CHEM 1A Chapter Notes - Chapter 3: Mass Spectrometry, Molar Mass, Chemical Formula

• School: UCSB
• Department: Chemistry and Biochemistry
• Course: CHEM 1A
• Professor: Joseph C A

Document Summary

Chemical stoichiometry- quantities of materials consumed and produced in chemical reactions. (cid:862)ato(cid:373)i(cid:272) masses(cid:863: modern system of atomic masses, instituted in 1961, is based on. These electrons turn atoms/molecules being analyzed into + ions. Electric field deflates paths of ions (amount of deflection depends on mass)- ions separate. A comparison of the positions where the ions hit the detector plate gives very accurate mass values. Mass of 13c = (1. 0836129)(12 amu)= 13. 003355 amu: sometimes atomic mass referenced as atomic weight, atomic masses are generally reported as average values of the isotopes of that element, look i(cid:374) (cid:374)otes/ (cid:271)ook fo(cid:396) e(cid:454)a(cid:373)ples . (cid:862)the mole(cid:863: mole- the number equal to the number of carbon atoms in exactly 12 grams of pure 12c, avogad(cid:396)o"s (cid:374)u(cid:373)(cid:271)e(cid:396)- one mole of something consists of 6. 022 x. 10^23 units of that substance: ee (cid:374)otes/(cid:271)ook fo(cid:396) e(cid:454)a(cid:373)ples . (cid:862)mola(cid:396) mass(cid:863: the mass of 1 mol of methane can be found by summing the masses of carbon and hydrogen present: