

  • It’s a solid metal, not a liquid.

• Trash Can

  • Lab metals and chemicals never go in the trash or down the sink unless your manual says so. The copper cycle manual also says waste goes in proper containers, never the drain.

• Sink

  • “Only water down the drain. All other chemicals and materials should be disposed of properly. When in doubt, ask.”

Where you dispose of extra water that you didn't need for your parallel dilutions.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Sink

Explanation:

• This refers to the clean water you measured out to do your parallel dilutions. It hasn’t been mixed with dye or any other chemical yet.

• Lab glassware options aren’t disposal locations.

• Glass Waste

• This is for broken glass.

• Solid Chemical Waste

• This is for solid chemicals or contaminated solids.

• Liquid Chemical Waste

• Since it’s just unused water, it’s not contaminated and not hazardous.

• Trash Can

• This is for regular dry trash, not liquids.

• Sink

• Clean, unused water is safe to pour down the drain.

Where you dispose of your aspirin sample that remains after you have used part of it to analyze.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Solid Chemical Waste

Explanation:

• After you analyze part of your aspirin, the rest is still a chemical sample. It’s a solid organic compound, even if it seems harmless

• Glass Waste

• This is only for broken or disposable glass, not chemical solids.

• Solid Chemical Waste

• This is for solid chemicals or contaminated solids.

• Liquid Chemical Waste

• The remaining aspirin sample isn’t a liquid.

• Trash Can

• This is for regular dry trash, not liquids.

• Sink

• Lab-made chemicals never go in the trash can.

Where you dispose of extra hydrochloric acid left over after an experiment.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Liquid Chemical Waste

Explanation:

• Glass Waste

• This is only for broken or disposable glass.

• Solid Chemical Waste

• This is for solid chemicals or contaminated solids.

• Liquid Chemical Waste

• Extra hydrochloric acid is a liquid acid reagent left after the experiment.

• Trash Can

• This is for regular non-chemical trash.

• Sink

• “Only water down the drain. All other chemicals and materials should be disposed of properly. When in doubt, ask.”

Where you dispose of chemicals that you scrape off of your filter paper.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Solid Chemical Waste

Explanation:

• Glass Waste

• This is only for broken or disposable glass.

• Solid Chemical Waste

• Chemicals scraped off filter paper are solid residues.

• Liquid Chemical Waste

• Extra hydrochloric acid is a liquid acid reagent left after the experiment.

• Trash Can

• This is for regular non-chemical trash.

• Sink

• “Only water down the drain. All other chemicals and materials should be disposed of properly. When in doubt, ask.”

Where you dispose of a test tube that broke in the centrifuge.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Glass Waste

Explanation:

• The main issue is broken glass.

• In lab safety, any broken glassware goes in the glass waste or broken glass container. This is to protect custodial staff and prevent puncture injuries.

• The prompt doesn’t say the test tube had hazardous chemicals in it; it just says it broke in the centrifuge. So we follow the standard broken glass rule.

Where you dispose of the supernantent that you decanted in the copper cycle lab

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: Liquid Chemical Waste

Explanation:

• In the copper cycle, the supernatant you decant after heating with sodium hydroxide (NaOH) is the leftover liquid sitting above the solid.

Lab Manual: NOTE: The supernatant is mostly basic, so we are keeping it separate from the rest of the waste. Please place the waste from this step in the container with a label that includes “sodium hydroxide 10%”

• That labeled container is a liquid waste container, just a specific one for basic sodium hydroxide (NaOH) containing liquid.

You should pour from a stock bottle in the hood into this glassware.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: 50 mL Beaker

Explanation:

• Stock Bottle = The big shared reagent bottle that stays in the fume hood. You don’t take it to your bench, and you try to minimize contamination.

• When you pour out of a stock bottle, you want something:

  • Wide-mouthed, so you don’t miss and spill.

  • Easy to rinse if a little extra goes in.

  • Not used for precise measuring yet.

That points to a simple beaker.

• Graduated cylinders and pipets are for measuring after you have a smaller working amount. You shouldn’t pour directly into them from a stock bottle because it’s easy to overshoot and contaminate the stock bottle’s rim.

• Volumetric flasks are for making solutions to an exact volume. You usually add reagent using a smaller container or pipet, not by pouring straight from the stock bottle.

