Search found 101 matches
- Sat Mar 13, 2021 10:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electromotive Force
- Replies: 5
- Views: 340
Re: Electromotive Force
Hi! My understanding is that electromotive force and cell potential are the same! Hope this helps!
- Sat Mar 13, 2021 10:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: porous disk
- Replies: 7
- Views: 386
Re: porous disk
Hey, I think they function relatively the same. With a salt bridge, the reduction and oxidation reaction need to be in separate cells. However, a cell with a porous disk can contain both the oxidation and reduction reactions in the same cell, and the salts simply pass through the disk
- Sat Mar 13, 2021 2:27 pm
- Forum: Student Social/Study Group
- Topic: Textbook Q 6M.7
- Replies: 3
- Views: 277
Re: Textbook Q 6M.7
The more negative the standard reduction potential, the stronger the metal is as a reducing agent. So the standard reduction potential of Cu is greater, or more positive than that of Cr.
- Fri Mar 12, 2021 4:49 pm
- Forum: Balancing Redox Reactions
- Topic: Textbook Question 6K.3 d)
- Replies: 4
- Views: 305
Re: Textbook Question 6K.3 d)
2 H2O + Cl2 --> 2 HOCl + 2 H+ + 2e-
2 H2O + 2Cl2 + 2e- --> 2HOCl + 2H+ + 2Cl- + 2e-
so Cl2 is both the oxidizing and the reducing agent
2 H2O + 2Cl2 + 2e- --> 2HOCl + 2H+ + 2Cl- + 2e-
so Cl2 is both the oxidizing and the reducing agent
- Fri Mar 12, 2021 4:45 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Textbook Problem 7.27 Focus Exercise
- Replies: 2
- Views: 241
Re: Textbook Problem 7.27 Focus Exercise
First use the equation for half-life of a first order reaction to determine k. Then use the first order reaction equation ln([A]/[Ao]) = -kt to determine the ratio of the current concentration of the drug to the initial concentration. You should get 0.735. Then multiply this by the initial amount of...
- Fri Mar 12, 2021 4:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: When to use Platinum
- Replies: 14
- Views: 712
Re: When to use Platinum
You should use platinum when there is no solid metal conductor. There may be aqueous metal however this would still need a platinum conductor.
- Fri Mar 12, 2021 4:38 pm
- Forum: Second Order Reactions
- Topic: Sapling #12 Week9/10
- Replies: 7
- Views: 435
Sapling #12 Week9/10
A particular reactant decomposes with a half‑life of 129 s when its initial concentration is 0.322 M. The same reactant decomposes with a half‑life of 213 s when its initial concentration is 0.195 M. I'm a bit confused how you would approach this problem to determine what the reaction order is.
- Fri Mar 12, 2021 4:32 pm
- Forum: First Order Reactions
- Topic: Sapling Week 9/10 #13
- Replies: 6
- Views: 368
Sapling Week 9/10 #13
The mechanism proposed for the oxidation of iodide ion, I−, by the hypochlorite ion, ClO−, in aqueous solution is shown. ClO−(aq)+H2O(l)⇌HClO(aq)+OH−(aq)fast in both directions I−(aq)+HClO(aq)→HIO(aq)+Cl−(aq) slow HIO(aq)+OH−(aq)→IO−(aq)+H2O(l) fast Complete the rate law for the formation of IO− imp...
- Fri Mar 12, 2021 4:27 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Activation Energy and Temperature
- Replies: 2
- Views: 550
Re: Activation Energy and Temperature
The rate constant of a reaction is temperature dependent. Raising the temperature will increase the rate constant of the reaction with the greater activation energy more than that of the reaction with the lower activation energy. In this case, the forward reaction has the higher activation energy, s...
- Mon Mar 08, 2021 2:53 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Low versus High Activation Energy
- Replies: 3
- Views: 197
Re: Low versus High Activation Energy
this is because the slope for these lines equals -Ea/R. So a higher activation energy will have a steeper slope than a low activation energy.
- Sun Mar 07, 2021 11:58 pm
- Forum: General Rate Laws
- Topic: Rate determining step
- Replies: 38
- Views: 1386
Re: Rate determining step
Because it is the slowest step, you can think of it kinda as the one that holds up the line or the limiting reactant. The reaction can only occur as fast as its slowest step so that is why the slow step is so important for rate.
