Search found 101 matches
- Mon Mar 09, 2020 1:46 am
- Forum: First Order Reactions
- Topic: Homework 7B.7
- Replies: 1
- Views: 151
Homework 7B.7
Substance A decomposes in a first-order reaction and its half-life is 355 s. How much time must elapse for the concentration of A to decrease to (a) one-eighth of its initial concentration; (b) one-fourth of its initial concentration; (c) 15% of its initial concentration; (d) one-ninth of its initia...
- Mon Mar 09, 2020 1:40 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Homework 7E.3
- Replies: 1
- Views: 186
Homework 7E.3
The presence of a catalyst provides a reaction pathway in which the activation energy of a certain reaction is reduced from 125 kJ?mol−1 to 75 kJ?mol−1. (a) By what factor does the rate of the reaction increase at 298 K, all other factors being equal? (b) By what factor would the rate change if the ...
- Mon Mar 09, 2020 1:34 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Homework 7C11
- Replies: 2
- Views: 169
Homework 7C11
According to the solutions manual, " At equilibrium, rates of forward and reverse reactions are equal, not rate constants?" Is there such thing as a rate constant of a forward or reverse reaction or are they just referred to as rates?
- Mon Mar 09, 2020 1:30 am
- Forum: First Order Reactions
- Topic: Units for t
- Replies: 30
- Views: 1368
Units for t
What are the correct units for t? The solutions manual leaves it in minutes but aren't the correct units in seconds?
- Mon Mar 09, 2020 1:28 am
- Forum: First Order Reactions
- Topic: First Order Equation
- Replies: 3
- Views: 288
First Order Equation
When solving for k, do both of these derivations mean the same thing: (ln([Ao]/[[A]))/t AND (ln[A]/[Ao])/-t? The book uses the first equation but I'm not sure if the two equations mean the same thing because I am getting a different answer.
- Thu Mar 05, 2020 6:38 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Potential
- Replies: 3
- Views: 322
Potential
What's the difference between minimum potential and maximum potential? Does minimum potential mean Standard E Cell and maximum potential mean Wmax? If so, what does this mean conceptually?
- Thu Mar 05, 2020 6:34 pm
- Forum: Balancing Redox Reactions
- Topic: Cathode and Anode
- Replies: 24
- Views: 1655
Cathode and Anode
Why can we assume the cell can do work when the E value at the Cathode is bigger than the E value at the Anode?
- Thu Mar 05, 2020 6:31 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M5
- Replies: 2
- Views: 202
6M5
For 6M5, the cell diagram included Hg(l). Why wasn't there a solid metal included at the oxidation side? Does Hg(l) still work as a conductor even if it is in liquid form?
- Thu Mar 05, 2020 6:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 6
- Views: 471
Cell Diagram
Are liquids the only thing we don't include in cell diagrams?
- Thu Mar 05, 2020 6:21 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Standard Delta G vs Non-Standard Delta G
- Replies: 4
- Views: 363
Standard Delta G vs Non-Standard Delta G
Does the standard delta G (with the degree sign) mean the reaction is at equilibrium? Can you also find standard delta G (with the degree sign) with the Q value or does it only with the equilibrium constant, K?
- Tue Mar 03, 2020 9:13 am
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: 6O.1
- Replies: 1
- Views: 172
6O.1
A 1.0 m NiSO4(aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction. (c) With no overpotential at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis? Does the minimum potential mean t...
- Wed Feb 26, 2020 2:41 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M11
- Replies: 2
- Views: 223
6M11
How do we know Cobalt is a solid in 6M11 part a?
- Wed Feb 26, 2020 2:27 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M7
- Replies: 3
- Views: 244
6M7
I know a more negative (less positive) standard reduction potential leads to a stronger metal as a reducing agent. For this problem, how do we know which standard reduction potential to use in the appendix when there are many of them for the same element?
- Wed Feb 26, 2020 12:34 am
- Forum: Balancing Redox Reactions
- Topic: Homework 6M1
- Replies: 5
- Views: 474
Homework 6M1
A student was given a standard Cu(s)|Cu2+(aq) half-cell and another half-cell containing an unknown metal M in 1.00 M M(NO3)2(aq) and formed the cell M(s)|M+1(aq)||Cu2+(aq)|Cu(s). The cell potential was found to be -0.689 V. What is the value of E(M+2/M)? In this problem, im assuming the Cu(s)|Cu2+(...
