Unit 1-6 basic chem ccm test 1
percent composition
% of element= mass element/mass compound x100%
% mass by element
%mass by element= (# moles of element)(mm)/(1 mole)(mm of compound)
cation
(+) metal loses electron -smaller than parent bc looses electrons
anion
(-)non metal gains electron -larger than parent bc gains electron
temp conversions
(formulas in green packet:)
electronegativity trend
- ability of atom in molecule to attract electrons to itself up, right - increases as size decreases smaller atom attract neighboring electrons
ionization energy trend
- energy req move least tightly bound electron from atom up, right
ionic compounds
- have cation and anion -high melt points using formula unit subscripts are smallest whole num possible
ionic compound naming
- metal or polyatomic ion -if in group 1a, 2a, or Al, Cd,Zn = NO ROMAN NUMERAL -others need roman numeral hydrogen is nonmetal "end in ate and ite"
molecular compounds
- molecular formula -need prefix
group 5a, 6a, 7a gain electron
5a= -3 6a=-2 7a= -1
protons
= atomic number
transition metals form cations except:
Ag, Zn ^2, Cd^2
6 strong acids**
Hcl, Her, Hi, Hno3, H2so4, Hclo4 turn into ions when dissolved -produces hydrogen atoms when dissolved in water
amu
atomic mass unit 1amu=1.66x10^-24g
neutrons
atomic mass- atomic number
isotopes
atomic number is same atomic mass is diff -diff isotopes of element not equally distributed
periodic table: row (left to right)
called period every atom in period has same valence electrons
molecular formula
can be simplified
law of conservation of mass
can't be created or destroyed
empirical formula
can't be simplified to whole numbers
energy
capacity to do work
double displacement reactions
cations and anions are switched ex; ax+by-> ay+bx
water chem prop
decomposed using electricity reacts with sodium and potassium reacts with carbon mon at high temps
prop of matter: extensive properties
depends on amount of substance ex:mass/volume
volume displacement
displaced is volume of solid
atomic radius trend
distance from atom nucleus to valence electrons - down, left
groups( vertical columns)
elements in each group similar chemical and physical prop
kinetic energy
energy of motion ex: in the middle of a dive
pure substance
every sample is same unique set of properties element or compound
decomposition reactions
form simpler compounds ex:ab_> a +b
Polyatomic ions
green sheet, 2+ covalently bonded atoms
*strong bases to know
group 1a and 2a metals nah, lioh, koh, ca(0h)2, ba(oh(x, sr(oh)2
metalloids
have some properties of both ^ -electrical/thermal conduction increases with increasing temp
activity series chart
higher in series, more active than one below and will kick it out of compound
accuracy
how close measurement is to true value
precision
how reproducible multiple measurements of same thing are
polyatomic ions
hydroxide cyanide
metals
left of stair line solid room temp high luster ductile, malleable high melting points, form ions by loosing electrons can't combine with each other
adding/subtracting with sig figs
lesser amount after decimal is the amount should be in answer
chem change
makes new substance ex:rusting of iron
stoichiometric equivalencies
many moles of each element contained in a compound there are in one mole of the compound ex: 9mol carbon in c9h804
isotopic designation
mass number charge element symbol atomic number
Density
mass(g)/volume(mL)
prefixes
mono di tri tetra penta hexa hepta octa nona deca
scientific notation : moving decimal to right
negative exponent
heterogenous mixture
nonuniform composition ex:sand+water, iron+sand
prop of matter: intensive properties
not depend on amount ex:density, bp, mp, color
single displacement reactions
one element displaces the other, depends on reactivity - ex: ax+y _> ay+ x(anion rep) ax+b->bx+a (cation rep)
polyatomic molecules
p4 s8 03
scientific notation: moving decimal to right
postive exponent
mixture
pure substance that was physically combined homogenous heterogenous
combustion reaction
reaction of an element with oxygen -can also be a synthesis
single displacement continued
replacement of halogen by more active halogen replacement of hydrogen in acid by metal replace hydro in water by metal real of metal by more act metal
atom
retains chemical prop of that element
non metals
right of stair line all states of matter, low luster poor electrical, thermal conductivity not ductile, low melting points, form ion by gain electrons, combine with metal, metalloid, non metal
law of constant composition
same proportions of mass elements
element
simplest form of matter made up of 1 unique atom, can't be broken by chemical/physical methods
potential energy
stored energy ex:standing before dive
chemistry
study of properties of matter/changes it undergoes - changes through atoms bonding
physical change
substance changes physical appearance wo altering identity ex: freeze, dissolving
Dimensional analysis
sucks, practice it!
electrons
take atomic number, figure out charge( + subtract from atomic number, if - add to atomic number= electrons)
homogenous mixture
uniform every sample is same ex:air, salt water, bronze
multiply/divide with sig fig
amount with least amount sig fig for answer
7 Diatomic elements
02 n2 f2 cl2 br2 I2 H2
3 rules to displacement
1- solid must be more dense than water 2- solid can't dissolve in liquid 3- solid can't react with liquid
zero rules for sig fig
1- zeros btw always signif ex: 203= 3 sig fig 2- zeros w/o non zero in front not sig ex:0.1=1 sig fig 3- zeros end number with decimal are sig ex: 125.00= 5 sig fig 4- assume 0s end number w/o decimal not sig ex: 1200= 2 sig fig
5 methods of separating mixtures
1-evaporation 2-distillation 3-chromotography 4-filtering 5-centerfigation
density of water
1.0 boiling pt-100 degrees celsius freezing-0 degrees celsius
1a- 2a- 7a- 8a-
1a- alkali metals 2a-alkaline metals 7a-halogens 8a-noble gases
group 1a, 2a and 3a loose electron so
1a= +1 2a= +2 3a= +3
1 megaton
1x 10^6 tons
1 deci
1x10^-1m
1 centi
1x10^-2m
mili
1x10^-3m
micro
1x10^-6m
nano
1x10^-9 m
1 kilo
1x10^3 g
molecular compound naming
2 nometals or nonmetals/metalloid -need prefix -end in "ide"
synthesis reaction
2 or more substances combine to form a new one na+cl->nacl
compounds
2+ elements, whole number ratios held by chemical bonds ex:nacl -can be separated by chemical methods