- Sun Mar 07, 2021 11:56 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Sapling Week 5/6 #15
- Replies: 2
- Views: 199
Re: Sapling Week 5/6 #15
To calculate ΔG∘, you must first calculate ΔH∘ and ΔS∘ of A+B-->2C.(multiply the second equation values by -2). After converting ΔS∘ to kJ/K, use the equation ΔG = ΔH∘ - TΔS∘ to solve.
- Sun Mar 07, 2021 11:50 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook Problem 6.51
- Replies: 2
- Views: 165
Re: Textbook Problem 6.51
A negatively charged electrolyte flows from the cathode to the anode.
- Sun Mar 07, 2021 11:49 pm
- Forum: Second Order Reactions
- Topic: Breaking down / explaining 2nd order reactions
- Replies: 7
- Views: 386
Re: Breaking down / explaining 2nd order reactions
Second order means that when you plot 1/[A] vs time, you will get a straight line. Second order also means it requires two molecules to react/collide for the reaction to occur.
- Sun Mar 07, 2021 11:47 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Textbook Problem 6.43
- Replies: 3
- Views: 775
Re: Textbook Problem 6.43
The answer would be neither. As long as the redox equation is correctly balanced, it makes no difference to Ecell* and Ecell what the stoichiometric coefficients are.
- Sat Feb 20, 2021 1:59 pm
- Forum: Balancing Redox Reactions
- Topic: First Lecture Galvanic Cell
- Replies: 7
- Views: 405
Re: First Lecture Galvanic Cell
I think the solutions can be different, but in the lecture he had a solution of Zinc (Zn --> Zn 2+ + 2e-) on the left side where the negative anode is. And a solution of copper (Cu+2 + 2e- --> Cu) on the right side where the positive cathode is. I think the only significant part is that the solution...
- Sat Feb 20, 2021 1:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Textbook 4A.13
- Replies: 3
- Views: 363
Textbook 4A.13
A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q = -23.50 kJ), resulting in a temperature rise of 7.32 C. In a subsequent experiment, 100.0 mL of 0.200 m HBr(aq) and 100.0 mL of 0.200 m KOH(aq) were ...
- Sat Feb 20, 2021 1:48 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Textbook 4H.9
- Replies: 4
- Views: 280
Textbook 4H.9
Container A is filled with 1.0 mol of the atoms of an ideal monatomic gas. Container B has 1.0 mol of atoms bound together as diatomic molecules that are not vibrationally active. Container C has 1.0 mol of atoms bound together as diatomic molecules that are vibrationally active. The containers all ...
- Sat Feb 20, 2021 1:40 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Textbook 4F.17
- Replies: 4
- Views: 408
Textbook 4F.17
Calculate the standard entropy of vaporization of water at 85 C, given that its standard entropy of vaporization at 100 C is 109.0 J/K*mol and the molar heat capacities at constant pressure of liquid water and water vapor are 75.3 J/K*mol and 33.6 J/K*mol, respectively, in this range. Why is that wh...
- Sat Feb 20, 2021 1:31 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Textbook 4A.11
- Replies: 6
- Views: 740
Textbook 4A.11
A calorimeter was calibrated with an electric heater, which supplied 22.5 kJ of energy as heat to the calorimeter and increased the temperature of the calorimeter and its water bath from 22.45 8C to 23.97 8C. What is the heat capacity of the calorimeter? What does heat capacity of the calorimeter me...
- Sun Feb 14, 2021 11:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: HW Question
- Replies: 3
- Views: 198
Re: HW Question
to solve this you will use the equation ΔG = ΔH* - TΔS*. We set ΔG to zero because the boiling point is when the equation (s) --> (l) is at equilibrium. then plug everything into the equation and solve for T. This is your boiling point.
- Sun Feb 14, 2021 11:35 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated System
- Replies: 6
- Views: 313
Re: Isolated System
Isolated systems are almost impossible to make because there will always be some sort of inefficiency and it is impossible to create a perfect system.
- Sun Feb 14, 2021 11:33 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: HW Question
- Replies: 4
- Views: 254
Re: HW Question
the equation you want to use is ΔG = ΔG* + RT ln(Q).First solve for Q= [products]/[reactants]=[0.8]^2/[0.2][0.1]. Then plug everything else in and solve for ΔG.
- Sun Feb 14, 2021 11:29 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Phase Changes of Delta H and Delta S
- Replies: 3
- Views: 1782
Re: Phase Changes of Delta H and Delta S
when a substance changes from solid-> liquid-> gas, the delta H will be + and delta S will also be +.
when a substance changes from gas -> liquid-> solid, the delta H will be - and delta S will also be -.
when a substance changes from gas -> liquid-> solid, the delta H will be - and delta S will also be -.
