CHM 111 Lecture Notes - Lecture 19: Mass Spectrometry, Carbon-12, Molar Mass

• School: University of Miami
• Department: Chemistry
• Course: CHM 111
• Professor: Lewis Nita

Document Summary

(cid:403) this analytical technique identifies the chemical composition of a compound or sample based. Mass spectrometry on the mass-to-charge ratio of ions, using a mass spectrometer. The mass spectrometer causes a sample to first undergo chemical fragmentation and form ions which are then passed through electrical and magnetic fields to determine the ratio of charge to mass of the particles. The sta(cid:374)da(cid:396)d of (cid:373)ass i(cid:374) (cid:272)he(cid:373)ist(cid:396)(cid:455), (cid:271)(cid:455) (cid:449)hi(cid:272)h e(cid:448)e(cid:396)(cid:455) othe(cid:396) ele(cid:373)e(cid:374)t has it"s mass established relative to, is the carbon atom. Specifically, the carbon atom with 6 protons and 6 neutron, carbon-(cid:1005)(cid:1006), defi(cid:374)ed to ha(cid:448)e a (cid:373)ass of e(cid:454)a(cid:272)tl(cid:455) (cid:1005)(cid:1006) ato(cid:373)i(cid:272) (cid:373)ass u(cid:374)its (cid:894)a(cid:373)u"s(cid:895). As a (cid:396)esult, a(cid:373)u"s do (cid:374)ot ha(cid:448)e a(cid:374)(cid:455) u(cid:374)its. The standard of mass is the carbon atom (isotope) that has 6 protons and 6 neutrons in its nucleus. With atoms, quadrillions of which may be in a speck of dust, we need a much larger number for this pu(cid:396)pose.