- Tue Feb 25, 2020 9:13 am
- Forum: Balancing Redox Reactions
- Topic: Which equation do we flip?
- Replies: 6
- Views: 418
Which equation do we flip?
When you balance redox reactions and you end up with the same amount of added electrons on the same side, how do you know which equation to flip to cancel out the electrons? Do we flip the anode or the cathode or is it dependent on the E value of each?
- Tue Feb 25, 2020 9:08 am
- Forum: Balancing Redox Reactions
- Topic: Homework L3 part d
- Replies: 1
- Views: 183
Homework L3 part d
d) Balance 1/2 rxns: Pt(s) | O2 | H+ || OH- | O2 For part d, I tried balancing the oxidation half-reaction by adding to waters on the right to balance out the oxygens. That would make 5 H+ in total so I balanced out those H+s by adding 5H+ to the left side. The final charge I got on the left was 5 a...
- Fri Feb 21, 2020 6:10 pm
- Forum: Balancing Redox Reactions
- Topic: Homework L3 part d
- Replies: 1
- Views: 141
Homework L3 part d
When it comes to balancing the equation for the cell reaction for each of the following galvanic cells, if OH- is given is there another method we follow? How do we find the two balanced 1/2 reactions for the oxidation and reduction rxns in this problem?
- Fri Feb 21, 2020 5:57 pm
- Forum: Balancing Redox Reactions
- Topic: Charge of oxygen
- Replies: 15
- Views: 782
Charge of oxygen
Will the charge of O2 always be -2 even if it stands alone? Can someone explain the charges of different kinds of oxygen such as O and O3 and up?
- Fri Feb 21, 2020 4:49 pm
- Forum: Balancing Redox Reactions
- Topic: Homework 6K5
- Replies: 1
- Views: 182
Homework 6K5
For homework 6K5, when balancing the O3 --> O2 reaction, the solutions manual shows that H2O cancels out after balancing the H. Why would this occur?
- Fri Feb 21, 2020 3:19 pm
- Forum: Balancing Redox Reactions
- Topic: Homework 6K1
- Replies: 4
- Views: 392
Homework 6K1
The following reaction is used in the acidic solution in the Breathalyzer test to determine the level of alcohol in the blood:
H+(aq) + (Cr2O7)-2(aq) + C2H5OH(aq) ---> (Cr)3+(aq) + C2H4O(aq) + H2O(l)
Is the overall net charge of both C2H5OH and C2H4O zero or one?
H+(aq) + (Cr2O7)-2(aq) + C2H5OH(aq) ---> (Cr)3+(aq) + C2H4O(aq) + H2O(l)
Is the overall net charge of both C2H5OH and C2H4O zero or one?
- Thu Feb 20, 2020 5:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Homework 6M.1
- Replies: 1
- Views: 129
Homework 6M.1
A student was given a standard Cu(s)|Cu2+(aq) half-cell and another half-cell containing an unknown metal M in 1.00 M M(NO3)2(aq) and formed the cell M(s)|M+1(aq)||Cu2+(aq)|Cu(s). The cell potential was found to be -0.689 V. What is the value of E(M+2/M)? I'm confused about this problem. How can you...
- Fri Feb 14, 2020 1:12 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Potential
- Replies: 4
- Views: 431
Cell Potential
The textbook's definition of cell potential is vague. Is it a measure of how much voltage or electrical energy a cell has? How does this relate to the half-reactions of redox reactions and oxidation? Is the electrical energy caused by the movement or the difference in electrons on both sides?
- Fri Feb 14, 2020 1:06 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrochemical cell
- Replies: 4
- Views: 320
Electrochemical cell
I'm confused about how an electrochemical cell operates. I understand that oxidation occurs at the anode and reduction occurs at the cathode, but overall what is the charge of the cell and what is the meaning of this circuit?
