1 - Stoichiometry Flashcards
atom economy
a measure of the amount of starting materials that become useful products.
chemical element
a neutral substance that cannot be broken down into simpler substances using chemical methods
compound
a pure substance formed when two ore more chemical elements are chemically bonded together in fixed ratios
exothermic
release energy
endothermic
absorb/ require energy
sublimation
changing from solid to gas
deposition
changing from gas to solid
pure substance
an element or compound that has a definite and constant composition
mixture
a physical combination of pure substances which has no definite or constant composition e.g. homogeneous, heterogeneous. It can be separated into its pure components through filtration (seperate from liquid or gas), distillation (using different boiling points) and various forms of chromatography.
homogeneous mixtures
all the components are in the same phase
heterogeneous
the components are is different phases
mole
specific amount of a substance
Avogadro’s constant
is the number of atoms in 12g of Carbon-12
empirical formula
shows the simplest whole number ratio of atoms of each element in a particle of the substance
molecular formula
shows the actual number of atoms of each element in a molecule of the substance
theoretical yield
maximum amount of a product that could be formed according to the balanced equation
experimental yield
actual amount of product obtained when the experiment is performed
percentage yield
experimental yield divided by theoretical yield as a percentage