Search found 50 matches

Mon Mar 19, 2018 1:21 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: heat capacity
Replies: 1
Views: 367

heat capacity

Are there any monatomic ideal gases that don't use the heat capacity constants 5/2R and 3/2R for constant pressure and constant volume
Mon Mar 19, 2018 1:12 am
Forum: Balancing Redox Reactions
Topic: periodic trends
Replies: 3
Views: 337

periodic trends

what are the trends for reducing and oxidizing power on the periodic table
Mon Mar 19, 2018 1:12 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: kinetic data
Replies: 2
Views: 329

kinetic data

how do you use kinetic data to distinguish between different reaction mechanisms?
Mon Mar 19, 2018 1:08 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: equation involving enthalpy and entropy
Replies: 1
Views: 543

equation involving enthalpy and entropy

are there any types of molecules in a chemical equation that you would exclude when calculating reaction enthalpy or entropy?
Mon Mar 19, 2018 1:06 am
Forum: Calculating Work of Expansion
Topic: reversible and irreversible expansion
Replies: 3
Views: 547

reversible and irreversible expansion

if a problem doesn't make it clear if reversible or irreversible expansion is occurring, how do you know which equation to use for work?
Sun Mar 11, 2018 1:49 am
Forum: General Rate Laws
Topic: graphs
Replies: 8
Views: 423

graphs

besides knowing what the parts of the derived equations stand for like the slope and such, do we need to know how to draw the graphs for zero order, first order, and second order reactions?
Sun Mar 11, 2018 1:47 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: units
Replies: 4
Views: 427

units

on the final, will we only need to know units in mol, L, and s or will Kpa show up because it was in the textbook
Sun Mar 11, 2018 12:42 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: terms
Replies: 1
Views: 198

terms

what do the terms labile, nonlabile, and inert mean and how are they significant to calculating gibbs free energy
Sun Mar 11, 2018 12:40 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: concept question
Replies: 2
Views: 289

concept question

why does gibbs free energy decreases more sharply with temperature for the gas phase of a substance than for the liquid phase?
Sun Mar 11, 2018 12:20 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: residual entropy
Replies: 2
Views: 459

residual entropy

what's residual entropy and do we need to know and understand the concept for the final?
Sun Mar 11, 2018 12:18 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: entropy of vaporization
Replies: 1
Views: 336

entropy of vaporization

To find the entropy of vaporization, why do we have to separate it into 3 steps as in heat the liquid to its boiling point, allow it to vaporize, then cool the vapor?
Sun Mar 11, 2018 12:16 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: change in entropy
Replies: 1
Views: 163

change in entropy

when calculating a change in entropy, does it matter if it is through a reversible or irreversible path?
Sat Mar 10, 2018 11:52 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: enthalpy of sublimation
Replies: 5
Views: 485

enthalpy of sublimation

Do we need to know the enthalpy of sublimation for the final?
Sat Mar 10, 2018 11:46 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: change in internal energy
Replies: 3
Views: 330

change in internal energy

for examples involving calculating energy changes when heating an ideal gas, why do you have to separate the problem into two steps, step 1 being heating at constant volume to the final temperature, and step 2 being allowing the gas to expand isothermally?
Sat Mar 10, 2018 11:25 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: molar heat capacity
Replies: 1
Views: 154

molar heat capacity

why is the molar heat capacity of an ideal gas at constant pressure greater than that at constant volume?
Sat Mar 10, 2018 11:16 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: equipartition theorem
Replies: 1
Views: 152

equipartition theorem

Do we need to know anything about the equipartition theorem?
Sat Mar 10, 2018 11:14 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: state functions
Replies: 4
Views: 525

state functions

why are heat and work not state functions?
Sat Mar 10, 2018 11:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: calorimeter examples
Replies: 1
Views: 143

calorimeter examples

can someone provide some examples where we would have to relate the heat lost or gained by a reaction to the heat gained or lost by the calorimeter? or example for when we would use the q=-qcal equation
Sat Mar 10, 2018 10:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: heat capacity [ENDORSED]
Replies: 1
Views: 154

heat capacity[ENDORSED]

how is heat capacity an extensive property and what are some other examples of extensive properties in thermodynamics?
Sat Mar 10, 2018 10:52 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: adiabatic and diathermic
Replies: 1
Views: 175

adiabatic and diathermic

how are adiabatic and diathermic walls significant to the measurement of heat and what is the difference between the two?
Sat Mar 10, 2018 10:36 pm
Forum: Calculating Work of Expansion
Topic: internal energy [ENDORSED]
Replies: 1
Views: 143

internal energy[ENDORSED]

In what cases does the internal energy remain constant between the initial and final state and in what cases is the internal energy at 0?
Sat Mar 10, 2018 10:30 pm
Forum: Calculating Work of Expansion
Topic: reversible expansion [ENDORSED]
Replies: 1
Views: 144

reversible expansion[ENDORSED]

why can a system do more work in a reversible expansion versus irreversible expansion?
Sat Mar 10, 2018 10:18 pm
Forum: Calculating Work of Expansion
Topic: different types of work
Replies: 4
Views: 239

different types of work

Do we have to know the different types of work on the final like extension, raising a weight, and surface expansion?
Sat Mar 10, 2018 9:50 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: types of systems
Replies: 3
Views: 445

types of systems

What are some of the most commonly referenced examples of open, closed, and isolated systems?
Sun Feb 11, 2018 11:31 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: cis vs trans [ENDORSED]
Replies: 4
Views: 399

cis vs trans[ENDORSED]

can someone provide an example of how cis and trans orientations are involved in entropy?
Sun Feb 11, 2018 11:28 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: troutons rule
Replies: 3
Views: 264

troutons rule

Do we need to know troutons rule at all?
Sun Feb 11, 2018 11:17 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Second Law
Replies: 2
Views: 177

Re: Second Law

the equation wasn't specifically used in many examples as only example 9.3 used the equation directly, but the equation is derived to attain the equations for entropy change when there's a change in temperature with constant volume or pressure, and for entropy change of an ideal gas when it expands ...
Tue Jan 30, 2018 5:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: heat capacities
Replies: 5
Views: 377

heat capacities

in problems where you need to find the final temperature using the equation, heat lost by ice=- heat gained by water
how do you know whether to use the heat capacity of the ice or the water in the equation?
Tue Jan 30, 2018 5:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpies
Replies: 3
Views: 235

bond enthalpies

Can someone provide an example of how to estimate the enthalpy of a reaction using mean bond enthalpies and explain the difference between this calculation and when given the bond enthalpies of the products, but not the reactants?
Tue Jan 30, 2018 5:34 pm
Forum: Phase Changes & Related Calculations
Topic: hw problem #109
Replies: 1
Views: 129

hw problem #109

I don't understand the concept of how density is involved in solving for heat and why are the dimensions multiplied by the density?
Also, how do you find the mass of water?
Sun Dec 10, 2017 4:01 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: example problem for Ka and Kb [ENDORSED]
Replies: 1
Views: 293

example problem for Ka and Kb[ENDORSED]

If you're given the value for pKa, but the compound you're given is a base, then how do you find Kb?
Sun Dec 10, 2017 3:57 pm
Forum: Amphoteric Compounds
Topic: amphiprotic vs. amphoteric [ENDORSED]
Replies: 2
Views: 573

amphiprotic vs. amphoteric[ENDORSED]

according to the textbook definition, amphiprotic specifically pertains to water molecules, but I noticed In the homework problems that amphiprotic referred to other compounds as well acting as both proton donors and acceptors; What's the main difference between amphiprotic and amphoteric and is amp...
Sat Dec 02, 2017 3:06 pm
Forum: Naming
Topic: naming compounds [ENDORSED]
Replies: 3
Views: 300

naming compounds[ENDORSED]

Which part of the compound when naming it is the lewis acid? Is it the central metal atom? Also, when naming compounds with polydentates, do we have to know more than what is listed in table 17.4 like other than en, dien, and edta?
Sat Dec 02, 2017 3:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: coordination number/polydentates [ENDORSED]
Replies: 1
Views: 177

coordination number/polydentates[ENDORSED]

How do polydentates factor into figuring out the coordination number of a compound? Can someone provide an example of that? Also for identifying polydentates, do we only need to memorize table 17.4 for the final or should we know more than the ones listed in the table?
Tue Nov 28, 2017 6:07 pm
Forum: Hybridization
Topic: Ch 4 Question 75
Replies: 3
Views: 276

Re: Ch 4 Question 75

to determine the polarity of a molecule, you must first draw the lewis structure of the molecule and in this case, carbon and oxygen are the two central atoms. Carbon has 3 hydrogens and an oxygen attached to it while oxygen has 1 hydrogen and 1 carbon atom attached to it. The oxygen atom has 2 lone...
Tue Nov 28, 2017 5:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: chapter 4
Replies: 1
Views: 164

Re: chapter 4

According to the valence-bond theory, bonds form when unpaired electrons in valence-shell atomic orbitals pair; the atomic orbitals overlap end to end to form sigma bonds or side by side to form pi bonds between atoms in a molecule. In addition, for the structure of a molecule, hybrid orbitals are c...
Thu Nov 16, 2017 2:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 5
Views: 416

Re: Lone Pairs

The first step to determining and drawing molecular shape is drawing the lowest energy lewis structure of the molecule to determine where the lone pairs go. Then you would go on to determine the shape of the molecule, the bond angles, and hybridization.
Thu Nov 16, 2017 2:45 pm
Forum: Hybridization
Topic: 2 regions of electron density
Replies: 4
Views: 352

