A atom has 20 electrons, 21 neutrons, and 20 protons. What is the atomic mass of the atom?

Aluminum–lithium (al-li) alloys have been developed by the aircraft industry to reduce the weight and improve the performance of its aircraft. a commercial aircraft skin material having a density of 2.47 g/cm3 is desired. compute the concentration of li (in wt%) that is required.

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

Which of the following is most likely true about water in chemical solutions?