Extension of the elbow is an example of which of the following?

Choose the correct statement about muscle contraction

Which of the following systems communicates with instructions form the CNS (central nervous system) with signals responsible for controlling our visceral organs (i.e. heart, glands, piloerector muscle, etc.); causing involuntary, subconscious actions.

(WCSP24) In the spectroscope experiment, you studied the interaction of visible light with matter.  Select the type of particles involved in transitions when visible light interacts with matter.

Read the volume measured in the graduated cylinder below.  Report the value with the appropriate number of significant figures and an uncertainty. (WCSP24) [blank1]

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) You used a titration in the water hardness experiment.  Please respond to the following in a few words: a.  Why is a titration useful? b.  Describe what is happening at the atomic level throughout the titration. c.  How do we know that the titration is complete?

(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

Edit the abstract below by selecting the sentences that should be removed in the final draft. (WCSP24) Single replacement reactions occur when a single element reacts and takes the place of another element in a compound. I learned about stoichiometry when I did this experiment.  Herein, the synthesis of copper from aluminum and copper(II) sulfate is described. 5.0 g of aluminum were added to 50 mL of copper(II) sulfate.  Once the chemical reaction was balanced, I was able to determine the amount of moles of each reactant used when undergoing the reaction to produce copper. The mass of copper isolated was 1.5 g giving a yield of 86%. This lab was super fun!  

(WCSP24) Predict whether each of the molecules below is polar or nonpolar.  a) Cl-Cl   [drop1] b)   [drop2] c)  [drop3]