The piece of glassware that would be the best choice to make a 50.0 mL solution

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: 50 mL Volumetric Flask

Explanation:

• You need to prepare a solution with an exact final volume of 50.0 mL.

• 50 mL Beaker

• Not precise, volume markings are a rough estimate.

• Graduated Cylinders

• Decent for measuring, but not as accurate as a volumetric flask for making a solution to an exact final volume.

• 10 mL Graduated Pipet

• Used to transfer small measured amounts, not to set a final total volume.

• 50 mL Volumetric Flask

• Calibrated to contain one precise volume (50.0 mL) when filled to the line. 

The best choice of glassware to use when measuring solutions for parallel dilutions.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: 10 mL Graduated Pipet

Explanation:

• Parallel Dilutions = Making several diluted solutions side by side, usually for something like a standard curve. The key is that each dilution needs accurate, repeatable volumes.

• For dilutions, small differences in volume change the concentration a lot. So you want the tool that gives the most precise measurement of liquid volume.

The best choice of glassware to measure the volume of NaOH that you added to your solution in the copper cycle.

• Glass Waste

• Solid Chemical Waste

• Liquid Chemical Waste

• Trash Can

• Sink

• 50 mL Beaker

• 50 mL Graduated Cylinder

• 10 mL Graduated Pipet

• 10 mL Graduated Cylinder

• 50 mL Volumetric Flask

Answer: 10 mL Graduated Cylinder

Explanation:

• Add approximately 5 mL of Sodium hydroxide (NaOH) 

• All volumes were “approximately” measured, not “precisely” measured.

For this molecule, select all statements below that apply:

• Forms no hydrogen bonds

• Forms hydrogen bonds with itself.

• Forms hydrogen bonds with water.

Answer: Forms no hydrogen bonds

Explanation:

• Hydrogen bonding needs:

  • Hydrogen bond donor: H atom attached to a N, O, or F.

  • Hydrogen Bond Acceptor: Often another N, O, or F.

Check if this molecule has donors.

• Toluene has only C and H.

• There is no O-H, N-H, or F-H bond.

• So, it can’t donate hydrogen bonds.

Check if this molecule has acceptors.

• There are no n, 

For this molecule, select all statements below that apply:

• Forms no hydrogen bonds

• Forms hydrogen bonds with itself.

• Forms hydrogen bonds with water.

Answer: Forms hydrogen bonds with water

Explanation:

• ____

For this molecule, select all statements below that apply:

• Forms no hydrogen bonds

• Forms hydrogen bonds with itself.

• Forms hydrogen bonds with water.

Answer: Forms hydrogen bonds with water

Explanation:

• ____

Why was the discovery of the first synthetic polymer revolutionary? Select all that apply.

• Humans could create new materials.

• It helped the environment.

• Material wealth became more widespread.

• Humans would need to continue to depend on natural resources.

• Human manufacturing will still be constrained by the limits of nature.

Answer(s):

• Humans could create new material.

• It helped the environment.

• Material wealth became more widespread.

Explanation:

• ____

What are the two ways that monomers can be joined to form polymers?

• Addition

• Condensation

• Substitution

• Formation

Answer(s):

• Addition

• Condensation

Explanation:

• ____

Can both types of polymers be melted and reformed (recycled)?

• Yes, both are thermoplastic and can be easily processed, reprocessed, or recycled.

• No, addition polymers are thermoplastic but condensation polymers are thermoset and cannot be melted and reformed.

• No, condensation polymers are thermoplastic but addition polymers are thermoset and cannot be melted and reformed.

Answer: No, addition polymers are thermoplastic but condensation polymers are thermoset and cannot be melted and reformed.

Explanation:

• ____

Ammonia can be synthesized by the following reaction:

2NO (g) + 5 H₂ (g) → 2NH₃ (g) + 2 H₂O (g)

If you begin with 87 grams of NO and 27.6 grams of H₂, what is the theoretical yield of NH₃? (write your answer to 1 decimal place)?

Ammonia can be synthesized by the following reaction:

2NO (g) + 5 H₂ (g) → 2NH₃ (g) + 2 H₂O (g)

If you begin with 85.6 grams of NO and 24.5 grams of H₂, what is the theoretical yield of NH₃? (write your answer to 1 decimal place)?

