Chapter 4

Question 1

what is the most common solvant

Answer 1

water

Question 2

true or false
Polar molecules only mix with polar molecules

Answer 2

true

Question 3

what are the characteristics of a aqueous homogenous solution

Answer 3

its uniform throughout its appearance and the solvent is water

Question 4

what are the two components of a solution

Answer 4

solvent: the major quantity
solute: in small quantity, the substance being dissolved.

Question 5

define electrolytes

Answer 5

the substance that once mixed with water creates a solution that conducts electricity

Question 6

what are the 3 types of electrolytes and their characteristics

Answer 6

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

Question 7

how can a solution be oversaturated

Answer 7

when the compound has exceeded the solubility limit.

Question 8

whats difference between molarity and molality

Answer 8

molarity is the amount of moles in volume (mol/L) while molallity is amount of moles in mass of something (mol/kg)

Question 9

define mole and mass fraction

Answer 9

mole fraction: mole intial/mole total
mass fraction: mass initial/mass total

Question 10

how can u find the concentrations of ions in a solution

Answer 10

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

Question 11

what the purpose of a dilution

Answer 11

allows storage when doing mixtures

Question 12

describes the process of a dilution

Answer 12

adding water to a stock solution, to obtain desired molarity

Question 13

Why is the equality M1V1=M2V2 true in dilutions

Answer 13

adding water doesn’t alter the amount of moles in the solution
n initial=n final

Question 14

define precipitation reactions

Answer 14

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

Question 15

How to predict a precipitation reaction

Answer 15

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

Question 16

what are the 3 ways of describing a reaction

Answer 16

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

Question 17

What do we call ions that are omitted from the NIE and why is that

Answer 17

Spectator ions, and they do not participate in the reaction.

Question 18

define an arrhenius acid and base

Answer 18

acid: substance that produce H+ ions when dissolved in water
base: substance that produces OH- ions when dissolved in water

Question 19

define a bronsted-lowry acid and base

Answer 19

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.

Question 20

whats the difference between a strong and weak acid

Answer 20

strong: completly ionizes in water, can’t reverse the process, strong electrolytes
weak: partly ionize, present as molecules and ions in water, weak electrolytes

Question 21

state the strong acids

Answer 21

HCl, HBr, HI, HNO3, H2SO4, HClO4

Question 22

state the strong bases

Answer 22

KOH, NaOH, LiOH, Ca(OH)2, Ba(OH)2, Sr(OH)2

Question 23

whats the difference between a strong and weak base

Answer 23

strong: completly ionizes in water, can’t reverse the process, strong electrolytes
weak: partly ionize, present as molecules and ions in water, weak electrolytes

Question 24

whats a polyproptic acid

Answer 24

an acid that produces 2 or more acidic hydrogens per molecule

Question 25

What substances form gas when treated with an acid and what gases

Answer 25

sulfides, sulfates and carbonates which results in CO2, SO2 or H2S

Question 26

define titration process

Answer 26

delivery of a measured volume of a solution with a known concentration (titrant) into a solution with substance that's being analyzed (analyte).

Question 27

whats the difference between the equivalence point and endpoint

Answer 27

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.

Question 28

what are the characteristics of an oxido-reduction reaction

Answer 28

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

Question 29

whats the pH

Answer 29

negative base 10 log of hydronium ion concentration concentration H+ ions= 10^-ph

Question 30

how does the hydronium ion concentration affect the pH

Answer 30

higher concentration then pure water= pH under 7 so acidic lower concentration than pure water- pH above 7 so basic

Question 31

what are the different ways to measure the pH of a solution

Answer 31

1- lithmus paper 2- color indicators 2- pH meters

Question 32

what are the rules for assigning the oxidation state

Answer 32

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

Question 33

Define the 4 main concepts of oxido-reduction reactions

Answer 33

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.

Question 34

step for balancing reddox reactions

Answer 34

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