unit 7 Flashcards
what is the law of conservation of mass?
in an enclosed system, matter cannot be created or destroyed
what is a chemical formula
a mole ratio of elements in a compound
what 2 things does a coeff. represent
number of atoms involved in a reaction
number of moles of the substance needed in a reaction
why do thes sum of the particles have to be the same
bc there must be the same number of particles for each element on both sides so totals will be the same
observable evidences of a chemical change
pH change, color change, change in flaming splint, pop noises
practice balancing equations also
if a compound is ionic what do u do first
balance charges
find the charge of both elements and switch them
synthesis
one product
decomposition
one reactant
single replacment
metal replacing cation in a compound
halogen replacing halogen (g17)
double replacment
compound + compound -) compound + compound
cations swap places
combustion
hydrocarbon + O2 -) CO2 + H2O
reduction
gaining electrons
oxidation
losing electrons
REDOX rules
elements=0
h=+1
f=-1
O=-2 (unless with F)
Halogen=-1 (O or F)
Group 16 = -2(O, F, or halogen)
Group 15 = -3 (unless with above)
elemtns can just be number too
percent yeild
a comparison of what is produced to what should be
experimental / theoretical x 100
experimental yeild
amount of product that is actually produced IS
theoretical yeild
amount of product that should be produced SHOULD
when it is a triangl H problem finding the energy what are the steps
grams to mols, mols to KJ
vice versa
KJ to mols, mols to grams
for litre equations what are steps
grams to mols, moles to moles, moles to Liters (treat as grams same set up)
there are four molecules of CH4 are combined with molecules of O2
1CH4 + 2 O2 -) 1CO2 + 2H20
Draw before and after particle diagrams what is limiting what is excess
ON PACKET
make sure group based on first part then draw off grouping