- Fri Feb 14, 2020 12:51 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: K and Q and G
- Replies: 6
- Views: 460
K and Q and G
I understand that reaction quotient (Q) measures the relative amounts of products and reactants at any time in the reaction at any particular point and equilibrium constant (K) describes the reaction at equilibrium. I also know that K and Q can be compared so that we can tell which way the reaction ...
- Fri Feb 14, 2020 12:39 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G
- Replies: 6
- Views: 372
Delta G
Why do we solve for delta G of the reaction using the delta G with the degree sign? I know that the degree sign indicates that the reaction is at standard temperature and pressure but what is the significance of this?
- Fri Feb 14, 2020 12:35 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: PV=nRT
- Replies: 5
- Views: 320
PV=nRT
How do we know when we can use PV=nRT to find a missing value? When we are given the change in one or more of these variables, do we plug it in as delta for the variable(s)? For example, if we want to find Pressure and the problem gives us the change in Volume and moles, would we solve for P using t...
- Fri Feb 07, 2020 2:48 am
- Forum: Phase Changes & Related Calculations
- Topic: Homework 4C 13
- Replies: 7
- Views: 394
Homework 4C 13
An ice cube of mass 50.0 g at 0.0 8C is added to a glass containing 400.0 g of water at 45.0 8C. What is the final temperature of the system (see Tables 4A.2 and 4C.1)? Assume that no heat is lost to the surrounding. For this problem, I understand that we find the total heat for ice and total heat f...
- Fri Feb 07, 2020 12:03 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Monatomic ideal gases
- Replies: 2
- Views: 150
Monatomic ideal gases
Can someone explain when to use the ideal gas constant for monatomic ideal gases? What is are some examples of a monoatomic ideal gas?
- Thu Feb 06, 2020 11:29 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat Capacity at Constant V/P
- Replies: 1
- Views: 63
Heat Capacity at Constant V/P
I understand that heat capacity at a constant volume is (delta U)/(delta T) bc at constant volume delta U equals q. However, why is heat capacity at constant pressure (delta H)/(delta T)?
- Thu Feb 06, 2020 11:19 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H and qp
- Replies: 8
- Views: 213
Delta H and qp
When can we assume enthalpy (delta H) and heat (qp) are equal? Can we always use them interchangeably? Why or why not?
- Wed Feb 05, 2020 4:10 pm
- Forum: Calculating Work of Expansion
- Topic: Reversible vs. Irreversible
- Replies: 3
- Views: 230
Re: Reversible vs. Irreversible
An expansion is reversible when the temperature is constant. This process is gradual and requires more work. It is reversible because everything is at equilibrium and therefore entropy is equal to zero. During a reversible expansion, work is negative and the system is losing energy by expanding; how...
- Wed Jan 29, 2020 10:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: State Functions
- Replies: 6
- Views: 207
State Functions
Why aren't heat and work state functions?
- Wed Jan 29, 2020 9:56 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat Capacity
- Replies: 1
- Views: 95
Heat Capacity
What is the significance of finding the heat capacity?
- Wed Jan 29, 2020 9:40 pm
- Forum: Phase Changes & Related Calculations
- Topic: Work Equation
- Replies: 3
- Views: 166
Work Equation
What is the conceptual significance of having the negative sign in the equation: w=-(external pressure) x (change in volume)?
- Wed Jan 29, 2020 8:51 pm
- Forum: Phase Changes & Related Calculations
- Topic: Open vs Isolated System
- Replies: 15
- Views: 1347
Open vs Isolated System
What keywords would help you determine whether a system is closed or isolated? I find the two very similar and am having difficulty differentiating them when looking at examples.
- Wed Jan 29, 2020 8:38 pm
- Forum: Phase Changes & Related Calculations
- Topic: Homework 4A.9
- Replies: 3
- Views: 170
Homework 4A.9
For homework problem 4A.9: A piece of copper of mass 20.0 g at 100.0 8C is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0 8C. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings. The solutions manual states that we so...
- Thu Jan 23, 2020 4:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Internal Energy Change
- Replies: 3
- Views: 145
Internal Energy Change
What is the conceptual meaning of the internal energy change and how do we calculate it?
- Thu Jan 23, 2020 4:49 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa/Pkb vs pH/pOH
- Replies: 3
- Views: 171
pKa/Pkb vs pH/pOH
How do pKa and pKb relate to pH and pOH?
