Chapter 4 Flashcards
what is the most common solvant
water
true or false
Polar molecules only mix with polar molecules
true
what are the characteristics of a aqueous homogenous solution
its uniform throughout its appearance and the solvent is water
what are the two components of a solution
solvent: the major quantity
solute: in small quantity, the substance being dissolved.
define electrolytes
the substance that once mixed with water creates a solution that conducts electricity
what are the 3 types of electrolytes and their characteristics
strong electrolytes: conduct electricity very efficiently, dissolves completly as ions
weak electrolytes: conduct small amount of electricity, only small % dissolves as ions
non-electrolytes: cant conduct electricity
how can a solution be oversaturated
when the compound has exceeded the solubility limit.
whats difference between molarity and molality
molarity is the amount of moles in volume (mol/L) while molallity is amount of moles in mass of something (mol/kg)
define mole and mass fraction
mole fraction: mole intial/mole total
mass fraction: mass initial/mass total
how can u find the concentrations of ions in a solution
1- find molarity of solution
2-determine the balanced chemical equation where the compound in questions is dissolved in ions
3- multiply molarity of solution with coefficient of the ion
what the purpose of a dilution
allows storage when doing mixtures
describes the process of a dilution
adding water to a stock solution, to obtain desired molarity
Why is the equality M1V1=M2V2 true in dilutions
adding water doesn’t alter the amount of moles in the solution
n initial=n final
define precipitation reactions
double displacement reactions where a solid froms and separates from the solution, the solid is an insoluble compound that forms as the two solutions come in contact
How to predict a precipitation reaction
1- determine the product of the reaction
2- Balance the equation and assign states to every compound
3- Determine which compound is solid (precipitate), if everything is aq then no net ionic equation
what are the 3 ways of describing a reaction
1- Complete molecular equation: all compounds presents as reactants and products with their states
2- Complete ionic equation: every compounds is broken down in ionic form except solid and liquid compounds
3- Net ionic equation: contains the ions that participate in reaction. describes the reaction on ionic level
What do we call ions that are omitted from the NIE and why is that
Spectator ions, and they do not participate in the reaction.
define an arrhenius acid and base
acid: substance that produce H+ ions when dissolved in water
base: substance that produces OH- ions when dissolved in water
define a bronsted-lowry acid and base
acid: molecule/ions that gives a proton to another specie in proton transfert reaction
base: molecule/ions that gains a proton from another specie in proton transfert reaction.
whats the difference between a strong and weak acid
strong: completly ionizes in water, can’t reverse the process, strong electrolytes
weak: partly ionize, present as molecules and ions in water, weak electrolytes
state the strong acids
HCl, HBr, HI, HNO3, H2SO4, HClO4
state the strong bases
KOH, NaOH, LiOH, Ca(OH)2, Ba(OH)2, Sr(OH)2
whats the difference between a strong and weak base
strong: completly ionizes in water, can’t reverse the process, strong electrolytes
weak: partly ionize, present as molecules and ions in water, weak electrolytes
whats a polyproptic acid
an acid that produces 2 or more acidic hydrogens per molecule
What substances form gas when treated with an acid and what gases
sulfides, sulfates and carbonates which results in CO2, SO2 or H2S
define titration process
delivery of a measured volume of a solution with a known concentration (titrant) into a solution with substance that’s being analyzed (analyte).
whats the difference between the equivalence point and endpoint
equivalence point is when enough titrant has been added to react fully with the analyte (same amount of moles)
endpoint is an color indicator that tells us the equivalence point has been reached.
what are the characteristics of an oxido-reduction reaction
reaction where there a transfert of electron
oxydation reaction= loss of electrons= increase in oxydation state= reducing agent
reduction reaction= gain of electron= decrease in oxidation state= oxidizing agent
whats the pH
negative base 10 log of hydronium ion concentration
concentration H+ ions= 10^-ph
how does the hydronium ion concentration affect the pH
higher concentration then pure water= pH under 7 so acidic
lower concentration than pure water- pH above 7 so basic
what are the different ways to measure the pH of a solution
1- lithmus paper
2- color indicators
2- pH meters
what are the rules for assigning the oxidation state
1) elements in their natural form have an oxidation state of 0
2) monoatomic ions have an oxidation state equal to their charge
3) oxygen usually has an oxidation state of -2 except in peroxides where its -1
4) hydrogen has an oxidation stateof +1 except in binary compounds with metals, where its -1
5) fluorine has an oxidation state of -1, while other halogens have an oxidation state of -1 except when paired with oxygen or another halogen above them.
6) the sum of all oxidation states in a compound must equal 0
7) the sum of the oxidation states in a polyatomic ions must equal the overall charge of the ion
Define the 4 main concepts of oxido-reduction reactions
1) oxidation half reaction: loss of electron by a species
2) reduction half reaction: gain of electron by a species
3) oxidizing agent: oxidizes antother species while being itself reduced
4) reducing agent: reduces another species while being itself oxidized.
step for balancing reddox reactions
1- define whats being reduced and oxidized
2- determine the equations for the 2 half reactions
3- Balance the reactions according to the electrons
4-add the two half-reactions and balance according to the environnement
