Chapter 04: Chemical Quantities and Aqueous Reactions Flashcards Preview

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Flashcards in Chapter 04: Chemical Quantities and Aqueous Reactions Deck (68):
1

Stoichiometry

Quantitative relationships between products and reactants in chemical equations

Requires use of:
1) Balanced chemical equation
2) Conversion factor: mole ratios

2

Mole ratio

Ratio in units of moles relating any two species in a chemical reaction

Used as a conversion factor

 

3

Solving stoichoimetry problems

Mass (g) of compound A
to
Moles of compound A
using molar mass
Then to
Moles of compound B
using mole ratio
Then to
mass (g) of compound B
using molar mass

4

Limiting reactant (reagent)

Reactant that limits the amount of product that can be made

5

Excess reactant

Leftover reactant (not reacted) in a chemical reaction

6

Reaction yield: theoretical yield

The amount of product that would result if all the limiting reactant reacted

7

Reaction yield: actual yield

The amount of product that is actually obtained from a reaction

8

% yield

% yield =      actual yield        x 100
    theoretical yield

9

Solution

Homogenous mixture of 2+ substances

10

Solvent

Substance present in larger amount within solution

11

Solute

Substance(s) present with smaller amounts dissolved in solvent

12

Aqueous solution

Solution with water as solvent

13

Solution concentration

Qualitative and/or quantitative description of amount of solute in a solvent/solution

14

Molarity

Molarity (M) =       moles of solute (n)
                              liters of solution (V)

15

Dilute solution

Relatively small amount of dissolved solute

16

Concentrated solution

Relatively large amount of dissolved solute

17

Dilution

Procedure for preparing a less concentrated solution from a more concentrated solution

18

Dilution formula

M1V1=M2V2

Where   M = molarity
             V = volume

*moles (n) of solute remain the same

19

Solute and solvent interactions

Attractive forces between solute particles, between solvent particles, and between solute and solvent particles

If attractions between solute and solvent are strong enough --> dissolve

20

Charge distribution in water molecule

Oxygen = partial charge negative
Hydrogen = partial charge positive

21

Hydration

Process in which an ion is surrounded by water molecules arranged in a specific manner

22

Electrolyte

Substance that, when dissolved in water, conducts electricity

Contain cations and anions --> dissolve into ions
(Ionic compounds, some acids, some bases)

23

Nonelectrolyte

Substance that, when dissolved in water, does not conduct electricity

No cations, no anions
(Molecular substances)

24

Strong electrolyte

Dissolve completely as ions

*Irreversible reaction.

Most salts, some acids and bases

25

Weak electrolyte

Do not dissolve completely as ions

*Reversible reaction

26

Dissociation

Ions of a salt separate as salt dissolves

27

Ionization

Process of ion formation in solution
Results from chemical reaction between water + compound
(acids, bases)

28

Soluble

A compound that dissolves in water

29

Insoluble

A compound that does not dissolve in water

30

Solubility

The maximum amount of solute that will dissolve in a given quantity of solvent at a specifc temperature

31

Precipitation reactions & preciptate

Reactions that produce precipitate

&

An insoluble solid that separates from solution

32

Spectator ions

Ion that exists in the same form on both sides of chemical reaction

33

Complete ionic equation

Molecular equation's aqueous solutions are broken down to ions

Solids, liquids, and gases are still written as compounds

34

Net ionic equation

A complete ionic equation with spectator ions cancelled out

A shorthand way of showing what ions react

35

Gravimetric Analysis

Make aqueous solution with unknown substance

React unknown with known --> form precipitate

Filter & dry precipitate

Weigh precipitate

Use chemical formula and mass of precipitate to determine amount of unknown ion

36

Acid properties (6)

- sour taste
- blue litmus paper --> red (red means acid)