- Thu Jan 23, 2020 4:45 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Partial Pressure vs Pressure
- Replies: 7
- Views: 266
Partial Pressure vs Pressure
When we look at the changes and effects using Le Chatelier's Principle, is Partial Pressure different from Pressure? For example, if the Partial Pressure of one of the products increases, will there be an increase in the Partial Pressure of the reactants. On the other hand, if Pressure increases in ...
- Thu Jan 23, 2020 4:41 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K value
- Replies: 7
- Views: 243
K value
When we decide whether or not to exclude the "minus x" in the denominator do we compare the K value to 10^-3 or 10^-5?
- Wed Jan 22, 2020 10:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6D 15
- Replies: 1
- Views: 64
6D 15
For problem 6D)15, how do we find pH? How do you find the Ka value that we use for the equation to figure out the x value?
- Thu Jan 16, 2020 10:02 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K comparison
- Replies: 4
- Views: 223
K comparison
How do we know when to compare K to a value greater than or less than 1 and when to compare K to the values 10^3 and 10^-3?
- Thu Jan 16, 2020 10:00 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5 percent rule
- Replies: 10
- Views: 555
5 percent rule
In class, Lavelle mentioned something called the 5 % rule. I didn't really understand this concept. Can someone explain when to use this? Does it only apply to acids and bases ICE calculations?
- Thu Jan 16, 2020 9:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acid and Base Equilibria
- Replies: 1
- Views: 46
Acid and Base Equilibria
Why do solutions of weak acids have higher pH values than solutions of strong acids at the same concentration? Does this have something to do with the fact that weak acids have stronger conjugate bases?
- Thu Jan 16, 2020 9:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percentage Ionization
- Replies: 2
- Views: 76
Percentage Ionization
How do you calculate the percentage ionization of a weak acid or a weak base? What does this calculation mean conceptually?
- Thu Jan 16, 2020 9:52 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: ICE table
- Replies: 11
- Views: 410
ICE table
How do we know when to use the ICE table for acids and bases? Do we have to memorize which are strong acids and strong bases?
- Fri Jan 10, 2020 5:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pure Substance
- Replies: 5
- Views: 283
Pure Substance
Why is the activity of pure substances equal to zero?
- Fri Jan 10, 2020 5:07 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Alternative Forms [ENDORSED]
- Replies: 2
- Views: 178
Alternative Forms [ENDORSED]
What is the purpose of having alternative forms of the equilibrium constant?
- Fri Jan 10, 2020 5:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Activity of Substance Versus Coefficient
- Replies: 1
- Views: 103
Activity of Substance Versus Coefficient
What is the difference between the Activity of a Substance J (denoted a sub j) and the Activity Coefficient?
- Fri Jan 10, 2020 5:04 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law
- Replies: 6
- Views: 214
Ideal Gas Law
What is the purpose of the ideal gas law and which reactions can use it as an approximation?
- Fri Jan 10, 2020 5:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G1
- Replies: 2
- Views: 115
5G1
When does the amount of reactant and product affect the reaction? In HW 5G1, these two statements are false: An equilibrium rxn is not affected by increasing the concentration of products. If one starts with a higher pressure of reactant, the equilibrium constant will be larger. In this problem are ...
- Wed Dec 04, 2019 1:36 pm
- Forum: Bronsted Acids & Bases
- Topic: HOI vs HOCl
- Replies: 3
- Views: 396
HOI vs HOCl
HI is a stronger acid than HCl because I has a larger atom radius than Cl and HI has a weaker bond than HCl which makes HI dissociate completely very easily.
However, when looking at HOI and HOCl, why is HOCl a stronger acid?
However, when looking at HOI and HOCl, why is HOCl a stronger acid?
- Wed Dec 04, 2019 1:29 pm
- Forum: Naming
- Topic: latin names
- Replies: 3
- Views: 250
latin names
When do you use "ferrate" when naming molecular compounds?
- Tue Dec 03, 2019 11:23 pm
- Forum: Hybridization
- Topic: HW 2.47
- Replies: 1
- Views: 77
HW 2.47
In this problem, we had to assign a hybridization scheme to the Sb atoms. In the solutions manual, the single bond between C and H is sigma(C 2sp^2, H 1s) what does the 2 and 1 represent? Is if the n value of each atom?
