Chapter 3 - Stoichiometry Flashcards
Reactant
Substances that are consumed in a chemical reaction
Chemical Equation
Describe proportions of reactants & products during a chemical reaction
Products
Substances that are formed in a chemical reaction
Combination Reaction
A type of chemical reaction where two (or more) substances combine to form one product
Mole
The SI base unit for expressing quantities of substances
1mole = 6.022 x 10^23 particles (Avogadro’s number)
Avogadro’s Number (NA)
The # of carbon atoms in exactly 12 grams of carbon-12 isotope
NA= 6.022 x 10^23
The # of particles in 1 mole
Mole as a Conversion Factor
Particles –> Moles
Particles x 1mol/6.022x10^23
Moles –> Particles
Moles x 6.022x10^23/1mol
Molar Mass (M)
(g/mol)
The molar mass of an element in grams per mole is numerically equal to that element’s average atomic mass in amu
Average mass of one atom = amu
Mass of one mole = gram
Molar mass = g/mol
Molecular Mass
The mass of one molecule of a molecular compound
The same as the molar mass of a compound (the molar masses of each element added up)
Formula Mass
Mass in amy of one formula unit of an IONIC COMPOUND
Basically the molar mass of the compound
Conversions Moles –> Mass
Moles x #g/1mol = grams
Grams x 1mole/#g
Law of Conservation of Mass
The sum of the masses of the reactants in a chemical reaction is equal to the sum of the masses of the products
Stoichiometry
The quantitative relation between the reactants in a chemical reaction
Indicated in chemical equations by coefficients (Basically proportion that the reactants are in)
Balanced Equation
Has the same number of atoms of each type on both sides of the equation
Follows the law of conservation
Combustion Analysis
A laboratory procedure for determining the composition of a substance by burning it completely in oxygen to produce known compounds whose masses are used to determine the composition of the original material
Hydrocarbons
A class of organic compounds containing molecular compounds composed of only hydrogen and carbon
When then combustion of a hydrocarbon is complete, the only products are carbon dioxide & water
Combustion Reaction
A reaction between oxygen & another element or compound that produces heat
The Carbon Cycle
Photosynthesis & respiration are key reactions in the carbon cycle
Photosynthesis
Plants convert CO2 & H2O into glucose
Respiration
(Reverse of photosynthesis)
Living organisms use glucose as a source of energy
Percent Composition
The mass percentage of each element in the compound
Limiting Reactant
A reactant that is consumed completely in a chemical reaction
The amount of product formed depends on the amount of the limiting reactant available
Percent Yield
Actual yield/ theoretical yield x 100
Theoretical Yield
The calculated amount of product formed based on the amount of limiting reactant
Actual Yield
The amount of product obtained from a chemical reaction
It is often less than the theoretical yield
