How do you test the purity of a substance?

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

Which of the following is a conclusion that resulted from ernest rutherford’s scattering experiment? (will mark brainliest) a. the nucleus is negatively charged b. the atom is a dense solid and is indivisible c. the mass is conserved when atoms react chemically d. the nucleus is very small and the atom is mostly empty space

Anitrogen atom and an oxygen atom combine chemically to form nitric oxide. what is nitric oxide?