question of the day for a reaction involving a single reactant, the following data were obtained....
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Question of the Day
For a reaction involving a single reactant, the following data were obtained.
Day 2 4-15
Determine the order of the reaction. Either show work or explain!
Question of the Day
Does an oreo get soggy quicker in milk or a milkshake? Explain the difference in reaction rate in terms of one of the four factors influencing reaction rates (BE SPECIFIC!)
Day 3 4-16
http://wps.prenhall.com/esm_brown_chemistry_9/2/660/169060.cw/index.html
Homework # 2 Chapter 14 – w/ discussion partner – show me successful screen (100%)
# 7 = the reaction rate would quadruple. doubling the partial pressure is the same as doubling the concentration.
Question of the DayThe following data were collected for the rate of disappearance
of NO in the reaction: 2NO(g) + O2(g) 2NO2(g)
Write the rate law for this equation: _______________________
Solve for k:
What are the units for k?
Day 5 4-22
Rxn Mechanisms & Rate-Determining StepsA. A reaction mechanism is a series of ____________ that lead to a net reaction.
B. Reaction mechanisms can have _____________ steps.
C. Parts of mechanisms
1. Net reaction is _________
simple rxns
one or more
the goal
Rxn Mechanisms & Rate-Determining StepsC. Parts of mechanisms
1. Net reaction is __________
2. Elementary step is one of the __________ in the ________
3. Intermediate product is a product that is made by _______________ _____ that becomes a _________ in a subsequent ________________
the goal
reactions process
an elementarystep reactan
telementary step
Rxn Mechanisms & Rate-Determining StepsC. Parts of mechanisms
4. Catalyst is a substance that first appears as a _________ in one ________________ and then becomes a ________ in a subsequent ________________
reactantelementary stepproductelementary step
Reaction mechanisms that have multiple steps have one step that is the rate-determining step. The rate-determining step is the step that is the _______ of all the steps.
Rxn Mechanisms & Rate-Determining Steps
slowest
E. Write several mechanisms and identify any intermediates and catalysts.
1. 1-step mechanism for reaction of calcium oxide with water
Rxn Mechanisms & Rate-Determining Steps
Question of the DayDay 6 4-23
Describe how intermediates, activated complexes, and catalysts are different (thoroughly!).
http://wps.prenhall.com/esm_brown_chemistry_9/2/660/169060.cw/index.html
Homework # 2 Chapter 14 – w/ discussion partner – show me successful screen (100%)
# 7 = the reaction rate would quadruple. doubling the partial pressure is the same as doubling the concentration.
E. Write several mechanisms and identify any intermediates and catalysts.
2. 2-step mechanism for rxn of NO2 with CO to produce NO and CO2 (all gases)
Rxn Mechanisms & Rate-Determining Steps
NO2 + NO2 NO3 + NO
NO3 + CO NO2 + CO2
slow
fast
NO2 + CO NO + CO2 net
Period 1 stopped
4-22
2. 2-step mechanism for rxn of NO2 with CO to produce NO and CO2 (all gases)
Rxn Mechanisms & Rate-Determining Steps
NO2 + NO2 NO3 + NO
NO3 + CO NO2 + CO2
slow
fast
NO2 + CO NO + CO2 net
Intermediate =NO3
E. Write several mechanisms and identify any intermediates and catalysts.
3. 3-step mechanism for the rxn of HBr with O2 to produce H2O and Br2 (all gases)
Rxn Mechanisms & Rate-Determining Steps
HBr + O2 HOOBr
HBr + HOOBr 2 HOBr
2 HBr + 2 HOBr 2 H2O + 2 Br24 HBr + O2 2 H2O + 2 Br2
3. 3-step mechanism for the rxn of HBr with O2 to produce H2O and Br2 (all gases)
Rxn Mechanisms & Rate-Determining Steps
HBr + O2 HOOBr
HBr + HOOBr 2 HOBr
2 HBr + 2 HOBr 2 H2O + 2 Br24 HBr + O2 2 H2O + 2 Br2
Intermediates =HOOBr and HOBr
4. Write the net rxn for the following 2-step mechanism.
NO2(g) + SO2(g) → NO(g) + SO3(g)
2 NO(g) + O2(g) → 2 NO2(g)
Rxn Mechanisms & Rate-Determining Steps
ReviewAnalyze the following reaction mechanism:
step 1: N2O N2 + Ostep 2: N2O + O N2 + O2
What is the net reaction?
Are there any intermediates and/or catalysts present?
Equilibrium Equilibrium occurs when the forward and
reverse reactions occur at equal rates – NOT a standstill!
Equilibrium
A. Physical Equilibrium Example
1. H2O(l) ⇄ H2O(g)
2. Appearance of system
Rate of Evap. = Rate of Cond.Rate of Evap. = Rate of Cond.
To regular eyes: To regular eyes: Looks as if nothing is Looks as if nothing is happeninghappening
But on the molecular level: But on the molecular level: 2 rxns or 2 rxns or s occur s occur simultaneouslysimultaneously
B. Chemical Reaction Options
1. Rxn goes to completion products stay & reaction stops; Ex : burning 2. No go : He + Ne no rxn3. Rxn reaches equilibrium = get a set
amount of reactants & products coexisting
C. Main Concern of Equilibrium Calculations
1. How FAR will the reaction go?2. How much product can be made?
Equilibrium
D. What conditions must be met to attain equilibrium?
– Constant T & P– Closed container– G = 0
Equilibrium
E. Example equilibrium system and experimental data: 2 HI(g) I⇄ 2(g) + H2(g)
[HI] [I2] [H2] → [HI] [I2] [H2]
Exp #1 0.2 0 0 →
Exp #2 0 0.1 0.1 →
Exp #3 0.1 0.1 0.1 →
0.160.16 0.020.02 0.020.02
0.160.16 0.020.02 0.020.02
0.240.24 0.030.03 0.030.03
Equilibrium
• What happened to the concentrations of each substance during the experiments?
– Exp #1 & #2 •Changed to form chemicals not
present at the start of the reaction
– Exp #3•Changed to form more of the “favored” chemicals
Equilibrium
C. Example of system reaching equilibrium
N2O4(g) ⇄ 2 NO2(g) at 100 °C
Time (s) 0 20 40 60 80 100
[N2O4] 0.100 0.070 0.050 0.040 0.040 0.040
[NO2] 0.000 0.060 0.100 0.120 0.120 0.120
Equilibrium
http://chemconnections.org/Java/equilibrium/index.html
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/animations/equilvpBr2V8.html
Equilibrium
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