Molecules and Moles

Molecules and Moles - of an ionic compound is calculated by...

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Molecules and Moles A molecule is a combination of two or more atoms that are held together by  covalent bonds . A molecule is the smallest unit of a compound that still displays  the properties associated with that compound. Molecules may contain two atoms  of the same element, such as O2 and H2, or they may consist of two or more  different atoms, such as CCl4 and H2O. In the study of chemistry, molecules are  usually discussed in terms of their molecular weights and moles. Ionic   compounds, such as NaCl and KBr, do not form true molecules. In their  solid state, these substances form a three-dimensional array of charged particles.  In such a case, molecular weight has no meaning, so the term  formula weight  is  used instead. Molecular Weight and Formula Weight The molecular weight of a molecule is calculated by adding the  atomic weights   (in atomic mass units or amu) of the atoms in the molecule. The formula weight 
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Unformatted text preview: of an ionic compound is calculated by adding its atomic weights according to its empirical formula. The Mole A mole is defined as the quantity of a substance that has the same number of particles as are found in 12.000 grams of carbon-12. This number, Avogadro's number, is 6.022x1023. The mass in grams of one mole of a compound is equal to the molecular weight of the compound in atomic mass units. One mole of a compound contains 6.022x1023 molecules of the compound. The mass of 1 mole of a compound is called its molar weight or molar mass . The units for molar weight or molar mass are grams per mole. Here is the formula for determining the number of moles of a sample: mol = weight of sample (g) / molar weight (g/mol)...
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This note was uploaded on 11/18/2011 for the course CHEM ch 101 taught by Professor - during the Fall '10 term at Montgomery.

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Molecules and Moles - of an ionic compound is calculated by...

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