Chapter 04: Chemical Quantities and Aqueous Reactions

Question 1

Stoichiometry

Answer 1

Quantitative relationships between products and reactants in chemical equations

Requires use of:

1) Balanced chemical equation
2) Conversion factor: mole ratios

Question 2

Mole ratio

Answer 2

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

Used as a conversion factor

Question 3

Solving stoichoimetry problems

Answer 3

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

Question 4

Limiting reactant (reagent)

Answer 4

Reactant that limits the amount of product that can be made

Question 5

Excess reactant

Answer 5

Leftover reactant (not reacted) in a chemical reaction

Question 6

Reaction yield: theoretical yield

Answer 6

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

Question 7

Reaction yield: actual yield

Answer 7

The amount of product that is actually obtained from a reaction

Question 8

% yield

Answer 8

% yield = actual yield x 100
theoretical yield

Question 9

Solution

Answer 9

Homogenous mixture of 2+ substances

Question 10

Solvent

Answer 10

Substance present in larger amount within solution

Question 11

Solute

Answer 11

Substance(s) present with smaller amounts dissolved in solvent

Question 12

Aqueous solution

Answer 12

Solution with water as solvent

Question 13

Solution concentration

Answer 13

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

Question 14

Molarity

Answer 14

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

Question 15

Dilute solution

Answer 15

Relatively small amount of dissolved solute

Question 16

Concentrated solution

Answer 16

Relatively large amount of dissolved solute

Question 17

Dilution

Answer 17

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

Question 18

Dilution formula

Answer 18

M₁V₁=M₂V₂

Where M = molarity
V = volume

*moles (n) of solute remain the same

Question 19

Solute and solvent interactions

Answer 19

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

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

Question 20

Charge distribution in water molecule

Answer 20

Oxygen = partial charge negative
Hydrogen = partial charge positive

Question 21

Hydration

Answer 21

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

Question 22

Electrolyte

Answer 22

Substance that, when dissolved in water, conducts electricity

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

Question 23

Nonelectrolyte

Answer 23

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

No cations, no anions
(Molecular substances)

Question 24

Strong electrolyte

Answer 24

Dissolve completely as ions

*Irreversible reaction.

Most salts, some acids and bases

Question 25

Weak electrolyte

Answer 25

Do **not** dissolve **completely** as ions \*Reversible reaction

Question 26

Dissociation

Answer 26

**Ions** of a **salt** separate as salt dissolves

Question 27

Ionization

Answer 27

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

Question 28

Soluble

Answer 28

A compound that dissolves in water

Question 29

Insoluble

Answer 29

A compound that does **not** dissolve in water

Question 30

Solubility

Answer 30

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

Question 31

Precipitation reactions & preciptate

Answer 31

Reactions that produce precipitate & An insoluble solid that separates from solution

Question 32

Spectator ions

Answer 32

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

Question 33

Complete ionic equation

Answer 33

Molecular equation's aqueous solutions are broken down to ions Solids, liquids, and gases are still written as compounds

Question 34

Net ionic equation

Answer 34

A complete ionic equation with spectator ions cancelled out A shorthand way of showing what ions react

Question 35

Gravimetric Analysis

Answer 35

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**

Question 36

Acid properties (6)

Answer 36

- sour taste - blue litmus paper --\> red (re**d** means aci**d**) - 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

Question 37

Base properties (5)

Answer 37

- bitter taste - feel slippery - red litmus --\> blue (**b**lue means **b**ase) - reacts with acids to produce salt and water (neutralization) - aqueous base solutions conduct electricity

Question 38

Arrhenius acid

Answer 38

Produces H⁺ (H₃O⁺) in water

Question 39

Arrhenius base

Answer 39

Produces OH^- in water

Question 40

H₃O⁺ Hydronium ion

Answer 40

Hydrated proton (i.e. H⁺ + H₂O) (Remember: H⁺ has 0 electrons, 0 neutrons, 1 proton)

Question 41

Brønsted acid

Answer 41

Proton **d**onor (**d**onor = aci**d**) Must contain *at least one* ionizable proton

Question 42

Brønsted base

Answer 42

Proton **a**cc**e**ptor (**a**cc**e**ptor = b**a**s**e**)

Question 43

Acid ionization

Answer 43

``` Acids = molecular compounds Ionization = ion formation in solution from compound + H<sub>2</sub>O 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

Question 44

Strong acids

Answer 44

Acids that ionize virtually 100% | (Irreversible)

Question 45

Weak acids

Answer 45

Ionize only a small percentage | (Reversible)

Question 46

Monoprotic acids

Answer 46

Each unit of acid yields *one* H⁺ ion

Question 47

Diprotic acids

Answer 47

Each unit of acid yields two H⁺​ ions

Question 48

Triprotic acids

Answer 48

Each unit of acid yields three H⁺​ ions

Question 49

Neutralization reactions

Answer 49

Acid + base --\> salt + water **Weak** acid + base --\> salt + water

Question 50

Gas-evolving reactions

Answer 50

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

Question 51

Compounds that undergo gas-evolution reactions (4)

Answer 51

Sulfides --\> H₂S (g) (Bi)carbonates --\> H₂CO₃ --\> CO₂ (g) (Bi)sulfi**t**es --\> H₂SO₄ --\> SO₂ (g) Ammonium --\> NH₄OH --\> NH₃ (g)

Question 52

Oxidation-reduction reactions | (Redox reactions)

Answer 52

Electron transfer reactions Uses chemical "bookkeeping" of election transfers

Question 53

Oxidation half-reaction

Answer 53

Shows the **loss** of electron(s) OIL = **o**xidiation **i**s **l**oss [of elections]

Question 54

Reduction half-reaction

Answer 54

Shows the gaining of electron(s) RIG = **r**eduction **i**s **g**aining [of electrons]

Question 55

Oxidation reaction

Answer 55

Half-reaction that involves **loss** of electron(s)

Question 56

Reduction reaction

Answer 56

Half-reaction that involves **gain** of electron(s)

Question 57

Oxidizing agents

Answer 57

Oxidiz**ing** agents are **reduced** and **gain** electron(s) RIG = reduction is gain --\> oxidizing agent reduces

Question 58

Reduction agents

Answer 58

**Reducing** agents are always **oxidized** and **lose** electron(s) OIL = oxidiz**ation** is loss -- reducing agents oxid**ize**

Question 59

Combination reaction

Answer 59

Type of redox reaction A + B --\> C

Question 60

Decomposition reaction

Answer 60

Type of redox reaction C --\> A + B

Question 61

Combustion reaction

Answer 61

Type of redox reaction A + O₂ --\> B Substance + O₂ --\> [1+ O-containing substances] + water Emits heat (exothermic)

Question 62

Displacement reaction

Answer 62

Type of redox reaction A + BC --\> AC + B 3 subtypes: * *Hydrogen** displacement * *Metal** displacement * *Halogen** displacement

Question 63

Activity series for halogens

Answer 63

F₂ \> Cl₂ \> Br₂ \> I₂ Note: order from top to bottom = decreasing activity Note: diatomic!

Question 64

Disproportionation reaction

Answer 64

Type of redox reaction Same element is *simultaneously* oxided *and* reduced

Question 65

Titrations

Answer 65

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

Question 66

Indicator

Answer 66

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

Question 67

Endpoint (equivalence point)

Answer 67

When an acid and base have become neutralized

Question 68

Modified dilution equation

Answer 68

M_acidV_acid(# of H⁺) = M_baseV_base(# of OH^-)