Elemental phosphorus is made by heating calcium phosphate...

Elemental phosphorus is made by heating calcium phosphate with carbon and sand in an electric furnace. What is the weight percent of phosphorus in calcium phosphate? Use this value to calculate the mass of calcium phosphate (in kilograms) that must be used to produce $15.0 \mathrm{kg}$ of phosphorus.

Key Concepts

Stoichiometric Calculations

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. It encompasses the use of balanced chemical equations to relate the masses and moles of the substances involved. In problems where specific amounts of products are produced from given reactants, stoichiometric calculations ensure that the necessary proportions are accurately determined.

Mass Conversion Based on Composition

This concept involves using the weight percent composition of an element in a compound to perform mass-to-mass conversions. When a desired mass of a pure element is needed, knowing the weight percent allows one to calculate the necessary mass of the compound that contains that element, which is a common requirement in practical chemical manufacturing.

Molar Mass Calculation

This concept involves computing the molar mass of a compound by summing the atomic masses of all the atoms present in its chemical formula. It is fundamental in converting between the mass of a substance and the amount in moles, which is critical for quantitative analysis in chemistry.

Weight Percent Composition

Weight percent composition refers to the percentage of the total mass of a compound that is contributed by a particular element. It is calculated by dividing the total mass of the element in one mole of the compound by the molar mass of the compound and then multiplying by 100. This concept is essential for determining how much of each element is present in a compound.

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