CHEM 130 Chapter Notes - Chapter 5: Balance Equation, Reagent, Molar Mass

• School: U of M
• Department: Chemistry
• Course: CHEM 130
• Professor: Jadwiga Sipowska

Document Summary

Determine the number of atoms in a sample by finding the mass. Mass spectrometer is the most accurate method currently available for comparing masses of atoms. Amount of path deflection depends on the mass of the ion; more massive ions have a smaller deflection. Used to determine the isotopic composition of a natural elements; peaks indicate relative abundances. Atomic mass is an average value reflecting the average of the isotopes composing it. Mole (mol) is the number equal to the number of carbon atoms exactly in 12 grams of pure 12c. Avogadro"s number defines the mole as 6. 022x1023 of something; 1 mole carbon = 6. 022x1023 atoms. Mole is defined such that a sample of natural element with a mass equal to the elements atomic mass expressed in grams as one mole of atoms. Molar mass of a substance is the mass in grams of one mole of the compound (molecular weight) Obtained by summing the massed of the component atoms.