Chem Lab Final

How long should the methods section of your post-lab report be? As long as the provided protocol. 3-5 sentences. Four paragraphs. There should not be a methods section.

3-5 Sentences

What does CaCO3 look like? (Hint: We've worked with this compound in previous labs.) A Yellow Solid A Yellow Liquid A Clear Liquid A White Solid

A white Solid

Which of the following is another name for vitamin C? Ascorbic Acid Acetic Acid Amino Acid Salicylic Acid

Ascorbic Acid

Which of the following is iodate? I3- I2 I- IO3-

IO3-

Which dilution approach involves using each solution you make as a stock solution that is diluted to produce the next solution? Trademark Serial Parallel Isotopic

Serial

Consider the reaction occurring in today's experiment. What is the limiting reagent if one mole of CaCl2 is mixed with half a mole of Na2CO3? Sodium Carbonate Calcium Chloride Sodium Chloride Calcium Carbonate

Sodium Carbonate

Decanting can separate ________ from ________. liquids, liquids solids, liquids solids, gases liquids, gases

Solids, liquids

What instrument will you use to measure the emission spectrum for the different sources of light? Spectrophotoscope Spectroscope Spectrophotometer Spectrometer

Spectroscope

How much 6 M NaOH would you need to make 300 mL of a 2 M NaOH solution? 100 mL 900 mL 200 mL 700 mL

100 mL

Imagine you completed this lab as described. If the final mass of your mixture was found to be 4.35g but you expected a mass of 3.84g, what is your percent error? 11.7% 0.117% 0.883% 88.3%

11.7%

In Beer's Law, what does A stand for? Activity Absorbancy Absorption Absorbance

Absorbance

If a measurement closely matches a known value, then the measurement is ________. Precise Neither Accurate nor Precise Accurate Both Accurate and Precise

Accurate

What is a precipitate? An aqueous solution An insoluble solid A reactant An dense liquid

An insoluble solid

Why should there be a data point on a calibration curve at the point (0, 0)? Because nothing absorbs light at zero concentration. Because you start at time 0. Because all plots go through the point (0, 0). Because you calibrate the colorimeter using a blank.

Because you calibrate the colorimeter using a blank.

Which chemical in the mixtures is limestone? Silicon Dioxide None of the components of the mixture make up limestone. Calcium Carbonate Potassium Chloride

Calcium Carbonate

Your protocol asks you to take ONLY the amount of cobalt ion stock solution that you need and no more. Why? Cobalt solutions are expensive. Cobalt solutions take weeks to prepare. Cobalt solutions can stain your clothes. Cobalt solutions are dangerous.

Cobalt solutions are expensive

A beaker is designed to deliver accurate volumes of liquid. True False

False

The methods section of your lab notebook should be copied word for word from the protocol. True False

False

When writing a methods section, you must be sure to tell your audience (i.e. those reading your report) which buttons to push on the instruments used in your experiments. True False

False

What should you do if you get HCl on your skin (say, on your arm)? Stop, drop, and roll. Neutralize it with strong base. Flush it with water. Wipe it off with a paper towel.

Flush it with water

What does it mean for an electron to be excited? It is at a higher energy level. It interacts with another electron. Its angular momentum has been kept constant. It wants to PARTY!

It is at a higher energy level

Which of these chemicals has historically been used to make soap? Sodium Lye Bleach Sucrose

Lye

What does the symbol 𝑥̅ represent? Variance Deviation Standard Deviation Mean

Mean

You have recorded a table of data in your lab notebook that you used to construct a calibration curve. Should you include both a data table and a figure of your calibration curve in your lab report? You should include neither your table nor your plot. It depends on your TA. No Yes

No

Patty and Tran are lab partners, and together they construct two calibration curves. Patty's curve has an R2 of 0.998, while Tran's has an R2 of 0.757. Whose calibration curve is better? Patty's It's impossible to tell. Tran's Both are equally as good.

Patty's

Filtration separates chemicals based on differences in their ________ properties. Neither Chemical nor Physical Physical Chemical and Physical Chemical

Physical

What is h in the Equation 1? Planck's constant. The wavelength of light. The mass of an electron. The speed of light.

Planck's Constant

Balmer identified a way to mathematically describe hydrogen's spectral lines, but this was in conflict to Rutherford's model of the atom. What feature of Balmer's model did Rutherford ignore? electron configurations protons and neutrons being in the nucleus quantum numbers orbitals

Quantum Numbers

Why are free radicals bad for our health? They take up space that could be used for nutrients. They are highly chemically reactive. They cannot interact with other molecules. They diffuse freely throughout your body.

They are highly Chemically reactive

When should you update you lab notebook's table of contents? Only when your notebook is graded. Throughout the semester. No table of contents is needed. Only at the end of the semester.

Throughout the semester.

How do you dispose of the used filter papers at the end of this lab? Put them in hazardous waste containers. Dry them off and recycle them next week. Take them home with you to keep. Throw them away in the trash can.

Throw them away in the trash can.

When used properly, TD glassware will still have a small amount of liquid coating the sides. True or False

True

You are graded on how accurately you can determine the composition of your unknown sample. True False

True

What setting on the colorimeter do you adjust to get a calibration curve with the greatest slope? Concentration Absorptivity Wavelength Absorbance

Wavelength

If absorbance is directly proportional to concentration, which of the following is true? When concentration increases, absorbance increases. When concentration increases, absorbance decreases. There is no connection between concentration and absorbance. When concentration decreases, absorbance increases.

When concentration increases, absorbance increases.