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18.  (WCSP[x], 6 points) A student experimentally observed three (3) emission lines from a hydrogen tube in her spectroscope. One of these was a red line that was determined to have a wavelength of 664 nm. She thinks that this is due to an electron undergoing a transition from the third to the second orbit. a.  Assume that the Bohr model is correct and calculate the wavelength predicted for the n=3 to n=2 transition.  (Equations and constants are listed above.)   Enter the value in the box below.   

(WCSP24) Using the data below, answer the following questions by entering a single letter (a-e) in the box: a.  Which measurement is the most precise?  [blank1] b.  Which measurement has the fewest significant figures? [blank2]   Measurement ± Uncertainty (mL) a 10.5 ± 0.5 b 10. ± 1 c 1.00 ± 0.02 d 500 ± 100 e 250.0 ± 0.1

7.  A chromatography experiment was used to determine components in a mixture. a.  Calculate the Rf values for spot A and spot B using your ruler. Show your work. Use appropriate significant figures in your measurements and calculations.  (6 points, WCSP24.[x])    b. The stationary phase for the previous chromatogram was cellulose, which is highly polar due to the presence of multiple hydroxyl (OH) groups.  The mobile phase was water.  Given this, identify which amino acid (a building block for proteins) shown below corresponds to A and B.  Explain your reasoning. (6 points)   Enter the Rf value of spot A in the box below.

11.  A student is determining the Ideal Gas Law constant with the reaction of calcium carbonate and vinegar as shown below. Rather than using different moles of reactants and measuring volume of gas produced, the student decided to use different temperatures and measure the volume. (WCSP24.[x]) 2 CH3COOH (aq) +  CaCO3 (s)

(WCSP24) Predict whether or not the pairs of compounds shown below will be miscible or immiscible. a) [drop1]   b) [drop2]   c) [drop3]

(WCSP24) What is the difference between a line and continuous spectrum?  Please explain in a few words.

(WCSP24) Given the diagrams or processes below, indicate whether they are a chemical and/or physical change.   a) Water boiling   [drop1] b) Burning a candle  [drop2] c)  The process depicted in the figure below  [drop3]

How does pluralism view human differences?

What was the result of the 2002 Ninth Circuit court ruling in Newdow v. United States Congress?

What is the first step and most basic tactic when trying to promote social change?