Percent Composition

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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 composition of an element in a compound?

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To calculate percent composition, use the formula: (mass of element in 1 mole of compound / molar mass of compound) x 100.

Front

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 empirical formula from a molecular formula?

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To determine 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 of each element in a molecule.

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What is the gram-formula mass?

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The gram-formula mass is the mass of one mole of a compound, calculated by summing the atomic masses of all atoms in the formula.

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

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Percent by mass = (mass of element in 1 mole of compound / molar mass of compound) x 100.

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What is the percent by mass of fluorine in CaF2?

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The percent by mass of fluorine in CaF2 is 49%.

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How do you find the empirical formula from percent composition?

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Convert the percent composition to grams, then to moles, and divide by the smallest number of moles to find the ratio.

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What is the percent composition of Cl in HClO3?

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The percent composition of Cl in HClO3 is 42%.