AP Chemistry Mass Composition

What is percent composition?

• The mass of an element in a compound divided by the total mass of the compound, multiplied by 100%

• The mass of a compound divided by the total mass of the elements in the compound, multiplied by 100%

• The mass of an element in a compound divided by the total mass of the elements in the compound, multiplied by 100%

• The mass of an element in a compound divided by the total mass of the compound

What is stoichiometry?

• The study of the composition, structure, properties, and reactions of matter

• The study of the mass relationships and calculations of reactants and products in chemical reactions

• The study of the energy changes that occur during chemical reactions

• The study of the behavior of gases

What is the formula for percent composition?

• Mass of element / Mass of compound

• Mass of compound / Mass of element

• Mass of element / Total mass of elements in compound

• Total mass of elements in compound / Mass of element

What is the formula for stoichiometry?

• Mass of reactant / Mass of product

• Moles of reactant / Moles of product

• Volume of reactant / Volume of product

• Concentration of reactant / Concentration of product

What is the unit for percent composition?

• g

• g/mol

• %

• mol

What is the unit for stoichiometry?

• g

• g/mol

• %

• mol

What is the purpose of percent composition?

• To determine the empirical formula of a compound

• To calculate the molar mass of a compound

• To balance chemical equations

• To calculate the density of a compound

What is the purpose of stoichiometry?

• To determine the empirical formula of a compound

• To calculate the molar mass of a compound

• To balance chemical equations

• To calculate the density of a compound

What is the relationship between moles and mass in stoichiometry?

• 1 mole of a substance is equal to its molar mass in grams

• 1 mole of a substance is equal to its atomic mass in grams

• 1 mole of a substance is equal to its molecular mass in grams

• 1 mole of a substance is equal to its formula mass in grams

What is the relationship between volume and moles in stoichiometry?

• 1 mole of a gas occupies 22.4 liters at STP

• 1 mole of a gas occupies 24.0 liters at STP

• 1 mole of a gas occupies 1.00 liter at STP

• 1 mole of a gas occupies 2.00 liters at STP