Moles Review

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What is a mole in chemistry?

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A mole is a unit of measurement used to express the amount of a substance. It is defined as the amount of substance that contains as many entities (atoms, molecules, etc.) as there are in 12 grams of carbon-12.

Front

How do you calculate the number of formula units in a given mass of a compound?

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To calculate the number of formula units, divide the mass of the compound by its molar mass to find the number of moles, then multiply by Avogadro's number (6.022 x 10^23).

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What is the empirical formula?

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The empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

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How do you determine the molecular formula from the empirical formula?

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To find the molecular formula, divide the molar mass of the compound by the molar mass of the empirical formula, then multiply the subscripts in the empirical formula by this ratio.

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What is percent composition?

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Percent composition is the percentage by mass of each element in a compound, calculated by dividing the mass of the element by the total mass of the compound and multiplying by 100.

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How do you calculate the percent mass of an element in a compound?

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Percent mass = (mass of element in the compound / total mass of the compound) x 100.

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What is Avogadro's number?

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Avogadro's number is 6.022 x 10^23, which is the number of atoms, molecules, or formula units in one mole of a substance.

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What is the molar mass of NaCl?

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The molar mass of NaCl (sodium chloride) is approximately 58.44 g/mol.

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How do you convert moles to grams?

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To convert moles to grams, multiply the number of moles by the molar mass of the substance.

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What is the significance of the molecular formula?

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The molecular formula shows the actual number of atoms of each element in a molecule of the compound.