- Sun Feb 14, 2021 11:18 pm
- Forum: Student Social/Study Group
- Topic: Spontaneous/Favorable
- Replies: 4
- Views: 226
Re: Spontaneous/Favorable
yes i think the two terms can be can be used interchangeably
- Sun Feb 07, 2021 10:21 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sapling #8 Week 4
- Replies: 3
- Views: 174
Sapling #8 Week 4
could someone pls explain how to approach this problem? I'm not quite sure where to even start. A 0.617 mol sample of SO2(g), initially at 298 K and 1.00 atm, is held at constant pressure while enough heat is applied to raise the temperature of the gas by 16.5 K. Calculate the amount of heat q requi...
- Sun Feb 07, 2021 10:18 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: heat capacity of a calorimeter
- Replies: 1
- Views: 109
heat capacity of a calorimeter
hi could someone explain what the heat capacity of a calorimeter is? when would we use this value? is it specific to different calorimeters?
- Sun Feb 07, 2021 10:14 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling #7, Week 4
- Replies: 3
- Views: 114
Sapling #7, Week 4
Hi could someone please explain how to do this problem? I'm not quite sure where to even start. An 80.0 g sample of a gas was heated from 25 ∘C to 225 ∘C. During this process, 346 J of work was done by the system and its internal energy increased by 6665 J. What is the specific heat of the gas?
- Sun Feb 07, 2021 10:11 pm
- Forum: Calculating Work of Expansion
- Topic: irreversible reactions
- Replies: 2
- Views: 170
irreversible reactions
hi, could someone pls explain why work reactions that happen at a constant external pressure are irreversible?
- Sun Feb 07, 2021 10:09 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: work and heat (positive or negative?)
- Replies: 3
- Views: 122
work and heat (positive or negative?)
hi, i was wondering if anyone had a good way to remember when work and heat are positive or negative. I kinda get confused often.
- Sun Jan 31, 2021 10:03 pm
- Forum: Calculating Work of Expansion
- Topic: Sapling week 4 #14
- Replies: 1
- Views: 130
Sapling week 4 #14
A sample of an ideal gas in a cylinder of volume 3.98 L at 298 K and 2.94 atm expands to 8.16 L by two different pathways. Path A is an isothermal, reversible expansion. Path B has two steps. In the first step, the gas is cooled at constant volume to 1.34 atm . In the second step, the gas is heated ...
- Sun Jan 31, 2021 6:01 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling #9 (week 3+4)
- Replies: 3
- Views: 162
Re: Sapling #9 (week 3+4)
one side must be negative to show that an equal amount of heat is being released from one substance and absorbed by the other.
- Sun Jan 31, 2021 5:58 pm
- Forum: Calculating Work of Expansion
- Topic: Work on the Surroundings
- Replies: 3
- Views: 116
Re: Work on the Surroundings
the equation for work is w=−PΔV and work is being done when w is negative. That means in order for work to be done ΔV must be a positive value. So we know work is being done with the volume increases in a chemical equation. You can figure this out by looking at the moles in the reactants versus the ...
- Sun Jan 31, 2021 5:56 pm
- Forum: Calculating Work of Expansion
- Topic: sapling week 4 #13
- Replies: 1
- Views: 60
sapling week 4 #13
At constant pressure, which of these systems do work on the surroundings? Why is 2A(g)+B(s)⟶3C(g) a correct answer? I understand the equation for work is w=−PΔV and work is being done when w is negative. But since the moles stay the same, doesn't that mean there is no volume change so w would equal ...
- Sun Jan 31, 2021 5:50 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling week 4 #12
- Replies: 1
- Views: 71
Sapling week 4 #12
At constant volume, the heat of combustion of a particular compound, compound A, is −3101.0 kJ/mol. When 1.147 g of compound A (molar mass =115.87 g/mol) is burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 6.169 ∘C. What is the heat capacity (calorime...
- Sun Jan 24, 2021 3:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference in Equilibrium
- Replies: 5
- Views: 256
Re: Difference in Equilibrium
An acid equilibrium is the equilibrium constant/chemical equilibrium of an acid.