- Tue Dec 03, 2019 9:34 pm
- Forum: Bronsted Acids & Bases
- Topic: How to determine whether a molecule is an acid or a base
- Replies: 5
- Views: 334
How to determine whether a molecule is an acid or a base
How is NH3 a base?
- Tue Dec 03, 2019 4:08 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Determining binding sites
- Replies: 3
- Views: 179
Determining binding sites
Why is water always a monodentate ligand if there are two pairs of lone pairs?
- Sat Nov 30, 2019 5:03 pm
- Forum: *Stereochemistry
- Topic: Isomers
- Replies: 2
- Views: 741
Isomers
What is the difference between a structural isomer and a stereoisomer?
Charge
How do we determine the charge of a cation?
- Sat Nov 30, 2019 4:56 pm
- Forum: Bronsted Acids & Bases
- Topic: Weak Acid
- Replies: 2
- Views: 154
Weak Acid
Why is acetic acid considered a weak acid?
- Sat Nov 30, 2019 4:53 pm
- Forum: Bronsted Acids & Bases
- Topic: Weak/Strong acids
- Replies: 2
- Views: 158
Weak/Strong acids
In a reaction, how can you tell if a molecule/ion has been incompletely or completely deprotonated?
- Sat Nov 30, 2019 4:50 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acids and Bases
- Replies: 3
- Views: 211
Bronsted Acids and Bases
Since water can donate a proton and accept a proton, is it considered both a bronsted acid and bronsted base? If so, what are other compounds that have this characteristic?
- Fri Nov 22, 2019 10:25 am
- Forum: Hybridization
- Topic: sp hybridization
- Replies: 4
- Views: 337
sp hybridization
How do linear molecules have an sp hybridization?
- Fri Nov 22, 2019 10:23 am
- Forum: Lewis Structures
- Topic: Drawing Lewis Structures
- Replies: 7
- Views: 600
Drawing Lewis Structures
If we are given a molecule with multiple carbons like C5H5N, will the lewis structure will always be in the form of a ring of carbons (and one N)? Also, do we refer to the central atoms as the carbon or is there no central atom?
- Fri Nov 22, 2019 10:22 am
- Forum: Octet Exceptions
- Topic: Homework 2E.19d
- Replies: 3
- Views: 240
Homework 2E.19d
For 2E19d on the homework, is SnCl2 a radical? In other words, does the central atom, Sn, not need to fill its octet? Which atoms can this trend occur in?
- Fri Nov 22, 2019 10:20 am
- Forum: Hybridization
- Topic: Hybridization
- Replies: 3
- Views: 294
Hybridization
Why does the bond angle between two hybrid orbitals increase as the s-character of the hybrids is increased?
- Fri Nov 22, 2019 10:18 am
- Forum: Bond Lengths & Energies
- Topic: Boiling Point vs Melting Point
- Replies: 5
- Views: 661
Boiling Point vs Melting Point
From my understanding, the boiling point and melting point both increase as the intermolecular forces increase in strength but what is the difference between the two?
- Fri Nov 15, 2019 12:16 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral
- Replies: 5
- Views: 413
Octahedral
What is the difference between octahedral, square pyramidal, and square planar?
- Fri Nov 15, 2019 12:14 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering Molecular Geometric Shapes
- Replies: 2
- Views: 158
Remembering Molecular Geometric Shapes
Is there a conceptual way of how you can determine the molecular geometric shape of a molecule or do we just have to memorize the amount of bonding and lone pairs of different molecular geometric shapes and assign the shape that way?
- Fri Nov 15, 2019 12:11 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Geometry vs Electron Geometry
- Replies: 2
- Views: 146
Molecular Geometry vs Electron Geometry
What's the difference between the electron geometric shape and the molecular geometric shape of a molecule?
- Fri Nov 15, 2019 12:07 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Determining Bond Angle
- Replies: 3
- Views: 275
Determining Bond Angle
If there are lone pairs around the central atom, will the bond angles always be less than the intended degrees? For example, SO2 has one lone pair and has bond angles of less than 120 degrees. On the other hand, BCl3 has no lone pairs and has bond angles of 120 degrees.
