Unit 7 - The Mole Test Review

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What is the mole in chemistry?

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The mole is a unit of measurement used to express amounts of a chemical 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.

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What is molar mass?

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Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in a molecule.

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How do you calculate the percent composition of a compound?

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

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What is an empirical formula?

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

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What is a molecular formula?

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

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

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To find the empirical formula, divide the subscripts in the molecular formula by their greatest common divisor.

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What is the difference between empirical and molecular formulas?

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The empirical formula shows the simplest ratio of elements, while the molecular formula shows the actual number of atoms in a molecule.

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What is the significance of Avogadro's number (6.02 x 10^23)?

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Avogadro's number is the number of atoms, molecules, or particles in one mole of a substance.

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What is the molar mass of water (H₂O)?

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The molar mass of water is approximately 18.02 g/mol (2 hydrogen atoms at 1.01 g/mol each and 1 oxygen atom at 16.00 g/mol).

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How do you convert grams to moles?

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To convert grams to moles, divide the mass of the substance by its molar mass.