- Sun Jan 24, 2021 3:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: Salt
- Replies: 19
- Views: 589
Re: Salt
Salt can be acidic, basic or neutral. If the salt contains the cation of a strong base, and the anion of a weak acid, then it will pull H+ from the water and make it basic. If the salt contains the anion of a strong acid, and the cation of a weak base, then it will pull OH- from the water and make i...
- Sun Jan 24, 2021 3:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: week 2 sapling #9/10
- Replies: 3
- Views: 106
week 2 sapling #9/10
for the sapling from this week, #9 and #10 focused on the relationship between pH and pKa. Can someone pls explain how the values of pH and pKa can affect the predominant species? Or maybe point to when Professor Lavelle went over it in the lecture/textbook.
- Fri Jan 22, 2021 1:42 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bromine standard state
- Replies: 4
- Views: 110
Bromine standard state
In today's lecture, Professor Lavelle pointed out that the standard state of Bromine is I2 and that it is a liquid. what does i2 mean? did he mean to say Br2 or is there some other meaning?
- Mon Jan 18, 2021 9:15 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: textbook 5I.11
- Replies: 2
- Views: 221
textbook 5I.11
A reaction vessel of volume 0.500 L at 700. K contains 1.20 mmol SO2(g), 0.50 mmol O2(g), and 0.10 mmol SO3(g). At 700. K, Kc 5 1.7 3 106 for the equilibrium 2 SO2(g) 1 O2(g) ∆ 2 SO3(g). (a) Calculate the reaction quotient Qc. I calculated Qc=(.1)^2/[(.5)(1.2)^2]=.0139, however the answer key says t...
- Sun Jan 17, 2021 10:45 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Temperature and Kc
- Replies: 5
- Views: 686
Re: Temperature and Kc
when a reaction is endothermic, meaning energy is required for the reactants to go to products, if a reaction is heated this will favor the forward reaction/the formation of products so Kc will increase. when a reaction is exothermic, meaning energy is released when the reactants go to products, if ...
- Sun Jan 17, 2021 10:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #10
- Replies: 8
- Views: 408
Re: Sapling Week 1 #10
To solve for the equilibrium constant, Kc, you do [products]/[reactants]. So for this it would be (2.28)^2/(0.463)
- Sun Jan 17, 2021 10:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: composition of the reaction mixture
- Replies: 2
- Views: 146
Re: composition of the reaction mixture
not necessarily, the composition of a reaction mixture is the reaction quotient, Q, which gives the concentration values for an expression that may not necessarily be at equilibrium yet.
- Sun Jan 17, 2021 10:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #10
- Replies: 4
- Views: 258
Re: Sapling #10
I think you need to factor the equation to be a quadratic so it will be Ax^2 + Bx + C = 0 and then use the quadratic formula x=[B +/- sqrt(B^2-4AC)]/2A. From this, you will get two answers and you need to eliminate the one that would give you a negative concentration value. Then you will have your x...
- Fri Jan 15, 2021 1:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When x is negligible in Equilibrium constant
- Replies: 34
- Views: 1326
Re: When x is negligible in Equilibrium constant
Hi!
I think Professor Lavelle said that in order for x to negligible, the value must be smaller that 10^-3 but to be safe under 10^-4.
I think Professor Lavelle said that in order for x to negligible, the value must be smaller that 10^-3 but to be safe under 10^-4.
- Mon Jan 11, 2021 12:21 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Coefficients for eq constant
- Replies: 9
- Views: 543
Re: Coefficients for eq constant
you would raise it to the power of that coefficient
- Mon Jan 11, 2021 12:18 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Temp
- Replies: 9
- Views: 384
Re: Change in Temp
yes when enthalpy is positive it's an endothermic reaction and when it is negative the reaction is exothermic
- Sun Jan 10, 2021 11:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 11
- Views: 606
Re: ICE Tables
you can use ICE tables to figure out the molar concentration of the products and reactants at equilibrium and the change in the molar concentration
- Sun Jan 10, 2021 11:31 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K on and reactant/product concentrations
- Replies: 8
- Views: 205
Q and K on and reactant/product concentrations
during lecture 2, Professor Lavelle said that if Q<K during a reaction, then [R]>[P] and the forward reaction is favored. however, isn't it possible for Q<K but for [P] to be greater than [R]?
