What do we beileve is at the center of the milky way

A) two stars that have collided together
B) a cluster of stars
C) A black hole
D) A collapsed planet

Which statement best describes the oxidation numbers of the atoms found in magnesium chloride? a. magnesium has a 2- oxidation number and chlorine has a 1+ oxidation number. b. magnesium has a 2- oxidation number and chlorine has a 2+ oxidation number. c. magnesium has a 2+ oxidation number and chlorine has a 1- oxidation number. d. magnesium has a 1+ oxidation number and chlorine has a 1- oxidation number.

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

Asolution of sodium hydroxide was titrated against a solution of sulfuric acid. how many moles of sodium hydroxide would react with 1 mole of sulfuric acid?