Which best describes a compound such as sodium chloride?

a pure substance that can be separated into different elements by physical means
a mixture of two common substances that can be separated by chemical means
a mixture of two common elements that can be separated by physical means
a pure substance that can be separated into different elements by chemical means

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.

Consider the directing effects of the substituents on salicylamide and predict the possible structures of the iodination products. which do you think will be the major product?

Helium decays to form lithium. which equation correctly describes this decay?