Search found 60 matches
- Sat Mar 09, 2019 6:14 pm
- Forum: Van't Hoff Equation
- Topic: pH and van’t hoff
- Replies: 6
- Views: 1396
Re: pH and van’t hoff
With a temperature change, the K changes, so then the pH would also change because the concentration of H+ changes.
- Sat Mar 09, 2019 6:11 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step
- Replies: 2
- Views: 268
Re: Slow step
The slow step is the one with the slowest rate, k. The reaction can only be as fast as the slowest step, so the reaction rate becomes that of the slowest step.
- Fri Mar 08, 2019 4:56 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Test 2
- Replies: 6
- Views: 1801
Re: Test 2
For the snowflakes, delta H is negative because the snowflakes lose heat, and delta S is negative because going from a liquid to a solid is less chaotic. Negative delta H minus a negative delta S makes a negative delta G. For the sublimation, delta H is positive because heat is going in, and delta S...
- Sun Mar 03, 2019 2:22 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E° is 0 for Concentration Cells
- Replies: 3
- Views: 381
Re: E° is 0 for Concentration Cells
In concentration cells, it is the same metal being reduced and oxidized so when you subtract the E of the anode from the E of the cathode, you will get 0.
- Sun Mar 03, 2019 2:21 pm
- Forum: Van't Hoff Equation
- Topic: K value- Temp
- Replies: 6
- Views: 986
Re: K value- Temp
Using leChatelier's principle, when the temperature is changed, depending on whether the reaction is endothermic or exothermic, the reaction will favor either the reactants or the products. We use the equation -deltaH/R(1/T2 - 1/T1) = ln(K2/K1) to find what the new K is when the temperature is chang...
- Sun Mar 03, 2019 2:18 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 4
- Views: 391
Re: Nernst Equation
In the Nernst equation, there are the constants R and F which should be given. Temperature is usually 298K. You can find n using the standard reduction potentials and K can be found with the concentrations or partial pressures. Ecell can also be found using standard reduction potentials.
- Mon Feb 25, 2019 6:54 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Question 9.65 (Sixth Edition)
- Replies: 1
- Views: 309
Re: Question 9.65 (Sixth Edition)
You calculate the delta S for each reaction of formation, because if delta S is more negative, then delta G will be more positive. If you look at the equation for Gibbs Free Energy: delta G = delta H - T delta S, the delta S will need to be more negative to make delta G positive. If delta G is posit...
- Mon Feb 25, 2019 6:48 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Tips for Discussion Test
- Replies: 6
- Views: 548
Re: Tips for Discussion Test
I have found it helpful to create my own outline of what we have learned based on the lecture notes, and reinforcing it with the relevant chapters in the textbook and Dr Lavelle's outlines.
- Thu Feb 21, 2019 9:03 am
- Forum: Balancing Redox Reactions
- Topic: Weekly Homework
- Replies: 3
- Views: 380
Re: Weekly Homework
You should ask your TA what homework problems they want, and in general, you should usually follow what we are learning in class.
- Wed Feb 20, 2019 10:14 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta H
- Replies: 5
- Views: 580
Re: Delta H
There is a chart in the 7th edition pg. 330 that I found helpful for this. It's table 4J.1. I can write it here also: Delta H Delta S Spontaneous? negative positive yes, delta G < 0 negative positive yes, if TdeltaS < deltaH and deltaG < 0 positive positive yes, if TdeltaS > deltaH and deltaG < 0 po...
- Wed Feb 20, 2019 10:06 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Midterm Question
- Replies: 5
- Views: 840
Re: Midterm Question
K is the [P]/[R] so if K is very large, the [P]>[R]. Because the concentration of products is greater at equilibrium, the products must be more stable, because the reaction favors them.
- Wed Feb 20, 2019 10:03 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Midterm Question (#3.D)
- Replies: 2
- Views: 462
Re: Midterm Question (#3.D)
The reaction is with a polyprotic acid, so it can donate more than one proton, so there will be more than one reaction. They are asking for the second reaction, so you must first write the reaction with the first proton donated, then write the reaction with the second proton donated.
- Tue Feb 12, 2019 5:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: units
- Replies: 2
- Views: 342
Re: units
The units of q, delta U, and delta H depend on the other units in the problem, but they will always be in either J or kJ.
- Tue Feb 12, 2019 4:59 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Problem 4F.11 7th Edition
- Replies: 2
- Views: 249
Problem 4F.11 7th Edition
Problem 4F.11 asks you to find the change in entropy when the volume changes from 3L to 0.5L and the temperature changes from 291.5K to 301.1K. When calculating delta S for the temperature change, the solutions used delta S = nRln(T2/T1). Why didn't they use delta S = nCln(T2/T1)?
- Tue Feb 12, 2019 4:54 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Test 1 Question
- Replies: 3
- Views: 377
Re: Test 1 Question
If delta H is positive that means that the reaction is endothermic. In an endothermic reaction, if the temperature is increased the reaction will favor the forward reaction.
- Mon Feb 04, 2019 8:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: HW question
- Replies: 1
- Views: 248
Re: HW question
Work is being done by the system against the atmosphere, so work should be positive.
- Mon Feb 04, 2019 8:00 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Thermodynamic equations
- Replies: 1
- Views: 289
Re: Thermodynamic equations
The heat capacity equation varies depending on whether there is constant pressure or constant volume. You use q=nCT, but for constant pressure, C=(5/2)R, and for constant volume, C=(3/2)R. W = - P x ∆V is used to find work, which is then used in the equation ∆U = q + w. For ∆U = q + w, if volume is ...
- Mon Feb 04, 2019 7:47 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Important Thermochemistry Equations
- Replies: 3
- Views: 405
Re: Important Thermochemistry Equations
Going off of the equation sheet on the website, we should know:
Ideal gas, Cp = (5/2) R
Ideal gas, Cv = (3/2) R
Ideal gas, U = 3/2 nRT
∆U = q + w
q = n C ∆T
W = - P x ∆V
PV = nRT
w= -nRTln(V2/V1)
Those are all of the Thermochemistry equations that I could find on the sheet.
Ideal gas, Cp = (5/2) R
Ideal gas, Cv = (3/2) R
Ideal gas, U = 3/2 nRT
∆U = q + w
q = n C ∆T
W = - P x ∆V
PV = nRT
w= -nRTln(V2/V1)
Those are all of the Thermochemistry equations that I could find on the sheet.
- Fri Feb 01, 2019 2:40 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Analogy of Boulder
- Replies: 5
- Views: 999
Re: Analogy of Boulder
He was saying that a boulder could just roll down the hill on its own, so it wouldn't require work to roll down the hill. But, the boulder will not roll up the hill on its own, so it will require work to be pushed up the hill.
- Fri Feb 01, 2019 9:48 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4B13 7th edition
- Replies: 1
- Views: 236
Re: 4B13 7th edition
Look at the units of the two constants and see which one will give you the units of what you are solving for.
- Fri Feb 01, 2019 9:46 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Cvm and Cpm ?
- Replies: 2
- Views: 3363
Re: Cvm and Cpm ?
Cv is used when there is constant volume and Cp is used when there is constant pressure.
- Sun Jan 27, 2019 3:53 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4C.1- molar heat capacity (7th edition)
- Replies: 1
- Views: 164
Re: 4C.1- molar heat capacity (7th edition)
The book states that the molar heat capacity increases with molecular complexity. The molar heat capacity of nonlinear molecules is higher than linear molecules because nonlinear molecules can rotate about three axes, not just two axes. I don't think we have gone over this in class yet.
- Sun Jan 27, 2019 3:49 pm
- Forum: Phase Changes & Related Calculations
- Topic: Lecture 1/25
- Replies: 1
- Views: 264
Re: Lecture 1/25
He talked about how the third method to solve for enthalpy is to use standard enthalpies of formation. You take the standard enthalpies of formation of all the reactants and subtract them from all the standard enthalpies of formation of all the products. This can be used to solve for the standard re...
- Sun Jan 27, 2019 3:46 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 3 Methods to solve for Enthaply
- Replies: 3
- Views: 409
Re: 3 Methods to solve for Enthaply
The first method is to use multiple chemical reactions and add them together to find the enthalpy of a certain reaction. The second method is to use bond enthalpies adding the bonds broken with the bonds formed. This method is the most accurate for diatomic molecules, and the rest are averages, so t...
- Wed Jan 16, 2019 8:51 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 7th Edition 6B.9
- Replies: 1
- Views: 196
7th Edition 6B.9
For parts (i) and (ii) of the problem, we are given the [H30+] = 1.50M and [OH-] = 1.50M respectively. When I calculated the pH and pOH, I found that the answer was -0.176. When we know that taking the log of the concentration will give us a positive answer, do we just not put a negative sign in fro...
- Tue Jan 15, 2019 4:16 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic vs. Endothermic Reaction
- Replies: 9
- Views: 3167
Exothermic vs. Endothermic Reaction
How do we know if a reaction is endothermic or exothermic? Can we only know if we are given delta H?
- Mon Jan 14, 2019 10:26 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pH question
- Replies: 3
- Views: 292
Re: pH question
You need to use the formula M1V1=M2V2 because the volume of the container was changed. You have the original volume and concentration, and the new volume, so you must solve for the new concentration.
- Mon Jan 14, 2019 3:45 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 7th Edition 5J.13
- Replies: 1
- Views: 184
7th Edition 5J.13
Question 5J.13 asks if there will be more ammonia will be formed if an equilibrium mixture containing 2.23 mmol N2 and 6.69 mmol H2 in a 500. mL container is increased in temperature from 600. K to 700. K. K=1.7x10^-3 at 600. K and K=7.8x10^-5 at 700.K. How does this problem relate to LeChatelier's ...
- Mon Jan 14, 2019 3:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I.23 7th Edition
- Replies: 1
- Views: 223
Re: 5I.23 7th Edition
In the solutions, they are using moles instead on molarity in the ICE table. They then convert to molarity after they have done the ICE table.
- Mon Jan 14, 2019 2:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th edition 5I.13 Part C
- Replies: 1
- Views: 183
7th edition 5I.13 Part C
Question 5I.13 Part C asks whether the Cl2->2Cl or F2->2F reaction is more thermodynamically stable. How do we know which is more stable?
- Sat Dec 08, 2018 10:40 pm
- Forum: Amphoteric Compounds
- Topic: water
- Replies: 4
- Views: 501
Re: water
The double arrows represent equilibrium reactions.
- Sat Dec 08, 2018 10:37 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Hydrogen Bonding
- Replies: 5
- Views: 710
Re: Hydrogen Bonding
In hydrogen bonding, the N, O, and F on one molecule form a bond with the H on another molecule, so there needs to be an H bonded to N, O, or F for the molecule to have hydrogen bonding IMF's. For example, in a molecule with an O-H bond, it is polar, so when another O-H bond nearby will have its H t...
- Sat Dec 08, 2018 10:32 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: H Bonds stronger than dipole-dipole
- Replies: 2
- Views: 11448
Re: H Bonds stronger than dipole-dipole
A hydrogen bond is about 10% of the typical covalent bond strength, making it a much stronger attractive force than dipole-dipole and london dispersion.
- Sun Dec 02, 2018 9:38 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Drawing Chelates
- Replies: 1
- Views: 228
Re: Drawing Chelates
You would draw the normal shape of the ligand that is a chelate, and then the lone pairs would bond to the central metal atom, forming a ring.
- Sun Dec 02, 2018 9:29 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: HW 7th edition 6B.9
- Replies: 3
- Views: 345
HW 7th edition 6B.9
For 6B.9 part a row i and ii, we are given a chart giving just the [H3O+] for i and [OH-] for ii and we have to find the pH, pOH, [H3O+], and [OH-]. For i, we are given [H3O+] = 1.50M. If we use the formula pH = -log[H3O+], then we get a negative pH, and the same goes for using pOH = -log[OH-] in ii...
- Sun Dec 02, 2018 9:21 pm
- Forum: Amphoteric Compounds
- Topic: HW 7th edition 6A.17
- Replies: 1
- Views: 183
HW 7th edition 6A.17
Can someone please explain c and d of 6A.17? It says to state whether As2O3 and Bi2O3 are acidic, basic, or amphoteric. Why are they amphoteric?
- Sat Nov 24, 2018 3:33 pm
- Forum: Hybridization
- Topic: Specific steps for 2.45 7th Ed.
- Replies: 1
- Views: 84
Re: Specific steps for 2.45 7th Ed.
For part a, there are three trigonal planar shapes connected by each carbon atom. For part b, you must look at the hybridization of each atom to determine what kind of bond is used. For the C-H bonds, C is 2sp2 hybridized and H is just a 1s orbital, so it is a sigma bond. For the C=C bond, both C's ...
- Sat Nov 24, 2018 3:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shape of BF3
- Replies: 1
- Views: 374
Re: Shape of BF3
If you look at the valence electrons of B and F, Boron has 3 valence electrons and Fluorine has 3(7) valence electrons, totaling 24 total electrons to use in your lewis structure. If you use 6 electrons for B-F bonds, then you have 18 left over. F won't be stable unless it has a complete octet, so y...
- Sat Nov 24, 2018 1:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Slightly less than bond angles
- Replies: 4
- Views: 437
Re: Slightly less than bond angles
You would just say slightly less than what the normal bond angle is.
- Sat Nov 17, 2018 9:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining a Dipole Moment
- Replies: 2
- Views: 314
Determining a Dipole Moment
I am confused on what is used to determine whether an atom is positively or negatively charged in a dipole moment. Is it related to formal charge?
- Sat Nov 17, 2018 9:36 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi bonds
- Replies: 2
- Views: 190
Re: Sigma and Pi bonds
Pi bonds do not allow atoms to rotate as well. If the atoms rotate, the pi bonds will easily break. However, sigma bonds do allow the atoms to rotate.
- Sat Nov 17, 2018 9:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Shapes
- Replies: 4
- Views: 504
Re: VSEPR Shapes
An atom is trigonal pyramidal if it has four areas of electron density but only has three bonding electron pairs, or AX3E. An atom is t-shape if it has five areas of electron density but only has four bonding electron pairs, or AX3E2.
- Sun Nov 11, 2018 2:56 pm
- Forum: Lewis Structures
- Topic: Formal charges
- Replies: 15
- Views: 1219
Re: Formal charges
If we disregard the formal charges when drawing our lewis structure will it be wrong? It could possibly be wrong if there is a better lewis structure that will give the most atoms a formal charge of zero, or if an atom that is not as electronegative as another has a negative formal charge. It would...
- Sun Nov 11, 2018 2:53 pm
- Forum: SI Units, Unit Conversions
- Topic: Bond length
- Replies: 3
- Views: 710
Re: Bond length
Bond length also affects the dissociation energy, or the energy required to break a bond. Single bonds require less energy to break than double or triple bonds.
- Sun Nov 11, 2018 2:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molecular shapes
- Replies: 13
- Views: 922
Re: molecular shapes
We will probably be going more in depth and learning more this week.
- Sun Nov 04, 2018 11:43 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty principle question
- Replies: 2
- Views: 472
Re: Uncertainty principle question
The uncertainty would be twice the value of the difference in speed, so it would be 0.8 m/s.
- Sun Nov 04, 2018 11:39 am
- Forum: Ionic & Covalent Bonds
- Topic: Chemical Bonds
- Replies: 5
- Views: 540
Re: Chemical Bonds
Typically, when the electronegativity difference between the two atoms is greater than 2, an ionic bond forms. If the electronegativity difference is less than 1.5, it is a covalent bond. However, all ionic bonds have some covalent character.
- Sun Nov 04, 2018 11:34 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Drawing orbitals
- Replies: 4
- Views: 1646
Re: Drawing orbitals
The p orbitals have a shape with two lobes, and depending on whether it is px, py, or pz, you would draw the two lobes on the x axis for px, the y axis for py, and the z axis for pz.
- Sat Oct 27, 2018 6:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lowest Energy
- Replies: 4
- Views: 328
Re: Lowest Energy
Lowest energy does not have to do with ground state. Lowest energy is when all of the electrons are most stable, so when the octet of valence electrons is filled. This is only ground state for noble gases.
- Sat Oct 27, 2018 6:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: ionization energy [ENDORSED]
- Replies: 4
- Views: 213
Re: ionization energy [ENDORSED]
The further away an electron is away from the nucleus, the easier it is to remove. Once the electron that is furthest away from the nucleus is removed, the next farthest would be removed. However, this electron is closer to the atom than the first electron, making it harder to remove, and increasing...
- Sat Oct 27, 2018 6:28 pm
- Forum: Lewis Structures
- Topic: Electron Configuration
- Replies: 4
- Views: 466
Re: Electron Configuration
S, p, d, and f orbitals all have an angular momentum number (l) associated with it.
For s, l=0
For p, l=1
For d, l=2
For f, l=3
And so on. The l is a subshell, so each energy level (n) has different subshells that are allowed, giving you the s, p, d, and f orbitals.
For s, l=0
For p, l=1
For d, l=2
For f, l=3
And so on. The l is a subshell, so each energy level (n) has different subshells that are allowed, giving you the s, p, d, and f orbitals.
- Sat Oct 20, 2018 5:48 pm
- Forum: Properties of Light
- Topic: Wavelengths and frequencies
- Replies: 10
- Views: 644
Re: Wavelengths and frequencies
I don't think we need to know specific wavelengths, but we do have to know the order from longest to shortest wavelengths.
- Sat Oct 20, 2018 5:40 pm
- Forum: Properties of Light
- Topic: Homework question
- Replies: 1
- Views: 147
Re: Homework question
You must calculate the threshold energy of the photon using the equation: E=h(frequency). They give you the frequency and h is a constant, therefore you can calculate the threshold energy of the photon.
- Sat Oct 20, 2018 5:37 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Symmetric vs. Non symmetric orbitals
- Replies: 4
- Views: 1402
Re: Symmetric vs. Non symmetric orbitals
S-orbitals do not have nodal planes, so they have even electron density distribution, making the shell symmetric. Every other orbital has at least one nodal plane, meaning there is zero electron density distribution and making the shell not symmetric. This explains why the p-orbitals have a dumbbell...
- Sun Oct 14, 2018 1:33 pm
- Forum: Properties of Electrons
- Topic: Quantum World 1.43
- Replies: 2
- Views: 316
Re: Quantum World 1.43
The Heisenberg Equation is (delta p, the uncertainty of momentum) times (delta x, the uncertainty of position) is greater than or equal to 0.5 times h/2pi.
- Sun Oct 14, 2018 1:29 pm
- Forum: Photoelectric Effect
- Topic: Threshold energy [ENDORSED]
- Replies: 17
- Views: 2090
Re: Threshold energy [ENDORSED]
When I went to a workshop the UA described the energy in the light like a glass of water. In the glass, the water is the energy needed to remove an electron, the threshold energy. The extra volume of the glass above the water is the kinetic energy that is given to the electron.
- Sun Oct 14, 2018 1:18 pm
- Forum: Properties of Electrons
- Topic: Photoelectric Experiment
- Replies: 9
- Views: 516
Re: Photoelectric Experiment
The energy of the photon must be greater than or equal to the energy to remove an electron. Light sources with long wavelengths have a lower frequency. The lower frequency does not have enough energy to remove an electron, even if it has high intensity. Intensity is also the amplitude of the wave. T...
- Sat Oct 06, 2018 7:56 pm
- Forum: Empirical & Molecular Formulas
- Topic: homework problem F9
- Replies: 3
- Views: 257
Re: homework problem F9
You divide the percentages by the molar mass of each element. For example, divide 63.15g C by 12.01 g/mol.
- Sat Oct 06, 2018 5:26 pm
- Forum: Empirical & Molecular Formulas
- Topic: Chem Mod Empirical and Molecular Formulas Problem 22
- Replies: 1
- Views: 113
Chem Mod Empirical and Molecular Formulas Problem 22
I did the chem module for empirical and molecular formulas and I was having trouble on problem 19. I calculated the moles of each element: for C I got 3.283 moles, for O I got 3.286 moles, and for H I got 7.802 moles. So, I got a ratio of 1:1:2.38. I figured I would multiply by 3 to get 3:3:7, but t...
- Sat Oct 06, 2018 4:49 pm
- Forum: Limiting Reactant Calculations
- Topic: Chem Mod Limiting Reactants
- Replies: 2
- Views: 266
Chem Mod Limiting Reactants
I did the module for limiting reactants, and I kept getting confused on problems 30, 32, and 33. These were the problems with the formula 2A + 1B --> 3C. For 30, the question is If you have 1 mole A and 1 mole B, which is the limiting reactant? Wouldn't B be the limiting reactant because there are l...