- Thu Nov 14, 2019 7:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Homework 2E.1
- Replies: 4
- Views: 187
Homework 2E.1
How can we tell if a molecule has lone pairs of electrons on the central atom or not?
- Thu Nov 07, 2019 9:48 am
- Forum: Photoelectric Effect
- Topic: Maximum Wavelength
- Replies: 2
- Views: 273
Maximum Wavelength
How do you find the maximum wavelength in which an electron can be ejected?
- Thu Nov 07, 2019 9:45 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Hw 1.43 (sixth edition)
- Replies: 1
- Views: 162
Hw 1.43 (sixth edition)
1.43 What is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm? Model the atom as a one-dimensional box with a length equal to the diameter of the actual atom. In this problem, does the 350 pm represent delta x? Will it always be talking about the...
- Thu Nov 07, 2019 9:43 am
- Forum: Photoelectric Effect
- Topic: Midterm 1
- Replies: 9
- Views: 706
Midterm 1
How do you find the number of photons a light can generate if you are given the amount of energy the light emits and its wavelength?
- Thu Nov 07, 2019 9:39 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Bohr Frequency
- Replies: 6
- Views: 343
Bohr Frequency
When energy is absorbed, is the n value going up or down?
- Thu Nov 07, 2019 9:37 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg
- Replies: 3
- Views: 256
Heisenberg
What is delta p and delta x in the Heisenberg Indeterminacy (Uncertainty) Equation?
- Fri Nov 01, 2019 1:32 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 4
- Views: 190
Resonance
Why are resonance structures more reactive?
- Fri Nov 01, 2019 1:31 pm
- Forum: Octet Exceptions
- Topic: Exceptions to the Octet Rule
- Replies: 3
- Views: 111
Exceptions to the Octet Rule
What is the difference between radicals and biradicals?
- Fri Nov 01, 2019 1:28 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework 2D #15
- Replies: 5
- Views: 303
Homework 2D #15
If we are given a list of molecules, such as CF4, CCl4, and CBr4, how can we tell which molecule is predicted to have the strongest CX bond, where X is a halogen? (reference: problem 2D15)
- Fri Nov 01, 2019 1:27 pm
- Forum: Lewis Structures
- Topic: Expanded Valence Shells
- Replies: 4
- Views: 234
Expanded Valence Shells
When we do Lewis Dot Diagrams, how do we know which atoms can have expanded valence shells? Also, if they are able to expand their valence shells, how many extra valence electrons are they able to possess?
- Fri Nov 01, 2019 1:25 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Homework 2D #5
- Replies: 1
- Views: 151
Homework 2D #5
For 2A5 in the homework, how come when we find the ground state e-configuration for Bi+3 we include 6s^2 but we don’t include it for the ground state e- configuration for TI+3?
- Sat Oct 26, 2019 4:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: Expanded Valence Shells
- Replies: 4
- Views: 149
Expanded Valence Shells
Why are Phosphorus, Sulfur, and Chlorine able to accommodate more than 8 valence electrons? Are there any other elements with this characteristic?
- Sat Oct 26, 2019 4:26 pm
- Forum: Lewis Structures
- Topic: Homework 2C #15
- Replies: 3
- Views: 177
Homework 2C #15
When given a set of lewis structures like problem 2C15 in textbook where there are four resonance structures shown, how do we know which has the lowest energy?
- Sat Oct 26, 2019 4:23 pm
- Forum: Lewis Structures
- Topic: Lewis Structure
- Replies: 5
- Views: 250
Lewis Structure
Which elements mostly show up in the center of the Lewis Structure and why?
- Sat Oct 26, 2019 4:22 pm
- Forum: Electronegativity
- Topic: Transition Metals and Periodic Table Trends
- Replies: 2
- Views: 209
Transition Metals and Periodic Table Trends
In the lecture, Lavelle mentioned that transition metals vary in valence electrons. Mn has 7 valence electrons and it is in the seventh column in the transition metal groups. How do we know when to determine a transition metal’s valence electrons based on column number and when not to?
- Sat Oct 26, 2019 4:21 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 7
- Views: 459
Formal Charge
What is the importance of finding the formal charge of an atom?
