In addition to identifying a chemical's composition, what can often be determined using gas chromatography, mass spectroscopy or infrared spectrophotometry or a combination of these tests?
a) retailer
b) manufacturer
c) storage location
d) arsonist's identity

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8