unit 4 test Flashcards
results a chem rxn took place
the temp of the rxn mixture increases
is conducting electricity a sign if a chem rxn
no becuase if the initial solutions are ions they will anywyas
what is the best way to determine a change occurred when water and X are mixed
measure the electrical conductivities of water and X mixture
what is a compound that is an electrolyte
an ion compound
strong electrolytes
strong acids bases and ionic compounds
non electrolytes
covalently bonded molecular substances
except acids and bases
weak electrolytes
weak acids
weak bases
what is always a product for any combustion reaction
H2O is always a product in a combustion reaction
what is broken in a chemical change
covalent and ionic bonds
physical change breaks what attractions
intermolecular
chemical change breaks what attractions
intra molecular attractions
evidence of chem change
production of gas formation of precipitate or solid change in color production of heat- combustion produces heat sounds light
for strong electrolytes to be separated into ions they have to be in what state of matter
they have to be aqueous
strong electrolytes
are soluble ionic substances
know your 7 strong acids
know your 7 strong bases
know your polyatomic ions memorized
ok
what happens to weka electrolytes
nothing they remain in tact(since they ar won’t aqueous?)
as soon as you are given a particle diagram
count the number of particles
circle the groups based on the balanced equation
always use law of conservation of mass
products equals reactants
molar volume is used to
convert between moles and literdy
what is molar volume
22.4 mol/1 L at STP
what is density
grams per litee
what is percent yield
what you got in the lab over what you are supposed to get based on stoich times 100
the point of a titration
determine the mass of an unknown
analyze
what we are analyzing with the unknown concentration
titrant
in the burrette what we have a known concentration of
burrette
most precise piece of glassware in a lab
equivalence point
when the analyte is totally consumed by the titrant
end point
when the color has changed
based on the volume of the flask and the volume of what is in the burrette you cna
determine the concentration at equivalence point
precipitation reaction is a
DR (double replacement) reaction that creates a solid
acid base reaction
a neutralization reaction where an acid donates a proton and a salt and water are formed
neutralization run means
we form water
redox
involves transfer of electrons
combustion runs are
a subclass of redox reactions carbon and water are always formed
an acid according to bronsted lowry
an acid is. proton donor
base according to bronsted lowry
proton acceptor
what is an amphoteric substance
water, it cna be an acid or a base
what are elements
substances that can’t be decomposed into simpler substances by chemical or physical means
what is important to to note about physical changes
they are usually reversible
Na + Cl2 -> NaCl
composition (synthesis) rxn
KClO3 -> KCl + O2
Decompostion
Mg+HCl-> MgCl2 + H2
single ionic replacement
LiCl + AgNO3 -> LiNO3 + AgCl
double ionic replacement
C3H8 + O2 -> CO2 + H2O
combustion of a hydrocarbon
Mg + O2 -> MgO
combustion of a metal
what reaction is NOT a double replacement rxn
redox rxns
gas to liquid
condensation
liquid to gas
vaporization
solid to liquid
fusion(melting)
liquid to solid
freezing
solid to gas
sublimation
gas to solid
deposition
7 diatomic elements
H2 N2 O2 F2 Cl2 Br2
dissolution example w ionic and strong acids and bases
NaCl(s)->NaCl(aq)
NaCl(s)-> Na+(aq) + Cl-(aq)
dissolution example: non ionic and weak acids/bases
C6H12O6(s) -> C6H12O6(aq)
no change
C6H12O6(s) -> C6H12O6(aq)
the theoretical yield is also the
limiting reactant
acid base titration
either acid or base is titrant, pH meters cna determine equivalence point
redox titration
a color change is produced when oxidation state of a metal ion in the rxn changes
precipitation titration
when the titrant reacts w ions in the analyze a precipitation can occur
how will a strong acid or base act in water
it will completely ionize or be soluble
how will a weak aoc dot base act in water
it will have less than 100% ionization
strong acids
HClO3 HBr HCl HI HNO3 HClO4 H2SO4
strong bases
LiOH NaOH KOH RbOH Ca(OH)2 Sr(OH)2 Ba(OH)2
