water the universal solvent Flashcards
solvent
a substance, usually a liquid, which is able to dissolve a solute to form a solution
when solid, liquid or gas is dissolved in water
aqueous
An aqueous solution is a solution in which the solvent is water
solute
substance being dissolved
solution characteristics
-The solute and the solvent cannot be distinguished from each other (homogeneous)
-The dissolved particles are too small to see
-the amount of dissolved solute can vary from one solution to another
dissolution
the process of a substance dissolving in another substance
miscible
forming a homogeneous mixture when added together
steps of dissolution
1)the particles of the solute are separated from one another
2)The particles of the solvent are separated from one another
3)The solute and solvent particles are attracted to each other
Explain what can be concluded about the forces present between the solute and solvent particles
For a substance to be soluble, the solute-solvent interactions must be stronger than the solute-solute and solvent-solvent interactions
like dissolves like
-polar solvents will generally dissolve substances consisting of polar molecules or charged ions
-non-polar solvents can dissolve substances consisting of non-polar molecules
why do non-polar molecules not dissolve well in water?
hydrogen bonds between water molecules are much stronger than the dispersion forces that could occur between molecules of oil and water.
as a result water molecules do not separate
examples of miscible and immiscible liquids in water
miscible: ethanol
immiscible: hexane
Importance of the solvent properties of water
Biological context:
-water provides a system to transport nutrients and soluble wastes
-Essential nutrients dissolve in water and are carried to organs
-nutrients in the soil are dissolved in water and are absorbed into the root system of plants
how does ethanol dissolve in water?
1) water molecules break
2)ethanol molecules break
3)ethanol and water molecules form
C2H5OH(l)——C2H5OH(aq)
(with h2o (l) on the arrow)
When hydrogen chloride dissolves in water:
1)polar covalent bonds within hydrogen cholride molecules break producing hydrogen ions (H+) and chloride ions (Cl-)
2)a covalent bond between H+ and H20 forms, forming H3O+ ions
3)ion-dipole attractions form between the H3O+ and CL- ions and polar water molecules
HCL(g)+H2O(l)—-H3O(aq)+Cl-(aq)
hydrate
an ion surrounded by water molecules. Hydrated ions can be found in aqueous solutions
dissociation
The separation of positive and negative ions as an ionic lattice melts or dissolves
How does sodium chloride dissolve in water
1) ionic bonds within the sodium chloride lattice are broken
2) hydrogen bonds between water molecules are broken
3) ion-dipole attractions form between ions and polar water molecules
NaCl(s)—–Na+(aq)+Cl-(aq)
can a substance be completely soluble or in soluble?
substances are rarely ever completely soluble or insoluble. The solubility of substances can be considered as a scale
SNAPE rule
Soluble salts:
Sodium (Na+)
Nitrates (NO3)-
Ammonium (NH4)+
Potassium (K+)
Ethanoate (CH3COO)-
precipitation reaction
when ions in a solution combine to form a new compound that is insoluble in water.
precipitate
The solid formed in a precipitation reaction is called the precipitate.
what are precipitation reactions used for?
-removal of minerals from drinking water
-remove heavy metals from wastewater
-purification plants of reservoirs
spectator ions
-an ion that remains in a solution and doesn’t change in the course of the reaction
-it is not included in the ionic equation