- Sun Jan 10, 2021 11:14 pm
- Forum: Ideal Gases
- Topic: Inert Gases
- Replies: 7
- Views: 306
Re: Inert Gases
an inert gas is just a gas that does not react in the reaction
- Sun Dec 06, 2020 2:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 3
- Views: 217
Re: Final
There will be 30 questions on the final, each worth 6 points. I think quantum will be covered the most on the final since we spent the most time on it. The distribution is based on how long we spent on each topic.
- Sun Dec 06, 2020 2:56 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Sapling Week 10: #13 and #14
- Replies: 2
- Views: 158
Re: Sapling Week 10: #13 and #14
If a species is more predominant that means that is the majority in the solution. For an acidic solution, the predominant species will be charged and for a basic solution, the predominant species is neutral.
- Sun Dec 06, 2020 2:47 pm
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 5
- Views: 257
Re: Naming Coordination Compounds
first you list the ligand names in alphabetical order with (Greek Prefix), then the transition metal cation name (Roman Numeral) and then if there are anions, then you put the anion name, with a Greek Prefix and then the hydrate
- Sun Dec 06, 2020 2:41 pm
- Forum: Lewis Acids & Bases
- Topic: week 10 sapling #1
- Replies: 5
- Views: 323
week 10 sapling #1
In aqueous solution, classify these compounds as strong acids, weak acids, strong bases or weak bases.
How do you tell if an acid is strong or not?
How do you tell if an acid is strong or not?
- Sun Dec 06, 2020 2:37 pm
- Forum: Bronsted Acids & Bases
- Topic: bronsted vs. lewis acid
- Replies: 10
- Views: 354
bronsted vs. lewis acid
I was wondering if someone could explain the difference between a bronsted and a lewis acid. What's the difference between them? Is it possible for an acid to be both a bronsted and lewis acid?
- Sun Nov 29, 2020 11:20 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Shape
- Replies: 5
- Views: 349
Re: Seesaw Shape
The seesaw shape applies to when there are 5 areas of electron density. One area is a lone pair and the other 4 are bonds. When this happens, it leads to a seesaw structure.
- Sun Nov 29, 2020 11:17 am
- Forum: Hybridization
- Topic: Lecture #23
- Replies: 13
- Views: 622
Re: Lecture #23
Yes the electrons are delocalized and a pi bond is formed above and below the ring.
- Sun Nov 29, 2020 11:14 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: formation of coordination compounds
- Replies: 3
- Views: 109
formation of coordination compounds
In lecture #24, Professor Lavelle mentioned that to form salts, KCN or NaCl or NH3 would replace water's position in the ligand. Is there a reason water is so easily replaceable in a ligand solution?
- Sun Nov 29, 2020 11:06 am
- Forum: Hybridization
- Topic: hybridization orbitals
- Replies: 5
- Views: 215
Re: hybridization orbitals
it depends on its ground state electron configuration. Since C ends at 2p. the hybridization orbital is 2sp
- Sun Nov 29, 2020 10:58 am
- Forum: Sigma & Pi Bonds
- Topic: sapling #18
- Replies: 1
- Views: 442
sapling #18
Select the correct statement about the relative positions of the hydrogen atoms in the three structures. ->The hydrogen atoms of H2CCH2 and H2CCCCH2 lie in the same plane. The hydrogen atoms of H2CCCH2 and H2CCCCH2 lie in the same plane. The hydrogen atoms of H2CCH2 and H2CCCH2 lie in the same plane...
- Sun Nov 29, 2020 10:37 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelate Stability
- Replies: 3
- Views: 89
Re: Chelate Stability
i think multidentate ligands are more stable because they have more bonds so its more difficult to break but I'm not sure how easy it is to form multidentate ligands versus unidentate ligands
- Wed Nov 18, 2020 6:07 pm
- Forum: Trends in The Periodic Table
- Topic: Metallic Character
- Replies: 8
- Views: 697
Re: Metallic Character
Metallic character is greatest at the bottom left corner of the periodic table. The answer is in increasing order so P has the least metallic character and Na has the most. This follows and makes sense with the trend of metallic character across the periodic table.
- Wed Nov 18, 2020 5:23 pm
- Forum: Lewis Structures
- Topic: Identifying Radicals
- Replies: 4
- Views: 142
Re: Identifying Radicals
Hi!
Yes, all molecules that have an odd number of electrons are radicals.
Yes, all molecules that have an odd number of electrons are radicals.
- Wed Nov 18, 2020 5:19 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: 235
Re: Hydrogen Bonding
if a N, O or F atom has 2 lone pairs, then hypothetically yes it could form two hydrogen bonds, one for each lone pair.
- Sun Nov 15, 2020 9:46 pm
- Forum: Trends in The Periodic Table
- Topic: Ion Trends
- Replies: 28
- Views: 1237
Re: Ion Trends
I think you should know trends for ionization energy, electronegativity, atomic radius.
i'm not really sure about any others
i'm not really sure about any others
- Sun Nov 15, 2020 9:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Section 1D #25
- Replies: 2
- Views: 238
Re: Section 1D #25
The subshells possible for a certain shell is l=0,1,...n-1.
so for n=2, l=0, 1. However since for l=2 for d, the subshell 2d cannot exist.
Hope this helps!
so for n=2, l=0, 1. However since for l=2 for d, the subshell 2d cannot exist.
Hope this helps!
- Sun Nov 15, 2020 9:41 pm
- Forum: Resonance Structures
- Topic: bookwork 2C.15
- Replies: 2
- Views: 111
Re: bookwork 2C.15
The lewis structure that has more formal charges that are closer to zero are lower energy and more stable.
- Sun Nov 15, 2020 9:39 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Sapling 9
- Replies: 6
- Views: 389
Re: Oxidation Sapling 9
The sum of the oxidation numbers of the atoms in the perchlorate ion must equal the charge on the ion, -1. When oxygen is bonded to a nonmetal other than flourine, it has an oxidation number of -2. Because there are four oxygen atoms in the ion, chlorine must have an oxidation number of +7 to equal ...
- Sun Nov 15, 2020 9:26 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: polar vs nonpolar
- Replies: 3
- Views: 157
Re: polar vs nonpolar
If a molecule is polar, that means the charge distribution will be unequal. For example, in the molecule HF it would be polar because F is much more electronegative than H and therefore will have a stronger pull on the electrons. Making the F side of the molecule slightly more negative than the H si...
- Sun Nov 15, 2020 3:11 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: Sapling question Hydrogen Bonding
- Replies: 1
- Views: 131
Re: Sapling question Hydrogen Bonding
Hey! In order for there to be hydrogen bonding, there needs to either be a Hydrogen bonded to a highly electronegative atom (N, O, F) or a lone pair of a highly electronegative atom (N, O, F). So for this problem, theoretically there are 8 sites where hydrogen bonds can be formed with this molecule....
- Sun Nov 08, 2020 9:54 pm
- Forum: Einstein Equation
- Topic: E=pc vs E=hv
- Replies: 15
- Views: 674
Re: E=pc vs E=hv
Hey!
My understanding is that E=hv is only used for light/photons. However, E=pc is used for these that have mass, like electrons.
My understanding is that E=hv is only used for light/photons. However, E=pc is used for these that have mass, like electrons.
- Sun Nov 08, 2020 9:51 pm
- Forum: Lewis Structures
- Topic: Valence Shell electrons
- Replies: 2
- Views: 158
Valence Shell electrons
So my understanding is that valence shells must have 8 electrons. And these are represented by the s2p6. However, what does the d and f orbital represent then? Do these also fill valence shells?
- Sun Nov 08, 2020 9:48 pm
- Forum: Lewis Structures
- Topic: nitrate lewis structure
- Replies: 7
- Views: 963
Re: nitrate lewis structure
I think it has to do with formal charge. If two of the oxygen had a double bond, then the nitrogen would have 5 bonds which is not very stable.
- Sun Nov 08, 2020 9:39 pm
- Forum: Lewis Structures
- Topic: Lewis acids and bases
- Replies: 10
- Views: 249
Lewis acids and bases
how can we tell the difference between a molecule that is an acid or a base? do they react differently in chemical reactions?
- Sun Nov 08, 2020 9:05 pm
- Forum: Student Social/Study Group
- Topic: Midterm 2
- Replies: 28
- Views: 1002
Re: Midterm 2
I would say to do the textbook homework problems and attend the step up learning sessions. Don't wait until the last minute to do these questions, you should try to do these along with the lectures that pertain to the textbook problems. For me, it helps to reinforce my understanding of what Prof.Lav...
- Fri Oct 30, 2020 5:47 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Sapling homework
- Replies: 2
- Views: 185
Re: Sapling homework
The question is basically asking how many electrons could have these criteria. so for the first one, n=3 The 3 shell has 3s, 3p, 3d and in each of these subshells they can contain 2, 6, 10 electrons respectively. Then add them together and the answer is 18. For the second question, n=4, l=2 This is ...
