Unit 4: Chemical Reactions

physical change

change to appearance without changing the identity (crushing, tearing, melting, boiling etc.)

chemical change

change that transforms into a different substance (burning, decomposing, cooking)

molecular equation

a regular chemical equation

complete ionic equation

the ions of aqueous ionic compounds are written out individually

net ionic equation

like the complete ionic equation but removes “spectator ions” that do not react (from both sides of the equation)

percent yield

experimental/theoretical * 100

experimental = measured

theoretical = calculated

percent error

| experimental - theoretical |/theoretical *100

experimental = measured

theoretical = calculated

titration

determines concentration of unknown acid/base (analyte) by reacting with known concentration of acid/base (titrant)

equivalence point

point where analyte has completely reacted, no excess titrant

end point

point where indicator changes color

should be at or near equivalence point

redox reactions

reactions where electrons are transferred between chemical species

elemental on one side - compound on the other

activity series trend

top - less stable, naturally occur as compounds (NEED FRIENDS)

bottom - more stable, naturally occur as elements (LONELY)

do strong acids and bases extensively ionize in water? do you write them as separate ions when aqueous?

yes ~100%, yes write them separately

do weak acids and bases extensively ionize in water? do you write them as separate ions when aqueous?

no ~<1%, no write them together

acid base reactions typically produce?

water and a salt

bronsted lowry acid

can donate a proton

bronsted lowry base

can accept a proton

conjugate acid

result when a base accepts a proton

conjugate base

result when an acid donates a proton

amphoteric molecules

can act as an acid or base (like H₂O, or HCO₃

how do you know which amphoteric molecule is going to act as the acid and which is going to act as the base?

stronger acid = acts as acid

stronger base = acts as base

look at the product and see which one donated an acid or gained an acid

negatively charged ions are…

basic (except for ones in strong acid/base)

positively charged ions are…

acidic (except for ones in strong acid/base)

oxidation?

lose e, # increases

reduction?

gain e, # decreases