Card Set Information
solutions chem test
components o solution (2)
solvent - medium solute dissolved in
solute - substance tt is dissolved in solvent e.g. salt
types o solutions (4)
gas in gas
gas in liquid
liquid in liquid
solid in solid
solutions in which water is solvent
transparent but can have colour
molc w/ uneven distribution o electrons
positive charge one side, negative other
molc which electrons even distributed among atoms, no charge
polar covalent bond can exist but no partial charge
attractive force BETWEEN molc
forces inside molc
strength o intermolc forces determine what physical properties o molec compounds (6)
hardness and texture
solubility in various solvents
What happens as intermolec frcs increase?
compound's melting point
surface tension all increase
list names intermolec forces (3)
london dispersion forces
intermolec frc attrtaction forms b/twn slightly positive end o one polar molc and slightly neg end another polar molc
more polar a substance, stronger dd force o attraction
london dispersion forces
weak attractive force acting between all entities caused by temp imbalance electrons
larger mol = more electrons/protons = stronger orces = higher melting pointf
unusually strong dipole dipole force b/twn hydrogen atom and FON, fluorine, oxygen nitrogen
What is frc called that combines dipole dipole and LDF?
van der waals forces
weak forces attraction between molc, includes ddf and ldf
quantity o given solute in solution
having relatively small quantity solute per unit vol o solution
having relatively large quantity o solute per unit vol o solution
3 types percentage concentration?
percentage weight by volume, g/100 ml
percentage volume by volume, ml/100ml
percentage weight by weight, g/100g
mass of solution is?
mass solute + mass solvent
How do you determine if dipole dipole frces are present?
if there's uneven uneven charges
if uneven charges cancel out, CO2, O2, no dipole dipole but can still be hydrogen bonding
use electroneg for EACH bond
Which compounds dissolve better?
molc compounbds w/ many hydrogen bonds
Why is water liquid at room temp?
strong intermolc forces
Why water successful solvent?
small in size, highly polar, capcity for hydrogen bonding
=signif for life on earth
High melting/boiling point allows
exist as liquid at room temp
keeps body fluids liquid over large range temps
cooling o water?
ice to float
water freezes top to down allows life underneath
pulls water into round droplets
high surface tension
allows water walking
inability to dissolve non-polar compounds
enables organisms to retain water (wax on leaves)
allows organisms to store non-polar substances (fats, oils)
separation o ions tt occurs when ionic compound dissolves
5 step dissociation process w/ water explain
1. water molc approaches crystal = reorient themselves b/c negative end water attracted to positive end ionic solid
2. water-ion attractions pull ions away from crystal while ionic bonds hold ions together
3. a) if attraction b/twn water and ionic solid = stronger than ionic bonds within ionic solid = dissolve
b) if not no dissolve
4. as ions leave leave crystal, surrounded by sphere water molc so can't attract each other again
Which substances don't dissolve well in water?
hydrocarbons b/c large, covalent bonds & non-polar
no attractive forces between water and hydrocarbons
other non-polar substances soluble in hydrocarbons
L-D forces loosely attract solute molc to hydrocarbon allowing it dissolve
bigger substances = bigger LD frcs
Why do solutes dissolve?
when attractive frcs b/twn solute and solvent = stronger than attractive frcs within either solute/solvent
molar concentration formula?
C n V triangle
C V Vsolv
#moles solute dissolved in 1L solution
process decreasing concen o aq solution by adding more water to small amount initial concentrated (stock) solution
formula for dilution questions?
ensure constant units
how to calculate grams o substance needed for stock solution?
find mole amount, CV = n
find grams, nM = m
max. amnt solute tt'll dissolve in givent amnt solvent, unit usually g solute/100 mL o solvent
solubility lvl o solvent hasn't been reached and if more solute added, will cont. to dissolve
solubility lvl o solvent just been reached and if more solute added = no dissolve
compounds w/ low solubility very little solute will dissolve 0.0001 mol/L
coumpounds w/ high solubuility lots o tt compound will dissolve 10.0 mol/L
3 factors that affect solubility
smalled molc often more soluble than bigger molc
depends on state
solids- solubility most solids increase w/ temp, increase temp = molc move faster causing solvent molc to hit solute molc more often breaks them apart faster
e.g. molecular, ionic
liquids - not generally affected by temp
gases - solubility gas decrease w/ high temp, trapped gas molc more opportunity to escape solvent
inverse linear relationship
solubility gas dependent on pressure gas above liquid
gas molc will move fr area high pressure to lower so if pressure outside solvent = higher, gas dissolves in
temp effect on polar molc, non polar
polar liquids solubility increase w/ temp
non-polar dont dissolve, immiscible (forms separate layer)
liquids w/ small amounts polar molc w/ hydrogen bonding dissolve in water, miscible (mix well in all proportions)
elements have low solubility in water e.g. carbon
halogens & oxygen dissolve to very tiny extent still reactive in small concentrations
total ionic equation
chemical equation tt shows all high solubility ionic compounds in their dissociated form
(aq) + NaCl
Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) -> Na+(aq) + NO3-(aq) + AgCl(s)
rewrite w/ charges, solids don't have
entity tt doesn't change or take part in chemical reaction
net ionic equation
way o representing reaction by writing only ions or neutral subst specifically involved in overall chemical reaction
Ag+(aq) + Cl-(aq) -> AgCl(s)
cross out spectator ions
What happens when two aqueous ionic compounds mixed?
compounds remain in solution, no reaction
one reactions with other -> precipitate, formation gas, or formation water (H+ and OH-)
how to find concentration ions in solution?
write with total ionic equation
always convert mL to L
what is used for very small concentrations?
parts per million
1 ppm = 1g/10^6 mL
what does M for solution represent?
if the question is asking for mass and solution what to do?
molar mass/ [ ]