- Fri Oct 30, 2020 5:40 pm
- Forum: Trends in The Periodic Table
- Topic: ionization trend
- Replies: 3
- Views: 163
Re: ionization trend
Hi Brett, I'm not completely sure but my understanding is that in order to conduct electricity, electrons need to be able to to be transferred relatively easily from atom to atom as free electrons. And when the ionization energy for an atom is low, this means that the energy needed to remove an elec...
- Fri Oct 30, 2020 5:36 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Finding Electrons with Quantum Numbers
- Replies: 3
- Views: 205
Re: Finding Electrons with Quantum Numbers
Hi Quinton, So for the first question since n=4 AND l=2, this is referring to electrons that are in the 4d subshell only. The value of l for the electrons from the 4s or 4p subshells do not equal 2 so they don't apply to this question. I think the answer should be 10. For the second question, when n...
- Fri Oct 30, 2020 4:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: SAPLING #20
- Replies: 4
- Views: 143
SAPLING #20
Identify the reasons why oxygen has a lower first ionization energy than both nitrogen and flourine.
So I understand why oxygen has a lower first ionization energy than oxygen but can someone explain why for nitrogen?
So I understand why oxygen has a lower first ionization energy than oxygen but can someone explain why for nitrogen?
- Tue Oct 27, 2020 1:30 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: atomic spectroscopy vs. molecular spectroscopy
- Replies: 2
- Views: 80
atomic spectroscopy vs. molecular spectroscopy
can someone explain the point on the Unit 2: Outline that says"with respect to electron transitions that give rise to a UV or visible spectrum: understand the difference between electronic transitions in atomic orbitals and electronic transitions in molecular orbitals" or if u could point ...
- Fri Oct 23, 2020 4:38 pm
- Forum: DeBroglie Equation
- Topic: Sapling Question 22
- Replies: 3
- Views: 190
Re: Sapling Question 22
The reason you must use de Broglie's equation for this problem is because it is talking about an electron. The equation c=wv only applies to photons since c is the speed of light. When you use that equation for an electron, your answer will be incorrect. However, de Broglie's equation can be used fo...
- Fri Oct 23, 2020 4:34 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Writing Electron Configuration
- Replies: 2
- Views: 59
Re: Writing Electron Configuration
For an excited state electron configuration, the electrons won't necessarily be in the "correct" (groundstate) order. For example Carbon has 6 electrons. A ground state configuration would be 1s2, 2s2, 3s2. But if one of the electrons were to be excited, then the excited-state electron con...
- Fri Oct 23, 2020 4:30 pm
- Forum: *Shrodinger Equation
- Topic: Clarification Needed..
- Replies: 3
- Views: 130
Re: Clarification Needed..
I asked my TA about this and I think he was just explaining how they got the equation but for this class we won't necessarily need to know how to derive it. I think the wave is to represent the probability that you will find an electron there. So at the peaks, it has the greatest probability and whe...
- Fri Oct 23, 2020 4:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Energy Levels in the same Shell
- Replies: 2
- Views: 135
Re: Energy Levels in the same Shell
Hey! I'm not 100% sure why it is that they have lower energy but I don't think we need to know why for now, just know that the order of increasing orbitals is s, p, d, f.
- Fri Oct 23, 2020 4:22 pm
- Forum: Properties of Light
- Topic: Sapling Homework week 2 problem 5
- Replies: 11
- Views: 458
Re: Sapling Homework week 2 problem 5
Hey! I think you are doing it correct but you just need to convert from cm to m before you find Energy (J).
- Fri Oct 23, 2020 4:12 pm
- Forum: Trends in The Periodic Table
- Topic: Shielding Effect
- Replies: 2
- Views: 81
Re: Shielding Effect
Hey! So I don't think the electrons are necessarily lined up right next to each other. We never know the exact location of the electron, we only know that they are located in their orbitals which are high probability areas, like the s-orbital(sphere). Even though we don't know the exact location, th...
- Fri Oct 23, 2020 4:04 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: 1B.9 Question
- Replies: 2
- Views: 161
Re: 1B.9 Question
I solved it by using the equation E=(hc)/wavelength to get 4.73 x 10^-19 Joules/photon. Then in order to get the # of photons, I divided 64J by 4.73 x 10^-19 J/photon to get the number of individual protons (1.35 x 10^20 photons). Then to convert the photons to moles use Avogadro's number to get 2.2...
