solubility Flashcards
what is a solute
a gas or solid that dissolves in a liquid, called the solvent
what are the solubility rules for ionic compounds in water
Solubility rules for ionic compounds in water:
Common sodium, potassium and ammonium compounds are soluble
* All nitrates are soluble
* Common chlorides are soluble, except those of silver and lead (Il)
* Common sulfates are soluble, except for those of barium, calcium and lead (Il)
* Common carbonates are insoluble, except for those of sodium, potassium and ammonium
* Common hydroxides are insoluble except for those of sodium, potassium and calcium (calcium hydroxide is slightly soluble).
what are the solubility rules for ionic compounds in water (name the soluble ones)
Solubility rules for ionic compounds in water:
Common sodium, potassium and ammonium compounds are soluble
* All nitrates are soluble
* Common chlorides are soluble, except those of silver and lead (Il)
* Common sulfates are soluble, except for those of barium, calcium and lead (Il)
what are the solubility rules for ionic compounds in water (name the insoluble ones)
- Common carbonates are insoluble, except for those of sodium, potassium and ammonium
- Common hydroxides are insoluble except for those of sodium, potassium and calcium (calcium hydroxide is slightly soluble).
- Common chlorides are soluble, except those of silver and lead (Il)
- Common sulfates are soluble, except for those of barium, calcium and lead (Il)
what is solubility
the measure of how much a solute can dissolve in a certain amount of solvent. it is measured in grams per 100g (or 100cm^3) of water
when can you describe a solid as soluble?
if it dissolves in a particular solvent
what does a solvent and solute make together
a solution
what is a saturated solution?
one in which no more solute can be dissolved in the solvent (when more solute is added it simply sinks to the bottom)
what is a solvent?
a substance that dissolves another substance, called a solute, to form a solution
what is a supersaturated solution?
when an object is heated up and cooled slowly so that added crystals grow
what does a solubility curve show? what does the actual curve show?
what mass of a solvent will dissolve in a solvent at a given temperature . the curve shows the no. grams of solute in a saturated solution contaiing 100ml or 100g of water at a certian temp
what does an amount of solute above/below the solubility curve indicate?
below-unsaturated at a certain temp
above-supersaturated
what does it mean if the solubility curve moves up/down
if it moves down it is likely the solute is a gas but if it is a solid it will move upwards
what happens if a solution is dissolved in water but cooled down (supersaturated)
it will come out of the solution/precipitate - not all would stay dissolved???
what is concentration?
the measure of the number of particles dissolved in a given volume
describe conc. in terms of acid in a bottle
if there are lots of acid particles and fewer water molecules, it is concentrated, if not it is dilute
what is conc. measured in?
mol/dm^3 or m (Molar)
what is Molar
the number of moles of a substance per 1 dm^3 of the solution it’s in
what is dm^3 to cm^3
10^3cm3 = 1 dm3
1cm3 x 1000 = 1dm3
describe the difference between conc. and strength.
strength is the extent to which an acid/alkali can dissociate (positive and negative bits break off) to produce H+ and OH- ions respectively. this si measured in pH. conc is the no of particles dissolved in a given volume
does conc. increase/decrease during evaporation?
it increases because the water particles evaporate but the solid particles stay
what is the equation linking moles, concentration, volume
moles = concentration x volume
n = cv
(mol) = (mol/dm3) x (dm3)
what is the conversion between g/dm3 and mol/dm3
g/dm3 = mol/dm3 x Mr
what is the equation linking moles, mass, and Mr?
n = mass/Mr
Mr x moles = mass
what is the equation linking n,c,v with changing, v/c
n1=n2
c1 x v1 = c2 x v2
v2 = c1 x v1/c2
what is conc(gdm3)?
Mr x conc (mol/dm3)
what is the equation linking moles, conentration, colume?
moles/volume (dm3) = conc (mol/dm3)
what is the gas equation?
n=v/24dm3
or vol in cm3/2400
give me a step by step of titration in order to make a salk
- use a pipette to put exactly 25 cm 3 of HCl (an acid) into a conical flask which is on a white tile
- take your solution of calcium hydroxide (alkali) and pour it into a burette. Note the starting volume.
- add a few drops (2-3) of a binary indicator, eg.g, phenolphthalein and slowly add the calcium hydroxide solution into the acid until the endpoint is reached when the indicator turns from colourless to pink
- repeat the experiment without the indicator (note volume of alkali required for neutralisation)
- once the solution is neutral, use a Bunsen burner to evaporate half of the water until the solution is saturated
- allow to cool and crystalise
- filter the solid calcium chloride
- pat the calcium chloride dry with filter paper
- transfer into a desiccator which is similar to an airtight container
give me a step by step of titration in order to find the unknown conecntration
- use a pipette to put exactly 25 cm 3 of HCl (an acid) into a conical flask which is on a white tile
- take your solution of calcium hydroxide (alkali) and pour it into a burette. Note the starting volume.
- add a few drops (2-3) of a binary indicator, eg.g, phenolphthalein and slowly add the calcium hydroxide solution into the acid until the endpoint is reached when the indicator turns from colourless to pink
- repeat until concordant results (0.2 cm3) results obtained
- calculate agreave titre (av. change in volume)
what does an acid and metal hydroxide make?
acid+ metal hydroxide = salt + water
what does an acid and metal make?
acid+ metal hydroxide = salt + hydrogen
what does an acid and metal carbonate make?
acid+ metal carbonate = salt + water + carbon dioxide
what is an acid?
a proton donor (A species that donates H* ions (protons))
what is a base
a proton acceptor (A species that accepts H* ions (protons))
what is a salt?
A compound where the H* from an acid has been replaced by a metal or other positive ion
what is solubility?
A measure of the maximum amount of solute (in gl that can be dissolved per 100g of solvent
what is a saturated solution?
A solution in which no more solute can be dissolved
what is crystalisation?
- A process whereby solid crystals form from a cooling solution because the amount of dissolved solid was greater than the solubility at a lower temperature
what colour does litmus go?
red in acids, purple in neutral solutions, blue in alkaline solutions
what colour does methyl orange go?
red in acidic solutions, yellow in neutral and alkaline solutions
what colour does phenolphthalein go?
colourless to pink (acid-alkaline)
what is the reaction between a base and an acide
a neutralisation reaction
what can Neutralisation reactions in aqueous solutions also be shown as?
ionic equation in terms of H+ and OH- ions
(H+ + OH- -> H2O)
what happens in a neutralisation reaction?
the OH ions are equal to the concentration of hydrogen ions
awhat cann all acids do?
ionise/ dissociate in solution which means splitting up a hydrogen ion and another ion e.e.g, HCl -> H+ + CL-
waht does acid strength mean?
what proportion of the acid molecules ionise in water
what is the difference between weak and strong acids?
stong acids almost completely ionise in water so they dissociate to release h+ ions whereas weak acids don’t fully ionise.
wht is the ionisaiton of a weak acid?
a reversible reaction, which sets up an equilibrium. only a few of the acid particles release H+ ions to the equilibrium lies far to the left
how does concentration affect PH?
if the conc of H+ ions increases by a factor of 10, the pH decreases by 1 so if conc increases by 100 (10x10) the pH decreases by 2 (1+1)
what is the difference between a soluble and insoluble salt?
when the two solutions are mixed, a salt will form a precipitate (insoluble) or just a form in solution (soluble salt)
how do you make an insoluble salt?
using a precipitation reaction where you pick two soluble salts and react them together to make an insoluble salt
how do you make a soluble salt?
using an acid and an insoluble base