a strong acid forms a
a weak conjugate base and vice versa
a weak acid forms a
strong conjugate base and vice versa
What happens to the IMF
melting
weakening
What happens to the IMF
boiling
breaking
What happens to the IMF
condensing
forming
What happens to the IMF
sublimation
breaking
What happens to the IMF
deposition
forming
What happens to the IMF
freezing
forming
metal and strong acid form a
Mg+2HCl ->
salt and gas(usually H2)
MgCl2 + H2
carbonate and strong acid form a
MgCO3 + HCl ->
combustion reaction is an ion in addition to water and carbon dioxide
MgCl2+H2O +CO2
weak electrolyte have
partial dissociation
strong electrolytes have
complete dissociation
completing the following equations for an ionic compound place in water means
do the mismatching compound thing and find the solubility of the products(should be aqueous)
usually decomposition or double replacement
is the LR bigger or smaller than the ER
the LR is smaller
what do you use to find the excess reactant
the limiting reactant
what type of compounds are non electrolytes
polar covalen
what types of compounds are weak electrolytes
weak acids
what type of compounds are strong electrolytes
ionic compounds
If acid/ base is stronger than CA/CB which direction does the reaction proceed
To the right
If CA/CB is stronger than the acid/ base which direction does the reaction proceed
To the left
What is a neutralization reaction
Acid reacting with a base
What are the products of a neutralization reaction
Salt and water
What si the net ionic reaction for any strong acid/strong base rxn
H+ +OH- -> H2O
What is a salt
A compound with no net charge, the opposing charges balance out
What elements tend to be good oxidizing agents
No metals
What elements tend to be good reducing agents
Metals
What does acid base titration do
It determines how much volume acid or base is in a solution
That will completely react with it
As we add base what happens to the pH
As the volum of the base increases the pH slowly rise then sharply increases at the equivalence point
What’s the titrant
The known concentration
What’s the analyte/titrand
The unknown solution your want to known the concentration of
What’s the point of a titration
Determine concentration of unknown solution by adding a concentration of a known solution
What does an indicator do
Mark the endpoint of a titration
As the volume of the titrant increases what happens to the color of the indicator
It appears then disappears as you swirl and infills it becomes a colored solution
Typically titrations are formed how many times
3 times and average volume is used
If a molecule is a weak acid what happens to it in a net ionic equation
Like HC2H3O2
You do not break it up for net charge because weak acids(or electrolytes) don’t fully dissociate or ionize
If HCl is an acid what is it’s conjugate
And why
Cl-
1 less H and 1 less charge
If H2O is a base what is its conjugate
H3O+
One extra H and one extra positive charge
Amohoteric
Substances that are able to act as an acid or base (water?)
What can MV = MV be used for
Determining molarity of unknown solution that reacts with known sokution(titration)
M is moles and v is volume in L
What does a non electrolyte do
Not dissociate at all
What does a weak electrolyte do
Some molecules dissociate some do not
What does a strong electrolyte do
Everything completely dissociates
What is the driving force in the net equation
Something that isn’t (aq) aka something that can’t be ionized and broken up in the net equation
When does M1V1=M2V2 work
In neutralization reaction
When there is one OH in one equation and one H in the other
1:1 ratio
What is a neutralization reaction
Moles of acid must equal moles of base
For solution equations first
Find the products side and balance the equation to use for mol ratio!
What product should you always try to get in a neutralization reaction
Water H2O
when u add base to a strong acid to a strong base solution what happens to the pH
it increases
when you add acid to a strong base to a a strong acid solution what happens to the pH
it decreases
in pH titration curve the volume corresponds to what
the titration in the left of the solution
the equivalence point occurs when the slope is
vertical
when calculating charges for redox rxns consider
the coefficient multiply the eco efficient by the charge!!
