Atomic Mass/Percent Composition. Average of Isotopes Every element typically exists in several isotope forms Isotopes are atoms of the same element with.

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Average Atomic Mass & % Abundance

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Presentation transcript:

Atomic Mass/Percent Composition

Average of Isotopes Every element typically exists in several isotope forms Isotopes are atoms of the same element with different numbers of neutrons The mass recorded on the periodic table is a weighted average of all the naturally occurring isotopes of the element

Mass Spectometer Instrument used to measure the mass of components of a substance

Example Chlorine is found in two isotope forms. One has a mass of amu, the other a mass of amu. The first makes up 75.5% of the sample. What is the average atomic mass of the chlorine?

Percent Composition In a compound, each element has constant percent of each element by mass (law of definite composition) What is the percent composition of each element in the compound C 10 H 14 O?

Example What is the mass of carbon in 2.86g of CO 2 ? What is the mass of hydrogen in 1.85g of water?