Stoichiometry: Calculations with Chemical Formulas and Equations

Flashcards covering key concepts from a Stoichiometry lecture, including the Law of Conservation of Mass, chemical equations, reaction types, formula weights, percent composition, moles, empirical formulas, stoichiometric calculations, limiting reactants, and yield calculations.

The Law of Conservation of Mass states that in all the operations of art and nature, nothing is ; an equal amount of matter exists both before and after the experiment.

created

In a chemical equation, appear on the left side of the equation.

Reactants

In a chemical equation, appear on the right side of the equation.

Products

tell the number of atoms of each element in a molecule.

Subscripts

tell the number of molecules.

Coefficients

In reactions two or more substances react to form one product.

combination

In a reaction one substance breaks down into two or more substances.

decomposition

reactions are generally rapid reactions that produce a flame and most often involve hydrocarbons reacting with oxygen in the air.

Combustion

A is the sum of the atomic weights for the atoms in a chemical formula.

formula weight

A is the sum of the atomic weights of the atoms in a molecule.

molecular weight

The equation for finding percent composition is: % Element = (number of atoms)(atomic weight) / ( ) x 100

FW of the compound

is 6.02 x 10^23.

Avogadro's Number

A is the mass of 1 mol of a substance (i.e., g/mol).

molar mass

In combustion analysis, C is determined from the mass of produced.

CO2

In combustion analysis, H is determined from the mass of produced.

H2O

The coefficients in a balanced equation give the ratio of of reactants and products.

moles

The is the reactant present in the smallest stoichiometric amount.

limiting reactant

The is the maximum amount of product that can be made.

theoretical yield

Percent yield = (actual yield / ) x 100

theoretical yield