Which of the following is the best definition of a physical change? A. Something that can be observed or measured while changing the identity of the substance.

B. A nail rusting.

C. A change that occurs without changing the identity of the substance.

D. Ice melting into water.

For the following dehydrohalogenation (e2) reaction, draw the zaitsev product(s) resulting from elimination involving c3–c4 (i.e., the carbon atoms depicted with stereobonds). show the product stereochemistry clearly. if there is more than one organic product, both products may be drawn in the same box. ignore elimination involving c3 or c4 and any carbon atom other than c4 or c3.

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

The blackbody curve for a star name zeta is shown below. what is the peak wavelength for this star ?