Why quantum mechanics is only relevant to small objects

Achemistry student needs of 40ml diethylamine for an experiment. by consulting the crc handbook of chemistry and physics, the student discovers that the density of diethylamine is 0.7 . calculate the mass of diethylamine the student should weigh out. round your answer to significant digits.

Which feature indicates that mars resides in the inner region of the solar system

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?