What is the universe made of? Astronomers face an embarrassing conundrum: they don't know what 95% of the universe is made of.

What does a particular point on a line of a phase diagram represent? o a. the maximum temperature a substance can exist at without bonds breaking b. the pressure created by the kinetic energy of molecules at a particular temperature c. the melting point or boiling point of a substance at a specific pressure d. the conditions in which temperature and pressure have equal effects on a substance

What is the molarity of 60.0 grams of naoh dissolved in 750 milliliters of water? a) 1.1 m b) 2.0 m c) 12 m d) 75 m

How many absorptions would you expect to observe in the 13c nmr spectra of the following molecules? a) 3-chloropentane b) cis-4-methyl-2-pentene