Study the diagram below to the following question. which of the above images is a molecule?

This classification of drug typically changes the brain's chemistry and reduces its ability to create its own endorphins.

Sodium sulfate dissolves as follows: na2so4(s) → 2na+(aq) + so42- (aq). how many moles of na2so4 are required to make 1.0 l of solution in which the na concentration is 0.10 m?

Can someone me with 3 and 4 plz. this is for masteries test.