Stoichiometric Relationships Flashcards
(45 cards)
What are the different changes of state
melting, freezing, vaporization (evaporation and boiling), condensation, sublimation and deposition.
What is a homogenous mixture
A homogeneous mixture is simply any mixture that is uniform in composition throughout. (components are combined)
what is a heterogenous mixture
A heterogeneous mixture is a mixture that composes of components that are physically separate
what do physical and chemical properties depend on
the way atoms combine
What is a mole?
a mole is the amount of substance that contains L particles of that substance.
The mass of one mole of any substance is known as the molar mass and has the symbol M.
What is the RAM
the relative atomic mass of an element (Ar) is the weighted mean of all the naturally occurring isotopes of the element relative to carbon-12.
Units: mol^-1 or Mr
-used to compare the masses of moles
What is avagadros constant for 1 mole
6.022 x10^23
what is avagadros law
THE EQUAL VOLUMES OF DIFFERENT GASES AT THE SAME TEMPERATURE AND PRESSURE CONTAIN THE SAME NUMBER OF MOLES
what does avagadros law explain
one mole of any gas will occupy the same volume at the same temperature and pressure. This is known as the molar volume of a gas.
what variables do you change for a fixed mass in gas
temperature (kinetic energy), volume(concentration of particles) and pressure( decrease in volume=increase in concentration=faster moving particles)
properties of chemical reactions
- new substances are formed
- bonds in the reactants are broken and bonds in the products are formed resulting in an energy change between the reacting system, and its surroundings
- there is a fixed relationship between the number of particles of reactants and products resulting in no overall change in mass- this is known as the stoichiometry of the reaction
State symbols
(s) -solid
(l) -liquid
(g) -gas
(ag) - in an aqueous solution
What 3 formulas for compounds exist
empirical, molecular, structural
what is the empirical formula
simplest whole number ratio of atoms of each element in a particle of substance
what is the molecular formula
shows the actual number of atoms of each element in a molecule of the substance. Can be obtained from the empirical formula if the molar mass of the compound is known.
what is the structural formula
-shows the arrangement of atoms and bonds within a molecule
properties of the solid state
- fixed shape
- fixed volume
- particles held together by intermolecular forces in a fixed position
- particles can vibrate about a fixed point but do not translational velocity
- as heat is supplied at a certain temperature the vibration is sufficient to overcome the attractive forces holding the solid together and the solid melts
properties of the liquid state
- fixed volume
- takes up shape of the container
- particles held closely together by intermolecular forces
- particles have translational velocity so diffusion can occur
- as heat is supplied the liquid particles move faster than others and escape from the surface of the liquid to form a vapour. Once the pressure of the vapour is equal to the pressure above the liquid; the liquid boils
properties of the gaseous state
- widely spaced particles that completely fill the container
- pressure of the gas due to gaseous particles colliding with the walls of the container
- intermolecular forces between particles negligible
- volume occupied by molecules themselves negligible compared with total volume of gas
- particles moving with rapid, random motion so diffusion can occur
units of molar mass (M)
g mol
what is a standard solution
a solution of known concentration, consisting of a solute and a solvent
what can can reactants sometimes be
limiting or excess (stoichiometry CHECK)
what is the experimental yield and the theoretical yield
experimental yield= substance produced in experiment
theoretical yield= substance on average theoretically produced
what is a mixture
when substances combine without chemical interaction
