Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

chemistry > unit 9 - kinetics & equilibrium > Flashcards

unit 9 - kinetics & equilibrium Flashcards

(66 cards)

Start Studying
1
Q

a chemical equation describes

A

a chemical change (reaction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

kinetics

A

deals with the rates of chemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

rate

A

describe how fast a reaction takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

high rate

A

= fast (less time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

low rate

A

= slow (more time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

collision theory

A

For reactions to occur reactant particles must collide.

1) Spatial Orientation must be exact

2) Activation Energy must be met

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

more effective collisions: temperature

A

Increase in temperature increases reaction rates, due to more KE.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

more effective collisions: concentration

A

The greater the concentration (M) of reactants, the greater the reaction rates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

more effective collisions: nature of the reactants

A

Ionic substances react faster (dissociate) than covalent ones
(larger & contain more bonds).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

more effective collisions: surface area

A

Increase in surface area, increases the reaction rate because more
surfaces are exposed.
**powder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

more effective collisions: pressure

A

Increase in pressure on gases
increases reaction rates, because it
increases the concentration of the
particles.

**Little or no effect on solids & liquids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

more effective collisions: catalyst present

A

Increase the reaction rate by providing lowering the activation
energy & creates an alternate pathway.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

potential energy

A

is the energy stored within the bonds of reactants and products of a reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Heat Content (Heat of Reaction)

A

amount of heat absorbed or released in a chemical reaction

Heat of Reaction (ΔH = PEproducts – PEreactants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PED - Endothermic Reactions

A
  • Gain more energy than is released
  • Energy of the products is higher
    than the reactants
  • Energy is absorbed

● ΔH is + (positive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

PED - Exothermic Reactions

A
  • More energy is lost to the surroundings
  • Products have less energy than
    the reactants
  • Energy was released
  • ΔH is - (negative)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

∆H is the…

A

difference between the energy
needed to break the bonds in the reactants, and the energy given out when new bonds are formed in the products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ΔH is positive when the reaction is endothermic.

A

Heat of products are greater than reactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ΔH is negative when the reaction is exothermic.

A

Heat of reactants are greater than the products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Endothermic: heat is a…

A

reactant (on left side)

Ex. N2 + O2 + 182.6 KJ → 2NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Exothermic: heat is a…

A

product (on right side)

Ex. 2H2 +O2 → 2H2O + 486 KJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

(Δ H) is defined as the

A

difference in PE of the Products and the PE of the reactants

aka heat of reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Δ H is proportional To the AMOUNT of Material undergoing reaction.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Heat of Reaction & Surrounding Temperature: Exo Rxn

A

-Release Energy so the surrounding temperature (outside the reaction) gets warmed.

