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.