Chapter 4 Flashcards

1
Q

what is the most common solvant

A

water

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2
Q

true or false
Polar molecules only mix with polar molecules

A

true

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3
Q

what are the characteristics of a aqueous homogenous solution

A

its uniform throughout its appearance and the solvent is water

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4
Q

what are the two components of a solution

A

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

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5
Q

define electrolytes

A

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

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6
Q

what are the 3 types of electrolytes and their characteristics

A

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

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7
Q

how can a solution be oversaturated

A

when the compound has exceeded the solubility limit.

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8
Q

whats difference between molarity and molality

A

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

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9
Q

define mole and mass fraction

A

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

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10
Q

how can u find the concentrations of ions in a solution

A

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

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11
Q

what the purpose of a dilution

A

allows storage when doing mixtures

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12
Q

describes the process of a dilution

A

adding water to a stock solution, to obtain desired molarity

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13
Q

Why is the equality M1V1=M2V2 true in dilutions

A

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

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14
Q

define precipitation reactions

A

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

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15
Q

How to predict a precipitation reaction

A

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

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16
Q

what are the 3 ways of describing a reaction

A

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

17
Q

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

A

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

18
Q

define an arrhenius acid and base

A

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

19
Q

define a bronsted-lowry acid and base

A

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.

20
Q

whats the difference between a strong and weak acid

A

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

21
Q

state the strong acids

A

HCl, HBr, HI, HNO3, H2SO4, HClO4

22
Q

state the strong bases

A

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

23
Q

whats the difference between a strong and weak base

A

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

24
Q

whats a polyproptic acid

A

an acid that produces 2 or more acidic hydrogens per molecule

25
Q

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

A

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

26
Q

define titration process

A

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

27
Q

whats the difference between the equivalence point and endpoint

A

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.

28
Q

what are the characteristics of an oxido-reduction reaction

A

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

29
Q

whats the pH

A

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

30
Q

how does the hydronium ion concentration affect the pH

A

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

31
Q

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

A

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

32
Q

what are the rules for assigning the oxidation state

A

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

33
Q

Define the 4 main concepts of oxido-reduction reactions

A

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.

34
Q

step for balancing reddox reactions

A

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