CHEM 1070 Lecture Notes - Lecture 6: Nucleon, Atomic Mass, Molar Mass

• School: University of Iowa
• Department: Chemistry
• Course: CHEM 1070
• Professor: Alexeeva Natalia

Document Summary

One mole of anything is 6. 022 10^23 units of that thing. Atomic mass is the average mass of all atoms of an element. Molar mass is the mass of 1 mole of atoms of an element. 1 amu = mass of 1 nuclear particle. Compound - material formed of two or more elements in definite proportions. Compounds can be decomposed to elements and/or simpler compounds. Chemical formula gives the whole-number ratio of moles of element in the compound. To calculate percentage we divide the part (mass of element) by the whole (mass of compound) Mass percent composition or mass percent of an element is the element"s percentage of the total mass of the compound. Empirical formula is the simplest whole-number ratio. Laboratory analysis often provide masses of each element in a compound, not chemical formulas. Knowing the ratios between masses of elements we can obtain empirical formula for a compound.