You perform the reaction to make ammonia. What information to you need to record in order to calculate the % yield for the reaction?

• Amount of NH₃ produced.

• Amount of water produced.

• Amount of NO remaining after the reaction.

• Amount of H₂ remaining after the reaction.

Answer: Amount of NH₃ produced.

Explanation:

• ____

What is the formula for the molecule shown below?

C:

H:

N:

O:

Answer:

• C: 16

• H: 23

• N: 1

• O: 2

Explanation:

• ____

What types of impurities could be present in a synthesis?

• Solvent

• Unreacted starting material

• Side products

• Main Products

Answer(s):

• Solvent

• Unreacted starting material

• Side products

Explanation:

• ____

The type of reaction when two soluble ions react to form an insoluble solid.

Answer: precipitation reaction

Explanation:

• ____

In the reaction Zn + H₂SO₄ → ZnSO₄ + H₂, which element, if any, is oxidized?

• zinc

• hydrogen

• oxygen

• sulfur

• none of these

Answer: zinc

Explanation:

• ____

After heating your beaker of Cu(OH)2, you formed copper (II) oxide. Before you added the H2SO4, you were instructed to decant the supernatant, add warm water, and decant again. What was the purpose of this step?

• Remove excess H₂SO₄

• Clean off the Cu(OH)₂

• Clean off the CuO

• Remove excess NaOH

Answer: Remove excess NaOH

Explanation:

• ____

What are the things to remember or use when writing a procedure?

• passive voice

• paragraph form

• past tense

• present tense

• first person

• bulleted list form

Answer(s):

• passive voice

• paragraph form

• past tense

Explanation:

• ____

2AgNO₃(aq) + CaCl₂(aq) --> 2AgCl(s) + Ca(NO₃)₂(aq)

You have a 1.00 M solution of silver nitrate and a 0.100 M solution of calcium chloride. Following the above reaction, you react 25.00 mL of each solution. What is the theoretical yield of solid? (Note: MW of AgCl = 143.32 g/mol)

Answer: 0.717

Explanation:

• ____

Error analysis would be found in which part of your report?

• Discussion

• Procedure

• Results

• Data

Answer: Discussion

Explanation:

• ____

During the aspirin synthesis experiment, you isolated the aspirin with what equipment?

• Buchner funnel

• Gravity funnel

• Separatory funnel

• Erlenmeyer flask

Answer: Buchner funnel

Explanation:

• ____

Ethanol has a lower viscosity than honey.

• True

• False

Answer: True

Explanation:

• ____

In which state of the following compounds does nitrogen have the most positive oxidation state?

• NaNO₂

• N₂O

• HNO₃

• NO₂

• NH₄Cl

Answer: HNO₃

Explanation:

• ____

Chemicals that you scrap off of your filter paper would be placed in the ___________.

• solid chemical waste

• liquid chemical waste

• trash can

• glass waste

Answer: solid chemical waste

Explanation:

• ____

The repeating part or sub-unit of a polymer.

Answer: monomer

Explanation:

• ____

In addition to avoiding spills, recapping chemical bottles and jars also prevents this (select the BEST answer).

• contamination

• evaporation

• reactions

• confusion

Answer: contamination

Explanation:

• ____

You need 50 mL of a 1.0 M NaCl solution. After you correctly measure the mass of the NaCl needed, you add the salt to 50.00 mL of water and it dissolves. Your solution is __________.

• Too dilute

• Too concentrated

• Correct

Answer: Too dilute

Explanation:

• ____

Color and appearance are examples of ___________ observations.

• qualitative

• quantative

Answer: qualitative

Explanation:

• ____

When evaluating the aspirin product, we calculated the _____ and the _____ .

Answer(s):

• percent yield

• percent purity

Explanation:

• ____

During the semester, we often separated solid chemicals from liquid chemicals. Which technique was not used?

• decanting

• diltration

• centrifugation

• evaporation

Answer: evaporation

Explanation:

• ____

When considering the strength of polymers such as nylon, stronger polymers had ________ carbon chains.

• Shorter

• Longer

Answer: Shorter

Explanation:

• ____

In the copper cycle, if we wrote reactions in the _______ form, we would show the species as ions and include the spectator ions.

Answer: ionic equation

Explanation:

• ____