solubility Flashcards
aqueous solution
when water is used to dissolve a solid, liquid or gaseous substance
solute
a chemical that is dissolved in a solution
solvent
the substance in which the solute dissolves in, often a liquid
how come polar molecules dissolve in water
because they are able to form hydrogen bonds with water molecules or the molecules can ionise in the water
for a solution to be aqueous
the solvent must be water
homogenous solution
the solute and solvent cannot be distinguished from each other visually, every part of the solution looks the same as every other part
characteristics of solutions
homogenous, dissolved particles are too small to see, the amount of dissolved solute can vary from one solution to another
what is the process of dissolving also called
dissolution
following processes occur in dissolution
solute particles are attracted to some of the solvent particles, the particles of the solute are seperated from one another, some of the solvent particles are seperated to allow the solute particles to disperse throughout the liquid
what are the different forces of attraction that need to be considered when a substance is determined to dissolve in water
the forces holding the particles of the substance/solute together before its added to the solvent, the forces holding the solvent molecules together, the forces that can form between the solute particles and solvent molecules
what forces are between water molecules
hydrogen bonds and dispersion forces
for a substance to dissolve…
the attractive forces between the solute and solvent particles must be similar to oor greater thaan the forces between the particcles in the solute and the forces between the solvent molecules
how come wax and other non-polar substances not dissolve well in water
only intermolecular forces between these substances are dispersion forces whereas hydrogen bonds exist between water molecules, they are much stronger than the forces of attraction that could occur between water molecules and these substances , so the forces of attraction between the water molecules cannot be overcome
when tthe two substances in the dissolving process are liquids they are
misicble
when the two liquids do not dissolve each other they are
immiscible
three ways that compoudds dissolve in water
- by forming hydrogen bonds, 2. ionisation (formation of ions) 3. ionic compounds dissolve by ddissociation
ethanol structure
C2H5OH, liquid at room temp, its molecules contain the polar OH group with lone pairs of electrons on the oxygen atom
how can ethanol dissolve in water
the hydrogen bonded to the oxygen allows the foormation of hydrogen bonds, the strength of the solute-solute intermolecular forces are similar to the solute-solvent intermolecular forces
polar molecule dissolving in water
the equation for dissolution place h20(l) above the arrow as no chemical change occurs
what makes a polar moolecule less and more dissolving
the more polar the molecule, the more likely it will dissolve in water, the larger the non-polar section of the molecule the less likely it will dissolve
when does ionisation in water occur
when the solute compound has one or more covalent bonds that are so polar they break when the compound is placed in water
HCl + water forms
cl- ions and h3o+ ions
HCL is said to ionise in water because
the Hcl molecule has broken apart to produce ions
H3O+ bondiing
beconmes hydrated, three of the oxygens of h2O bonds to the hydrogens of H3O, one oxygen of H2O bonds to the hydrogen of H3)
Cl- bonding when hcl dissolves
surrounded by six hydrogens from h2o bonded to the cl, described as hydrated
is water included in the hcl and water reaction
yes as a reactant because there has been a chemical reaction/rearrangment of atoms to form new substances
when does dissociation occur
when there are soluble ionic compounds
what occurs when sodium chloride/ionic compound is added to water
the positive eds of the water molecules (hydrogens) are attracted to the negatively charged chloride ions, the negative end of the water molecules (oxygen) is attracted to the positive sodium ions
what attraction oxxurs between an ion and polar molecule such as water
ion-dipole attarction
what is ionisation, refering to sodium chloride
water molecules are in a constant stae of random motion, if the ion-dipole attarction is strong enough, the water molecules can pull the sodium and chloride ions on the outer part of the crystal out of the lattice and into the surronding solution