- reacts with certain metals to produce H2 (g) (as H is less reactive than most metals and displaced)
- reacts with carbonates and bicarbonates to produce CO2 gas
- reacts with bases to produce salt and water (neutralization)
- aqueous acid solutions conduct electricity
 

37

Base properties (5)

- bitter taste
- feel slippery
- red litmus --> blue (blue means base)

- reacts with acids to produce salt and water (neutralization)
- aqueous base solutions conduct electricity

38

Arrhenius acid

Produces H+ (H3O+) in water

39

Arrhenius base

Produces OH- in water

40

H3O+

Hydronium ion

Hydrated proton (i.e. H+ + H2O)

(Remember: H+ has 0 electrons, 0 neutrons, 1 proton)

41

Brønsted acid

Proton donor (donor = acid)

 

Must contain at least one ionizable proton

42

Brønsted base

Proton acceptor (acceptor = base)

43

Acid ionization

Acids = molecular compounds
Ionization = ion formation in solution from compound + H2O reaction

Thus:

- Acid molecules are pulled apart by attraction for water
- When acids ionize, H+ and counter anions form
- % of acid molecules that ionize varies

44

Strong acids

Acids that ionize virtually 100%

(Irreversible)

45

Weak acids

Ionize only a small percentage

(Reversible)

46

Monoprotic acids

Each unit of acid yields one H+ ion

47

Diprotic acids

Each unit of acid yields two H+​ ions

48

Triprotic acids

Each unit of acid yields three H+​ ions

49

Neutralization reactions

Acid + base --> salt + water

Weak acid + base --> salt + water

50

Gas-evolving reactions

Reactions that form gas directly (from ion exchange) or indirectly (from decomposition; reactants --> ion exchange --> gas + water)

 

acid + salt --> salt + gas + water

compared to

acid + base --> salt + water

51

Compounds that undergo gas-evolution reactions (4)

Sulfides --> H2S (g)

(Bi)carbonates --> H2CO3 --> CO2 (g)

(Bi)sulfites --> H2SO4 --> SO2 (g)

Ammonium --> NH4OH --> NH3 (g)

52

Oxidation-reduction reactions

(Redox reactions)

Electron transfer reactions

Uses chemical "bookkeeping" of election transfers

53

Oxidation half-reaction

Shows the loss of electron(s)

OIL = oxidiation is loss [of elections]

54

Reduction half-reaction

Shows the gaining of electron(s)

RIG = reduction igaining [of electrons]

55

Oxidation reaction

Half-reaction that involves loss of electron(s)

56

Reduction reaction

Half-reaction that involves gain of electron(s)

57

Oxidizing agents

Oxidizing agents are reduced and gain electron(s)

RIG = reduction is gain --> oxidizing agent reduces

58

Reduction agents

Reducing agents are always oxidized and lose electron(s)

OIL = oxidization is loss -- reducing agents oxidize

59

Combination reaction

Type of redox reaction

A + B --> C

60

Decomposition reaction

Type of redox reaction

C --> A + B

61

Combustion reaction

Type of redox reaction

A + O2 --> B

Substance + O2 --> [1+ O-containing substances] + water

Emits heat (exothermic)

62

Displacement reaction

Type of redox reaction

A + BC --> AC + B

3 subtypes:

Hydrogen displacement
Metal displacement
Halogen displacement

63

Activity series for halogens

F2 > Cl2 > Br2 > I2

Note: order from top to bottom = decreasing activity

Note: diatomic!

64

Disproportionation reaction

Type of redox reaction

Same element is simultaneously oxided and reduced

65

Titrations

Measure the volume of one reagent required to react with a measured mass or volume of another reagent

Often used to determine amount of acid or base in sample
Also used for redox reactions

Buret drips into Erlenmeyer flask

66

Indicator

Used in titrations to indicate when amount of known substance has neutralized unknown

67

Endpoint (equivalence point)

When an acid and base have become neutralized

68

Modified dilution equation

MacidVacid(# of H+) = MbaseVbase(# of OH-)