Moles Flashcard - APA

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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.

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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 percent composition?

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Percent composition is calculated by dividing the mass of each element in a compound by the total molar 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 is 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 convert atoms to grams?

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To convert atoms to grams, first convert atoms to moles using Avogadro's number (6.022 x 10^23 atoms/mole), then multiply by the molar mass of the substance.

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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 particles in one mole of a substance.

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How do you find the mass of a sample from the number of atoms?

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To find the mass of a sample from the number of atoms, use the formula: mass = (number of atoms / Avogadro's number) x molar mass.

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What is the percent composition of hydrogen in water (H2O)?

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The percent composition of hydrogen in water is approximately 11.2%.

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How do you determine if two compounds have the same empirical formula?

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Two compounds have the same empirical formula if they can be reduced to the same simplest ratio of elements.