- Fri Oct 18, 2019 3:45 pm
- Forum: DeBroglie Equation
- Topic: Linear Momentum
- Replies: 6
- Views: 243
Linear Momentum
What is linear momentum and how do we solve for it?
- Fri Oct 18, 2019 3:45 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra
- Replies: 5
- Views: 177
Atomic Spectra
Why are there gaps and certain chunks of vertical lines on the atomic spectra and what do they represent?
- Fri Oct 18, 2019 3:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Homework Problem 1A #3
- Replies: 3
- Views: 178
Homework Problem 1A #3
In problem 1A.3, what does it mean by the “extent of change in the electrical field”? Is it referring to the amplitude of the wave? In that case, if the frequency decreases, will the extent of change also decrease?
- Fri Oct 18, 2019 3:43 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum vs Classical
- Replies: 5
- Views: 211
Quantum vs Classical
What is the difference between classical mechanics and quantum mechanics?
- Fri Oct 18, 2019 3:42 pm
- Forum: Photoelectric Effect
- Topic: Threshold Energy
- Replies: 7
- Views: 531
Threshold Energy
What happens if the energy of light matches the threshold energy level? What would happen to the electron(s) on the metal surface?
- Sat Oct 12, 2019 10:42 pm
- Forum: DeBroglie Equation
- Topic: Learning Objective
- Replies: 1
- Views: 110
Learning Objective
What is the de Broglie particle-wave duality for the election and proton? How do we derive it?
- Sat Oct 12, 2019 10:31 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Lyman and Balmer
- Replies: 3
- Views: 190
Lyman and Balmer
What is the difference between the Lynam and Balmer series?
- Sat Oct 12, 2019 10:22 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect and Photons
- Replies: 6
- Views: 286
Photoelectric Effect and Photons
Can someone explain what a photon exactly is and how it relates to the Photoelectric Effect? I can't seem to comprehend it in simple terms.
- Sat Oct 12, 2019 10:13 pm
- Forum: Properties of Electrons
- Topic: Wavelength and Electrons
- Replies: 4
- Views: 269
Re: Wavelength and Electrons
The wavelength of an electron can be determined with the de Broglie equation: Wavelength = Planck's constant/ (Mass x Velocity).
- Sat Oct 12, 2019 10:04 pm
- Forum: Properties of Light
- Topic: Frequency vs. Wavelength
- Replies: 15
- Views: 730
Re: Frequency vs. Wavelength
Frequency, denoted as Greek letter nu, represents the number of waves that passes a given point in a certain amount of time. Wavelength, written as Greek letter lambda, is the distance between two points on two adjacent waves. Frequency and wavelength are inversely proportional. This means short wav...
- Thu Oct 03, 2019 10:34 pm
- Forum: Limiting Reactant Calculations
- Topic: Basic Question
- Replies: 11
- Views: 583
Re: Basic Question
Hi Candice! The limiting reaction is when a reaction has more of one reactant and less of another causing the amount of product to be limited. Therefore, it is very unlikely for there to be only two limiting reactants. In that case, they would have to be the same amount of reactants which would not ...
- Thu Oct 03, 2019 10:20 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molar Mass
- Replies: 5
- Views: 809
Re: Molar Mass
The molar mass does not change when you have an ion. For example, Fe and Fe3+ both have a molar mass of 55.845g/mol. The only difference between the atom (Fe) and ion (Fe3+) is that Fe3+ has 3 electrons. The molar mass remains the same because electrons do not have a large mass compared to the entir...
- Thu Oct 03, 2019 9:53 pm
- Forum: SI Units, Unit Conversions
- Topic: 2.Mass Percentage and Decimal Rounding:
- Replies: 10
- Views: 487
2.Mass Percentage and Decimal Rounding:
When finding the mass percentage, is there a certain decimal we are supposed to round to?
- Thu Oct 03, 2019 9:50 pm
- Forum: SI Units, Unit Conversions
- Topic: 1.Homework 1 Problem: G5
- Replies: 2
- Views: 135
1.Homework 1 Problem: G5
Problem: A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a flask to obtain (a) 2.15 mmol Na; (b) 4....