CHEM 130 Chapter Notes - Chapter 5: Atomic Mass, Problem Solving, Empirical Formula
Document Summary
Can be treated as if all objects had identical mass. Most accurate method currently available for comparing the masses of atoms. Atoms or molecules are passed into a beam of high-speed electrons, which knock electrons off the atoms or molecules being analyzed and change them into positive ions. Most elements occur in nature as mixtures of isotopes, thus atomic masses are usually average values. The number equal to the number of carbon atoms in exactly 12 grams of pure carbon-12. One mole of something equals 6. 022*10^23 units of that substance. The mass of one mole of an element is equal to its atomic mass in grams. The mole concept enables us to use the relative masses on the periodic table in units that can be measured. The mass in grams of one mole of the compound. The percent by mass of a component of a mixture or of a given element in a compound.