Ex. Heat Pack
Ex. From Table I the dissolving of NaOH (s), LiBr (s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Heat of Reaction & Surrounding Temperature: Endo Rxn
-Absorb Energy so the surrounding temperature (outside the reaction) gets colder Ex. A Cold Pack Ex: From Table I the dissolving of KNO3, NH3Cl, NH4NO3
26
Surface Temp: Exothermic
Reactions in which Heat is Released to the surroundings - Contents of test tube get Hotter -Surrounding Temperature INCREASES
27
Surface Temp: Endothermic
Reactions where Heat is Absorbed from the surroundings - Contents of test tube get Colder - Surrounding Temperature DECREASES
28
equilibrium
is the state of balance between 2 opposite reactions occuring at the same time - most reactions are reversible -><- must take place in a closed system
29
the state of equilibrium is...
dynamic = changing
30
equilibrium is reached when the reaction rates:
(Forward →) & (← Reverse) ARE EQUAL (are the same)
31
AT EQUILIBRIUM, concentration of reactants
≠ concentration of products - concentration of reactants and products are CONSTANT (staying the same)
32
point of equilibrium (balance) is affected by:
- Temperature Change (Δ T) - Change in [ ] Concentration - Change in Pressure (on gases)
33
reaction non-reversible
goes to completion
34
A Reaction is NON - REVERSABLE when:
1. a product is removed 2. a product is a gas & the gas escapes ex: NaHCO3 + HCl → NaCl + H2O + CO2 (g) 3. a product is a precipitate (insoluble) and can not react again **double replacement, table F 4. a product is H2O
35
types of physical equilibrium: phase equilibrium
Ex. H2O (s) → H2O (l) *If no Δ T* ← - At 0°C in a closed container, both water and ice exist at the same time. ** remember: melting point = freezing point Ex. H2O (l) → H2O (g) *If no Δ T* ← - At 100°C in a closed container, both liquid and gas exist at the same time.
36
phase equilibrium: in the open container
liquid evaporates until it is completely evaporated H2O (l) -> H2O (g)
37
in the closed container
evaporation continues but it is balanced by condensation H2O ( l ) → H2O (g) ←
38
types of physical equilibrium: solution equilibrium
dissolving NaCl (s) → NaCl (aq) ← recrystallization - rate dissolving = rate recrystall. - solution is saturated
39
Solubility
Mass of solute (solid) which can dissolve in a given amount of solvent.
40
equilibrium is reached when the
concentration of the reactants and products remain constant - the rate of the forward reaction equals the rate of the reverse reaction so there is no net change in the system
41
Le Chatelier's Principle
if a chemical system at equilibrium is disturbed it will change (SHIFT) in the direction to relieve the stress - the result is a new equilibrium at a diff point
42
how is stress applied
- change of concentration of reactants or products - change of temperature - change of pressure
43
equilibrium: increase in concentration
- if concentration of a substance increases, the reaction that reduces the substance is favored
44
equilibrium: increase in temperature
- temperature increase will shift a system in equilibrium to favor the endothermic reaction (to use up heat)
45
equilibrium: decrease in concentration
if concentration of a substance decreases, the reaction that increases that substance is favored
46
equilibrium: decrease in temperature
temperature decrease will shift a system in equilibrium to favor the exothermic reaction (replace the heat lost)
47
le chatelier's principle: PRESSURE
- pressure only effects the equilibrium of a system in which GASES are involved - pressure does not effect the equilibrium when there is no change in moles of gas
48
equilibrium: increase in pressure
an increase in pressure will favor the direction with fewer moles of gas
49
equilibrium: decrease in pressure
a decrease in pressure favors the direction with more moles of gas
50
le chatelier's principle: catalysts
- catalyst increase the rate of both the forward and reverse reactions equally - equilibrium is not disrupted and the concentration of reactants and products stay constant
51
common ion effect
ex: NaOH (s) ⟷ Na+ (aq) + OH- (aq) + 10.6 kcal - add KOH (adds OH-), amt NaOH (s) increases, Na+ decreases
52
entropy
a degree of randomness or disorder
53
More Organized → More Disorder
Solid to Liquid State Solid to Gas State Liquid to Gas State NI3 (g) → N2 (g) + 3 I2 (g) NaCl (s) → NaCl (aq)
54
Spontaneous Reactions:
A reaction that when initiated will continue without any outside influence.
54
Spontaneous Reactions are more favorable when:
1) Reactions are Exothermic- lower activation energy & Loss of energy (more stable state) 2) Increase in Entropy- Increase in Disorder
55
In nature systems usually move in the
exothermic and more disorder direction
56
what does nature prefer
- analogy: bedroom - low energy and high entropy
57
Law of Mass Action:
When a reversible reaction reaches equilibrium there is a mathematical relationship between the reactants and products.
58
what can Law Of Mass Action help predict
This can help us predict if the product or reactant concentrations would be greater at equilibrium or if they will be equal.
59
what is included in Keq equations
**Only concentration of gases and ions are included in the expression, OMIT solids & liquids.
60
what is Keq used to predict
Keq value is used to predict the concentration of products and reactants at equilibrium
61
Keq greater than 1
→ there are more products than reactants at equilibrium
62
Keq less than 1
there are more reactants than products at equilibrium
63
Keq = 1
[Products] = [ Reactants] at equilibrium
64
when there is a decrease in volume, the equilibrium will shift to favor the
direction that produces fewer moles of gas
65
when there is an increase in volume, the equilibrium will shift to favor the
direction that produces more moles of gas

chemistry (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions