## Search found 62 matches

Tue Mar 13, 2018 6:00 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 1
Views: 176

### Re: Arrhenius Equation

In case you are wondering, ln(k) = ln(A) - (Ea/RT) is just another way of writing the original Arrhenius equation in the exponential form (we just took the natural log of both sides to get this new equation). Since generally we use experimental data in the form of a graph to determine E a , we usual...
Tue Mar 13, 2018 5:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.89
Replies: 2
Views: 193

### Re: 15.89

There would have to be more information give to you. You cannot make an assumption or an estimate based solely off the information they give you in the problem. Therefore, when you draw the graph, the E a for either Step 1 or Step 3 can be higher, but there just isn't enough to make a judgement abou...
Tue Mar 13, 2018 5:51 pm
Forum: First Order Reactions
Topic: 15.85
Replies: 3
Views: 316

### Re: 15.85

You're going to draw what the transition state will look like. Basically, it'll look like a variation/combination of whatever the reactant molecules they give you are. All the bonds in the transition states are draw with dotted/dashed lines instead of solid lines because we are representing these bo...
Mon Mar 05, 2018 3:59 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Q8
Replies: 2
Views: 212

### Re: Test 2 Q8

You have to balance the half reactions to get an overall redox reaction. In this case, the half reactions are already balanced, so the reaction is AgCl(s) + I-(aq) -> Cl-(aq) + AgI(s). So I- is a reactant and Cl- is a product, and Q = [Cl-]/[I-] (remember that solids are not included in this reactio...
Mon Mar 05, 2018 3:54 pm
Forum: Calculating Work of Expansion
Topic: Calculating Work
Replies: 1
Views: 151

### Re: Calculating Work

w = -PextΔV (the sign if negative because this is the work that the system is doing)
Mon Mar 05, 2018 3:52 pm
Forum: Zero Order Reactions
Topic: Catalysts in Zero Order Reactions
Replies: 1
Views: 275

### Re: Catalysts in Zero Order Reactions

Basically, catalysts can turn some reactions into zero order reactions because of their very nature to facilitate collisions. A reaction that is second order, such as the decomposition of NO 2 to N 2 and O 2 , can be turned into a zero order reaction in the presence of a hot platinum wire (which act...
Mon Feb 26, 2018 10:19 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.47
Replies: 3
Views: 250

### Re: 14.47

I think that's the right answer. The book might just have the wrong answer. If you follow all the steps in the solutions manual, you should end up with e15 = 3269017, not 106
Mon Feb 26, 2018 10:00 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Graphs in Lecture
Replies: 2
Views: 212

### Re: Graphs in Lecture

I can't exactly remember what the curved graph was for, but I can take a guess. The linear graph depicted a first order reaction, where the natural log of the concentration of A (ln[A]) was plotted against time. This was called the integrated rate law for the first order reaction. Since the integrat...
Mon Feb 26, 2018 9:47 pm
Forum: General Rate Laws
Topic: Confusion about the Rate Laws
Replies: 1
Views: 132

### Re: Confusion about the Rate Laws

A differential rate law is just an equation that shows what happens when you have a certain concentration of reactants (rate vs. concentration), and it has the form Rate = (1/a)(d[A]/dt) for a reaction A --> P (Get it? Since it's a differential equation, we are concerned with the rate of the reactio...
Wed Feb 21, 2018 5:34 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.41
Replies: 1
Views: 149

### Re: 14.41

This is an example of a concentration cell. Since the only thing changing in this reaction is the concentration of H + , the "equation" is: H + (10 -3 M) --> H + (10 -4 M) There is only e- being transferred per mole equivalent of this reaction. If you wanted to do the half reactions, you w...
Wed Feb 21, 2018 5:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.43
Replies: 1
Views: 147

### Re: 14.43

Since a cell only works if the overall cell potential is positive, we use this info to figure which of the two electrodes are the anode and which is the cathode. Since tin has a lower cell potential than hydrogen (hydrogen has the abbreviation for S. H. E. in the manual, standing for Standard Hydrog...
Wed Feb 21, 2018 4:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13 Part D
Replies: 2
Views: 290

### Re: 14.13 Part D

In this equation, some of the Au+ is being oxidized to Au3+ and some of it is being reduced to Au. You set up the half reactions similarly, with Au+ taking part in both half reactions: Reduced: Au + + e - --> Au Oxidized: Au + --> Au 3+ + 2e - Balancing the equation yields 3Au + --> 2Au + Au 3+ I'm ...
Tue Feb 13, 2018 8:55 pm
Forum: Calculating Work of Expansion
Topic: w in a calorimeter
Replies: 2
Views: 234

### Re: w in a calorimeter

In a constant volume calorimeter, there is 0 work done since there is no volume change. For constant pressure calorimeters, there is work done by the system. This is because expansion/contraction can be done against a constant pressure. In constant volume calorimeter, q = ΔU since no work can be don...
Tue Feb 13, 2018 8:29 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Relationship between free energy and work
Replies: 2
Views: 215

### Re: Relationship between free energy and work

Gibbs Free Energy is the amount of energy that is available to do work. A reaction that has a negative free energy value means that it can do work, whereas a positive free energy value means that a system needs to have work done to it. In the context of chemical reactions, negative values indicate t...
Tue Feb 13, 2018 8:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q and change in T
Replies: 1
Views: 170

### Re: q and change in T

Yup you can assume that, unless there's a specific condition stating that temperature is constant, such as when a system is isothermal (meaning that the heat that is inputted is cancelled out by the system doing work so that there is no temperature change).
Tue Feb 06, 2018 8:41 pm
Forum: Balancing Redox Reactions
Topic: Solutions in beakers
Replies: 2
Views: 188

### Re: Solutions in beakers

Each beaker has a solution of respective ions for each electrode metal. So in a beaker with a zinc electrode, the solution it is in will contain Zn 2+ ions. If it is a copper electrode, the solution contains copper ions. Of course you can't usually get pure metal ions on their own; they had to have ...
Tue Feb 06, 2018 8:34 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: How to approach 9.19
Replies: 2
Views: 207

### Re: How to approach 9.19

Since entropy is a state function (doesn't matter how we get to the final state), we can take a rather strange approach to get to the answer. We need to have 3 steps in our process: 1) heat the liquid water from 85°C to 100°C, 2) vaporize the water, 3) cool the water vapor from 100°C to 85°C. Theref...
Tue Feb 06, 2018 8:25 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.13
Replies: 6
Views: 380

### Re: 9.13

The answer key doesn't use C of any kind... Are you perhaps looking at the wrong problem?
Tue Feb 06, 2018 8:02 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard State
Replies: 5
Views: 299

### Re: Standard State

That is essentially what we would do, but it is more likely that we have to factor in phase changes rather than pressure changes (since we just have to look up values for phase change enthalpies). For the most common elements/molecules, you should probably know what their standard states are at 298K...
Tue Feb 06, 2018 7:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 7
Views: 413

### Re: Salt Bridge

It might not be included in a diagram that's provided to you. Basically, a salt bridge just helps to keep electrons flowing throughout the cell. Without a salt bridge, the electrons would flow from anode to cathode and would build up in the cathode portion. Eventually, since all the electrons are al...
Tue Feb 06, 2018 7:48 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.33
Replies: 1
Views: 120

### Re: 9.33

The product molecules that are formed are in the "liquid" phase (it is an aqueous solution). Since we are going from gases, which have high entropy since they can occupy many different microstates/positions, to liquids, which can occupy fewer microstates, the entropy is decreasing.
Mon Jan 29, 2018 7:40 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Calculating change in entropy for a process? (9.3)
Replies: 2
Views: 171

### Re: Calculating change in entropy for a process? (9.3)

It's just an explanation for how to calculate entropy for certain reactions. We don't worry about whether a reaction can only go in one way or another. This allows us to do things like find the entropy for reactions that are not necessarily common. Again, it has to do with the fact that entropy is a...
Mon Jan 29, 2018 7:35 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.13
Replies: 3
Views: 210

### Re: 9.13

I believe the solutions manual says that you just assume 1 mole of nitrogen gas (it's not mentioned anywhere in the problem).
Mon Jan 29, 2018 7:33 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: What is the relationship between reversibility and spontaneity of a reaction?
Replies: 3
Views: 288

### Re: What is the relationship between reversibility and spontaneity of a reaction?

If a reaction is spontaneous at a certain temperature, its reverse reaction is probably nonspontaneous at the same temperature, but this is more of a general statement than an actual rule or relationship.
Wed Jan 24, 2018 2:00 pm
Forum: Calculating Work of Expansion
Topic: 8.3
Replies: 3
Views: 234

### Re: 8.3

Since w = P(deltaV) usually works in the units of Pascals for pressure and m 3 for volume, we need a conversion factor to account for the fact that the pressure given in the problem is in atmospheres. This is done in one of two ways. 1) convert atm to pascals (101325 pascals = 1 atm), convert cm 3 t...
Mon Jan 22, 2018 5:48 pm
Forum: Phase Changes & Related Calculations
Topic: Tempt and phase change
Replies: 1
Views: 121

### Re: Tempt and phase change

You have to look up enthalpies for liquid water versus ice (solid water), and do the following:

deltaHliquid - deltaHsolid = deltaHfusion
Mon Jan 22, 2018 5:46 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity Units
Replies: 1
Views: 98

### Re: Heat Capacity Units

Yup! They have the same scale (a change of 1°C is the same as a change of 1K), so you can use them interchangeably. Just remember to keep your units consistent: if you start using celsius, stick with using celsius until you're done with the problem (same goes for Kelvin).
Mon Jan 22, 2018 5:44 pm
Forum: Calculating Work of Expansion
Topic: 8.3
Replies: 3
Views: 234

### Re: 8.3

Well usually pumps are cylindrical, so their volume is pi(r 2 )h. We use the variable "distance" instead of "height" here, but they are technically interchangeable. Since we are depressing the pump, "d" is negative since we are reducing the volume available for gas insi...
Mon Jan 22, 2018 5:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard State
Replies: 5
Views: 299

### Re: Standard State

Standard state is 1 atm pressure, and 1M concentration for solutions. The standard state for hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine is their diatomic molecular form (H 2 , N 2 , O 2 , F 2 , Cl 2 , Br 2 , and I 2 ). If you're asking for what's the standard phase of substa...
Fri Jan 19, 2018 1:27 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Internal Energy/Open System
Replies: 3
Views: 174

### Re: Internal Energy/Open System

Add substance to the system, add heat to the system, or do work on the system.
Wed Jan 17, 2018 4:17 pm
Forum: Phase Changes & Related Calculations
Topic: Accounting for mass in phase changes
Replies: 2
Views: 244

### Re: Accounting for mass in phase changes

You can always write out units for each of the numbers given to you if it helps. Here, we are given the mass of the substance in grams, but the heat capacities given are MOLAR heat capacities. Therefore, we have to convert grams to moles to use it with the molar heat capacity. However, you can also ...
Wed Jan 17, 2018 4:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.1 systems
Replies: 4
Views: 297

### Re: 8.1 systems

Yup it's considered an open system because as gasoline is burned, it releases gaseous byproducts as well as heat. This indicates a transfer of both substance and heat energy, as open systems ten to do.
Wed Jan 17, 2018 1:35 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Energy Change in an Isolated System
Replies: 4
Views: 320

### Re: Energy Change in an Isolated System

Yup, that's pretty much describing the first law of thermodynamics, which states that the internal energy in an isolated system will not change.
Wed Jan 17, 2018 1:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Reaction Enthalpies with Bond Enthalpies
Replies: 2
Views: 185

### Re: Calculating Reaction Enthalpies with Bond Enthalpies

Other methods are probably better to calculate enthalpies. However, I doubt that there will be questions on the test that will give you enough info to calculate enthalpy through multiple methods in the same question. More likely is the possibility that they will ask you to calculate the bond enthalp...
Wed Jan 17, 2018 9:16 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: molar heat capacity of a monatomic ideal gas
Replies: 1
Views: 210

### Re: molar heat capacity of a monatomic ideal gas

I believe that and the equipartition theorem won't be on the test since Dr. Lavelle didn't cover it and it doesn't show up in the lecture outline for the chapter on his website.
Wed Jan 10, 2018 9:09 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: R in the equation
Replies: 2
Views: 175

### Re: R in the equation

R is just a constant that was derived to cancel out units to yield the unit of Joules for work. I believe the units are J/K-1•mol-1, which cancels out the units for n and T in the equation and leaves Joules.
Tue Jan 09, 2018 10:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Figure 8.26
Replies: 1
Views: 129

### Re: Figure 8.26

This is an exception because of water's special properties. Usually, the heat capacity of solids is greater than that of liquids, so the slope for the transition from solid to liquid is more gradual/less steep than the slope for the transition from liquid to gas.
Tue Jan 09, 2018 10:35 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: systems [ENDORSED]
Replies: 5
Views: 357

### Re: systems[ENDORSED]

The way a thermometer works is that mercury expands when it absorbs heat. This absorption of heat is responsible for mercury rising in a thermometer under warm conditions. Since energy can still be transferred, it is considered a closed system rather than an isolated one.
Wed Dec 06, 2017 7:30 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: What is electron-withdrawing Power?
Replies: 1
Views: 339

### Re: What is electron-withdrawing Power?

Electron withdrawing power is the ability of the ion of an acid to pull the electrons that it accepts after it gives away a proton. Ions with low electron withdrawing power can't hold easily the extra electrons it accepted, so they are more likely to steal back another proton and revert back to the ...
Wed Dec 06, 2017 7:16 pm
Forum: Conjugate Acids & Bases
Topic: HW 12.45
Replies: 4
Views: 476

### Re: HW 12.45

Strong bases have weak conjugate acids, and weak bases have strong conjugate acids. A weak conjugate acid will also have a high pK a value (pK a = 10 is more acidic than pK a = 12 because you're talking about an [H + ] concentration of 1 x 10 -10 M vs. 1 x 10 -12 M). So if the pK a value is high, th...
Wed Dec 06, 2017 7:14 pm
Forum: Dipole Moments
Topic: Dipoles: Polar or nonpolar?
Replies: 2
Views: 213

### Re: Dipoles: Polar or nonpolar?

Dipole moments are just short periods of time where electrons are concentrated on one side of the compound more than the other side. This leads to partial positive and partial negative "poles". Thus, the bigger the dipole moment, the greater the polarity of the molecule.
Mon Nov 27, 2017 10:07 pm
Forum: Naming
Topic: why chloro instead of monochloro
Replies: 3
Views: 244

### Re: why chloro instead of monochloro

The "-monochloro" is just redundant. This is because whenever we don't add prefixes to a ligand it is assumed that there is only a single one present in the compound. Prefixes are only reserved for showing we have more than 1 of a ligand present in the compound (i.e. di-, tri-, tetra-, etc...
Mon Nov 27, 2017 10:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AX4E2 lone pairs
Replies: 2
Views: 390

### Re: AX4E2 lone pairs

Picture a compound with 6 bonding atoms to a central atom. This forms an octahedral arrangement. You can replace any atom with an electron pair from this model because every bonding atom forms a 90° bond angle with the central atom and another bonding atom. Removing the first atom gives you a square...
Mon Nov 27, 2017 9:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium 1A Post Module 31
Replies: 1
Views: 175

### Re: Chemical Equilibrium 1A Post Module 31

Whenever you put a stress onto a system at equilibrium, the concentrations of each reactant or product will change to reestablish equilibrium (remember that equilibrium is essentially a glorified ratio of products over reactants). When you say that the reaction "equilibrium has shifted to the l...
Mon Nov 27, 2017 9:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming x is negligible
Replies: 3
Views: 317

### Re: Assuming x is negligible

There are certain conditions where K is a specific value that can allow you to ignore "x" because it is small, but I don't think Dr. Lavelle has taught us this and won't expect us to know it for testing purposes.
Wed Nov 22, 2017 12:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chapter 11, Question 7
Replies: 1
Views: 190

### Re: Chapter 11, Question 7

A) You want to find at what point the amount of the diatomic molecule remains constant. If you look at the 3rd and 4th flask, there is no change in the amount of each substance, so equilibrium is reached by the 3rd flask. B) 6 out of the 11 original diatomic molecules have decomposed going from the ...
Wed Nov 22, 2017 11:34 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium
Replies: 2
Views: 219

### Re: Chemical Equilibrium

Although they are involved in reactions, you don't usually measure the concentration of solids or liquid (when we have an aqueous solution of salt, we say what is the concentration of sodium and chloride ions, but we don't ask for the concentration of water). They don't really have a part to play in...
Mon Nov 13, 2017 4:10 pm
Forum: Hybridization
Topic: Relation of Promotion to Hybridization
Replies: 1
Views: 414

### Re: Relation of Promotion to Hybridization

I'm not quite sure what you mean by promotion, but I'm assuming it means that the s-orbital electrons get promoted to the hybrid sp 3 orbitals. In any case, hybridization demonstrates how carbon can form 4 bonds, since the Aufbau diagram somewhat seems to show that carbon can only form 2 bonds, whic...
Tue Oct 31, 2017 3:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Anion vs Cation electron configuration
Replies: 2
Views: 1191

### Re: Anion vs Cation electron configuration

Ya you have the right idea. I just think of writing anion electron configurations as the same as another element with the same number of electrons. So for example, F1- has the same electron configuration as Neon, even though they are not the same element.
Mon Oct 30, 2017 11:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ions
Replies: 2
Views: 256

### Re: Ions

Tin is a metal, so it will become a cation (since metals tend to lose electrons as ions). So it is Sn4+, not Sn4-. Hope this helps!
Mon Oct 23, 2017 11:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Energy level for n=3 and n=4?
Replies: 3
Views: 476

### Re: Energy level for n=3 and n=4?

The 3d subshell is higher in energy than the 4s subshell. There is actually a slight difference between energy levels 3 and 4, so that the energy in 4s is just barely below 3d. As you get to higher energy levels, the vague differences in energy also causes the 4f orbitals to begin in the 6th energy ...
Mon Oct 23, 2017 10:59 pm
Forum: Trends in The Periodic Table
Topic: Cations and Anions
Replies: 2
Views: 158

### Re: Cations and Anions

Remember that the electron cloud is responsible for pretty much responsible for all of the volume of an atom. If you add electrons, you increase the volume (especially since e - to e - repulsion will increase if you introduce more electrons, causing them to space out even more). So for anions, they ...
Mon Oct 23, 2017 10:49 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave function question
Replies: 1
Views: 168

### Re: Wave function question

I'm not quite sure what you mean by two dimensional graph, but wave functions (Ψ) are described in three dimensions (x, y, z). That describes where the electron could lie on a 3 dimensional graph. I've seen Dr. Lavelle use Ψ (n, l , m l ) instead of Ψ (x, y, z), which pretty much tells the same info...
Wed Oct 18, 2017 5:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electronic Configuration for d-block elements [ENDORSED]
Replies: 9
Views: 836

### Re: Electronic Configuration for d-block elements[ENDORSED]

The same thing happens for f-orbitals, although to a greater extent. Technically the d-orbitals are open in the 3rd energy level (which is why some elements break the octet rule in bonding), but they are not usually occupied until you have gone through the 4s orbitals. Hope this helps!
Wed Oct 18, 2017 5:31 pm
Forum: DeBroglie Equation
Topic: Homework 1.13/ Rydberg
Replies: 3
Views: 219

### Re: Homework 1.13/ Rydberg

Also if you plug in a larger value for n1 and a smaller value for n2, you get a negative frequency value through the Rydberg equation (which we don't want). The smaller number goes for n1 (we use n1 to determine what wavelength series to look at - i.e. Lymann, Balmer...). Hope this helps!
Tue Oct 10, 2017 12:06 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer and Rydberg series
Replies: 3
Views: 272

### Re: Balmer and Rydberg series

The Balmer series is the set of lines formed through spectroscopy within a certain range of wavelength values. Figure 1.10 in the book shows it off better. Basically what we can take from that page in the book is that the Balmer series has the lower principal quantum number always at n 1 =2. This me...
Mon Oct 09, 2017 11:53 pm
Forum: Properties of Light
Topic: Chapter 1 Question 9
Replies: 4
Views: 373

### Re: Chapter 1 Question 9

To find wavelength, use c = λ x v (c=3x108, λ is wavelength, and v is frequency). To find energy, use E = h x v (E is energy, h is Planck's constant 6.626x10-34). You already have frequency so just plug in the value into these equations. Hope this helps!
Mon Oct 09, 2017 11:48 pm
Forum: Properties of Light
Topic: Experimental Value vs. Empirical Value
Replies: 1
Views: 182

### Re: Experimental Value vs. Empirical Value

Actually you're looking at two different laws in action. The Stefan-Boltzmann law, which relates intensity to temperature, is different from Wien's law, which relates wavelength to temperature. As you can see, we have two different equations relating different things, and so we have different values...
Mon Oct 09, 2017 11:38 pm
Forum: Properties of Light
Topic: Amplitude
Replies: 6
Views: 558

### Re: Amplitude

I believe there might be a formula that has to do with amplitude versus intensity, but I think it has to do with when we consider electromagnetic radiation as a wave, not photons. I think therefore it's something we don't have to know how to do for class purposes (I think it also has to do with only...
Tue Oct 03, 2017 10:27 pm
Forum: Molarity, Solutions, Dilutions
Topic: Writing formulas
Replies: 4
Views: 464

### Re: Writing formulas

I believe Dr. Lavelle said that all the formula names would be provided for you on the test since we don't explicitly cover it in class, but just in case I'd review the very basic rules for naming (prefixes for ionic and molecular compounds, maybe even a couple of polyatomic ion names). But in any c...
Tue Oct 03, 2017 9:10 am
Forum: Empirical & Molecular Formulas
Topic: Percentage Yield M.3
Replies: 2
Views: 418

### Re: Percentage Yield M.3

You are partially right. What you have to realize is that they don't actually give you all the information you need. Remember that BOTH the theoretical yield and the actual yield have to be for the same thing (in this case, for CO2). What you have to do with the 42.73g of CaCO3 is use stoichiometry ...
Tue Oct 03, 2017 12:05 am
Forum: Molarity, Solutions, Dilutions
Topic: HW Problem E35
Replies: 5
Views: 642

### Re: HW Problem E35

Ya it most likely is a mistake because there is no reason that you should divide by the final mass since you are trying to compare to the initial mass. If you pretend that there is one mole of hydroxyapatite to start with, and it all turns to fluorapatite, then you would say that there is a 1.99g in...