DESN 120A Study Guide - Quiz Guide: Color Constancy, Primary Color, Secondary Color

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maudelee

22 Dec 2022

School

CSULB

Department

Design

Course

DESN 120A

Professor

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Document Summary

Review these lectures/handouts (available on beachboard): value, color theory, color in context. A color mixing system in which combinations of di erent wavelengths of light create visual sensations of color. A psychological compensation for changes in light when observing a color. A viewer interprets the color to be the same under various light conditions. Any one of a number of color relationships based on groupings within the color wheel [examples: analogous color (adjacent color), color triad (three colors equidistant), complementary (opposite)]. A color closer to blue on the color wheel. A network of horizontal and vertical intersecting lines that divide spaces and create a framework of areas. A property of color deined by distinctions within the visual spectrum or color wheel. Red, blue, yellow and green are examples of hue names. A color scheme using only one hue with varying degrees of value or intensity. The three colors from which all other color theoretically can be mixed.

Related Questions

Data Analysis for Part A. Use your table of wavelength and colorobserved to answer the follwoing:

1. Over what wavelength rage do you observe Red? Yellow? BlueSummarize these ranges below your table.

Data Anaylsis for Part B.By referring to your table, answer thequestions below:

3a. Examine a set of solutions having the same concentration.Does the wavelength absorbed max change with the anion, the cationor both? what do you conclude is causing the absorbance?

3b. Examine pairs of solutions having the same compound butdifferent amounts of compound in the solution(differentconcentrations). Does the absorbance intensity change withconcentration? Write a sentencesating this and suggest areason.

4.Now consider the relationship between the color of thesolution and the wavelength, (plus and minus 5nm) max, assoicatedwith the greatest absorbance by nswering the followingquestions:

a. by referring to part A, write down the color thatcorrresponds to the wavelength max of the cobalt solution. Comparethis color with the observed color of the cobalt solution. Arethese colors the same or different? Write a sentence summarizingthis and suggest an explanation.( You may find it helpful to reviewthe concept o the colors of light transmitted vs the colors oflight absorbed, which is easily visulaized by drawing out theprimary color wheel).

b. Repeat this analysis for the nickel solutions and write asentence summarizing your findings and suggest anexplanation.

Data Anaylsis for Part C.

5.why do sodium chloride and sodium nitrate produce the samecolor flame?

6.Report they identity of your unknown and your evidence forthis determination.

7.Consider the identity the emission spectra of the cobalt andnickel salts. Write down the approximate wavelength correspondingto the observed colors. Compare these values with those youobtained in Part B.4. Are they the same or different? Can youexplain your observation?

Part A: The relationshiop between color and wavelength Part C. CompoundIon flamecolor

Nm Color LithiumChloride hotpink

700 red CopperIIchloride lightblue

680 redorange Unknown#1 purpleorange

660 orange SodiumNitrate Orange

640 orange StrontiumNItrate Orange-red

620 orangeyellow NickelChloride brightorange

600 lightorange potassiumsulfate orange

580 yellow sodiumchloride brightorange

560 yellow cesiumchloride pinkishorange

540 yellow bariumNItrate lightgreen

520 yellowgreen calciumnitrate red-orange

500 green

480 dark blue

460 oceanblue

440 dark blue

420 oceanblue

400 purpleblue

Part B.Solution Molaritymax Colorofsolution Wavelengthmaxnm AbsorbanceIntensity (nm)

CoSo4 x7H20 0.05M lightpink 517.80 .262

0.10M darkpink 512.20 .394

CoCIn x6H20 0.05M lightpink 515.30 .232

0.10M pink 511.20 .809

Ni(NO3)2 x 6H20 .05M seafoamgreen 396 .268

.10M seafoamgreen 396 .528

NiSo4 x6H20 .05M lightseagreen 389 0.282
.10M seagreen 395 0.501

CHEM 114 â Lab Experiment 7 Equilibrium I â Determination of an Equilibrium Constant

3. In this lab, the measurement wavelength on the colorimeter was set at 470 nm. This measurement wavelength was the best choice available on the colorimeter but it was not the best chemical choice for measuring the absorbance of FeSCN2+.

a. In terms of instrument sensitivity, explain why the choice of wavelength on the colorimeter is important.

b. Since the wavelength setting was not the ideal wavelength (ï¬max) for these absorbance measurements, do you expect the value for your absorbance readings taken by the colorimeter to be too high, too low, or accurate? Explain.

c. What experiment could you do, what data would you collect, and how would you analyze the data to determine the best setting for measuring the absorbance of FeSCN2+? Be sure to fully explain how your experiment and the resulting data would allow you to determine the wavelength of maximum absorbance for the FeSCN2+ complex.

Procedure for Part 1 1.Using the TV Specs, observe and record atomic emission spectra from H lamp. 2.Sketch the atomic emission spectrum of H. Include color and wavelength.3.Repeat step 1 with the Hg lamp.4.Sketch the atomic emission spectrum of Hg. Include color and wavelength.5.Repeat step 1 with the Helamp.6.Sketch the atomic emission spectrum of He. Include color and wavelength.

Procedure for Part 2

4.Conduct a full spectrum analysis of a colored solution.a.Fill a cuvette Â¾ full with the colored solution and place it in the spectrometer. Align the cuvette so that the clear sides are facing the light source of the spectrometer.b.Click . A full spectrum graph of the colored solution will be displayed.c.Once signal has stabilized, click d.Examine the graph, noting the peak or peaks of very high absorbance or other distinguishing features. Compare the color of the solution with the wavelength associated with that color. Use the ârainbowâ chart drawn above.e.To Save your graph, select Store Latest Run from the Experiment menu.

Post lab question

1. Briefly explain why the gas discharge tube glows when the high voltage is

applied. Why does the gas not glow when the voltage is turned off.

2. When you look directly at the gas discharge tube through the grating, do you see the color

of a single wavelength of light or a blend of wavelengths?

3.Other than our blending of colors of different wavelengths emitted from a single source,

what is another limitation of using our eyes to detect electromagnetic radiation?

4. Explain how the emission phenomenon can be used

to find out what elements are present in an unknown sample.

5. What is a continuous spectra? What type of source creates a continuous spectra?

6. Explain why atomic emission spectra are not continuous.

7. How many lines are there in the Hg line spectra? How many

did you see? What might be the reason that these two answers are different?

8. Why do atoms absorb and emit light of the same frequency? In other words, why donât

atoms absorb light at one set of frequencies and emit light at another set of frequencies?

9. Why does the atomic emission spectrum vary from element to element? Explain how

atomic structure influences the spectrum.

10. In part 2, does the wavelength of maximum absorbance (ie: the color that corresponds to

the wavelength) for each solution correspond to the color of the solution that you âseeâ?

Describe why or why not? (For instance, for the red solution, was the highest absorbance

measured at the red wavelength and describe why or why not?)

plz help me answer as much as possible thanks

DESN 120A Study Guide - Quiz Guide: Color Constancy, Primary Color, Secondary Color

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