2 regions of electron density

Why can't molecules with two regions of electron density have a bent shape?
Thu Nov 16, 2017 2:39 pm
Forum: Hybridization
Topic: Difference between sigma and pi bonds?
Replies: 6
Views: 1262

Re: Difference between sigma and pi bonds?

sigma and pi bonds are associated with the electron density and how the electrons interact with each other. A sigma bond is formed by the pairing of electron spins in two atomic orbitals on neighboring atoms. sigma bonds are cylindrically symmetrical and they contribute towards an overlap or merging...
Thu Nov 16, 2017 2:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar or Non-polar
Replies: 3
Views: 1574

Re: Polar or Non-polar

CCl2 would be predicted to be a linear (bond angle 180º) molecule, and because the two chlorine atoms attached are both of the same electronegativity, the resulting net dipole would be zero because the Cl electronegativity vectors cancel each other out.
Sun Nov 12, 2017 3:27 pm
Forum: Lewis Structures
Topic: atomic structure of HOCO
Replies: 8
Views: 541

atomic structure of HOCO

Why is the hydrogen not attached to the carbon in HOCO? Usually when bonded to hydrogens and oxygens, carbon is the main central atom, so I was confused why the correct structure has the hydrogen attached to the oxygen atom and not the carbon atom?
Sun Nov 12, 2017 3:21 pm
Forum: Lewis Structures
Topic: Midterm Question CH3SH
Replies: 5
Views: 484

Re: Midterm Question CH3SH

the reasoning behind it is because carbon is slightly less electronegative than sulfur; thus, carbon would be the main central atom with 3 hydrogens surrounding it as carbon atoms are larger than hydrogens which will most likely never be the central atom as they are small, highly electronegative ato...
Sun Nov 12, 2017 3:01 pm
Forum: Lewis Structures
Topic: 3.67 a.
Replies: 2
Views: 189

Re: 3.67 a.

The radical goes on the chlorine atom because it is less electronegative than oxygen so the unpaired electron will be attached to the chlorine atom and because most of the time, you have to satisfy the octet rule for Oxygen first due to its high electronegativity.
Sun Nov 12, 2017 2:48 pm
Forum: Lewis Structures
Topic: Expanded Valence Shell
Replies: 2
Views: 191

Re: Expanded Valence Shell

the larger the central atom, the larger the number of electrons that can surround it and expanded valence shells occur most commonly when the central atom is bonded to small electronegative atoms like F, Cl, and O. The greatest I can think of is iodine heptafluoride which has 7 bonds, but expanded v...
Sat Oct 28, 2017 3:03 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Determining valence electrons for d-block elements [ENDORSED]
Replies: 3
Views: 4620

Re: Determining valence electrons for d-block elements[ENDORSED]

the number of valence electrons in d-block elements is most often equal to their group number which is equal to the number of electrons in the "valence shell." for example, scandium metal's electrons per shell are 2,8,9,2 and its outer shell has only 2 electrons, so the valence electron co...
Sat Oct 28, 2017 2:40 pm
Forum: *Particle in a Box
Topic: particle in a box example
Replies: 1
Views: 458

particle in a box example

Can someone help me how to solve an example like this where you're given the info to treat a hydrogen atom as a one-dimensional box of length 120. pm containing an electron and predict the wavelength of the radiation emitted when the electron falls to the lowest energy level from the next higher ene...
Sun Oct 22, 2017 5:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: heisenberg post-module question 21
Replies: 1
Views: 210

heisenberg post-module question 21

The electron is not confined to the nucleus and we now know that the size of an atom is determined by its electrons outside of the nucleus. For hydrogen its measured atomic diameter is 145,000 times its nuclear diameter of 1.7 x 10-15 m. In other words make the (correct) assumption that the electron...
Sun Oct 22, 2017 5:07 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: post-module question #22
Replies: 2
Views: 223

post-module question #22

Use the above uncertainty in velocity (correct model) to calculate the electron's uncertainty in kinetic energy. Then calculate the uncertainty in kinetic energy per mole of electrons (that is, per mole of hydrogen atoms). Comment on your value. I don't understand how to calculate the uncertainty in...
Thu Oct 12, 2017 4:41 pm
Forum: Photoelectric Effect
Topic: Photoelectric effect example problem [ENDORSED]
Replies: 2
Views: 275

Photoelectric effect example problem[ENDORSED]

How do you solve a problem where the given information includes that an electron is ejected from a metal due to the photoelectric effect with a velocity in km per second and the work function is given, but you're supposed to calculate the wavelength of the photon absorbed.
Thu Oct 12, 2017 4:31 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 3
Views: 360

Re: Wave Properties of Electrons

The wave properties of electrons were discovered through the results of the photoelectric effect and diffraction experiments. Not only did they discover the wave-like properties of electrons, but they also discovered that electromagnetic radiation is particlelike and wavelike. This led towards the a...

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