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
- carbon dioxide
- 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)
- physical state
- melting point
- boiling point
- surface tension
- hardness and texture
- solubility in various solvents
What happens as intermolec frcs increase?
- compound's melting point
- boiling point
- surface tension all increase
list names intermolec forces (3)
- london dispersion forces
- dipole-dipole forces
- hydrogen bonds
- intermolec frc attrtaction forms b/twn slightly positive end o one polar molc and slightly neg end another polar molc
- relatively strong
- occur between all 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
- molecule size
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
- e.g. AgNO3(aq) + NaCl(aq) -> NaNO3(aq) + AgCl(s)
- 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
- use table
what is used for very small concentrations?
- parts per million
- 1 ppm = 1g/10^6 mL
- 1 ug/g
- 1g/ 1000L
- 1 mg/kg
what does M for solution represent?
if the question is asking for mass and solution what to do?
- molar mass/ [ ]