- Fri Oct 16, 2020 2:42 pm
- Forum: Properties of Electrons
- Topic: calculating the frequency of Light
- Replies: 4
- Views: 79
Re: calculating the frequency of Light
Hey! I posted a reply to this in Lec 7. Question [ENDORESED] but I've attached it below. I hope it helps! The negative sign simply is to show that this is the amount of energy LOST by the electron. We changed it to a positive sign to show the amount of energy being ABSORBED by the photon or turned i...
- Fri Oct 16, 2020 2:39 pm
- Forum: Properties of Electrons
- Topic: calculating the frequency of light
- Replies: 4
- Views: 167
Re: calculating the frequency of light
The -1/16 is denoting the energy for when the n=4. In the equation, E = (hR)/n^2, so when n=4, it would be (-1/16)*hR. The -1/4 is showing when n=2.
- Fri Oct 16, 2020 2:37 pm
- Forum: SI Units, Unit Conversions
- Topic: 10^?
- Replies: 2
- Views: 196
Re: 10^?
i think the easiest way would just be to plug the equation, as it's written, into your calculator! If you are having trouble figuring out which 10^?, then I would recommend switching to scientific notation rather than flo. It would probably be easiest just to look up how to do this for your specific...
- Fri Oct 16, 2020 2:33 pm
- Forum: Properties of Electrons
- Topic: Electron Transition
- Replies: 7
- Views: 247
Re: Electron Transition
electron transition refers to when an electron changes energy levels in an atom/molecule. For example an electron can be excited during a photoelectric experiment and jump from energy level n=1 to n=3
- Fri Oct 16, 2020 2:12 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Lecture 7 Question [ENDORSED]
- Replies: 4
- Views: 243
Re: Lecture 7 Question [ENDORSED]
The negative sign simply is to show that this is the amount of energy LOST by the electron. We changed it to a positive sign to show the amount of energy being ABSORBED by the photon or turned into light. This works because according to the conservation of energy, energy cannot be created or destroy...
- Fri Oct 16, 2020 2:06 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectroscopy N?
- Replies: 3
- Views: 182
Re: Atomic Spectroscopy N?
I think to find the change in energy, you do the final energy - initial energy.
- Fri Oct 09, 2020 3:07 pm
- Forum: Limiting Reactant Calculations
- Topic: Actual yield
- Replies: 20
- Views: 671
Re: Actual yield
You should be able to calculate the theoretical yield. As for the actual yield, I think this is usually given to you or maybe as a percentage of the theoretical yield, so that you would be able to solve for the actual yield.
- Fri Oct 09, 2020 3:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Exam Regulations
- Replies: 7
- Views: 180
Re: Exam Regulations
I think they will all be closed book.
- Fri Oct 09, 2020 3:04 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: HW E.15
- Replies: 4
- Views: 106
HW E.15
E.15 The molar mass of the metal hydroxide M(OH)2 is 74.10g*mol -1. What is the molar mass of the sulfide of this metal?
What does it mean the sulfide of this metal? Am I supposed to convert it to something else?
What does it mean the sulfide of this metal? Am I supposed to convert it to something else?
- Fri Oct 09, 2020 3:01 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Petition to Bring Music Back To Lectures [ENDORSED]
- Replies: 34
- Views: 1197
Re: Petition to Bring Music to Back To Lectures [ENDORSED]
Yes! I agree! We need the music back! It helps to make it feel like a real lecture in the classroom
- Fri Oct 09, 2020 2:59 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.13
- Replies: 3
- Views: 216
Re: G.13
So in the first solution, there are 0.20 moles of NH4NO3. When the florist dilutes it by adding 3.0L of water, the molarity of the solution is .20 mol/ 4 L = .05 Molarity. From there, the florist pours 100ml, or 0.1 L, of this diluted solution into each plant. So the number of moles of NH4NO3 being ...
- Fri Oct 09, 2020 2:46 pm
- Forum: Properties of Light
- Topic: Amplitude and Velocity Relationship
- Replies: 3
- Views: 93
Re: Amplitude and Velocity Relationship
My understanding is that amplitude does not affect wave velocity. However, amplitude has more to do with the energy or intensity of the light? I'm not 100% sure though, anyone can feel free to correct me.
- Thu Oct 08, 2020 5:48 pm
- Forum: DeBroglie Equation
- Topic: Question about post-module assessment
- Replies: 5
- Views: 328
Re: Question about post-module assessment
hey! could you be more specific about where this problem is from?