Chem final exam

What is the periodic law

when elements are arranged in order of increasing atomic number, the properties of the elements repeat periodically (in a set pattern)

What is the octet rule

All elements tend to lose, gain, or share electrons to get 8 valence electrons so that they can be stable like a noble gas

How is Mendeleev’s table similar to our current table?

mendeleev’s table has the same physical and chemical properties as the current table

how is mendeleev’s periodic table different from our current table?

the current table is organized in atomic number instead of increasing atomic mass like mendeleev’s.

what is a valence electron?

electrons in the outermost energy level of an atom

what happens to electrons when an ionic bond forms

the electrons are being transferred so that each atom has the stable octet (zero or 8 valence electrons)

what happens with electrons when a covalent bond forms

they are being shared by atoms to try and get 8 valence electrons like a normal gas

which 3d sketch is this?

linear

which 3d sketch is this?

trigonal planar

which 3d sketch is this?

tetrahedral

which 3d sketch is this?

trigonal pyramidal

which 3d sketch is this?

bent

what are kinetics?

the rate at which reactions occur

what is a mechanism?

a set of steps that can occur to produce a chemical reaction

what is an intermediate?

a substance formed in one step of a mechanism but used up in another step

what is activation energy?

the minimum amount of energy necessary for a reaction to occur

what is a catalyst?

a substance that can change the rate of a reaction without being consumed in the reaction

what are the two characteristics a collision needs to have in order to produce a reaction?

enough energy and the correct orientation

how does surface area affect the rate of a chemical reaction?

increases the surface area of the solid and increasing the rate

how does temperature affect the rate of a chemical reaction?

increases the kinetic energy of the particles, moving faster and colliding more often

how does concentration affect the rate of a chemical reaction?

more particles will be available to collide with, meaning collisions will be more successful and the reaction rate will increase.

how does a catalyst affect the rate of a chemical reaction?

reduces activation energy, providing alternate reaction mechanisms

what is a chemical equilibrium

a dynamic state (constantly changing) in which two opposing reactions are happening in the same container at the same rate

what does lechatelier’s principle say?

if an equilibrium system is subjected to a stress, the equilibrium will shift to relieve the stress

what is the difference between forward and reverse reactions?

forward begins rapidly, decreases until equilibrium, reactants turn into products

reverse begins at zero, increases until equilibrium, products turn into reactants

what is a solution?

a mixture that is the same throughout

what is the difference between a solute and a solvent?

solute dissolves in a substance, there is less of it

solvent is the solution the solute dissolves in, there is more of it

what is a saturated solution?

the maximum amount of dissolved solute the solvent can hold under the given conditions

how is a unsaturated solution different from a saturated solution?

less than the maximum amount of dissolved solute

how is a superaturated solution different from a saturated solution?

supersaturated has more than the maximum amount of dissolved solute

what would happen if you added an extra crystal of solute to a saturated solution?

it would sink to the bottom but not dissolve

what would happen if you added an extra crystal of solute to a supersaturated solution?

extra crystals will appear

what kind of compounds are electrolytes?

ionic compounds

what do electrolytes do in water?

break apart into separate ions or atoms and conduct electricty

what kind of compounds are nonelectrolytes?

they don’t break apart into separate ions or atoms and they don’t conduct electricity

how can you tell if an object is in motion?

if its distance from another object is changing

what is the difference between average and instantaneous speed

average