Search found 72 matches

by manasa933
Thu Mar 15, 2018 6:21 pm
Forum: Phase Changes & Related Calculations
Topic: 9.19
Replies: 1
Views: 156

Re: 9.19

The three steps are required as water must be heated to 100 C to vaporize, and then it must be vaporized. Since, they're asking for the final vapor to be at 85 C you need to add another entropy change from the vapor at 100 C to 85 C. All this is required since water doesn't vaporize at a 100 degrees...
by manasa933
Thu Mar 15, 2018 6:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15.a
Replies: 1
Views: 88

14.15.a

When writing the cell diagram, shouldn't Br- be written before AgBr as the reaction at the anode is going from Br- to AgBr?
by manasa933
Thu Mar 15, 2018 4:31 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.93.a
Replies: 1
Views: 64

14.93.a

If you were to construct a concentration cell in which one half-cell contains 1.0 m CrCl3 and the other half-cell contains 0.0010 m CrCl3, and both electrodes were chromium, at which electrode would reduction take place spontaneously? Why does reduction take place at the electrode with the higher co...
by manasa933
Tue Mar 06, 2018 1:29 pm
Forum: First Order Reactions
Topic: 15.37
Replies: 3
Views: 99

15.37

In part (c), the mass is taken as the concentration because the vessel is sealed. But why is this true?
by manasa933
Tue Mar 06, 2018 12:00 pm
Forum: General Rate Laws
Topic: Rate of formation/consumption
Replies: 3
Views: 73

Rate of formation/consumption

When calculating the rate of formation/consumption, do we take the concentrations of the reactants or products or both?
by manasa933
Tue Mar 06, 2018 11:53 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: reaction mechanism
Replies: 1
Views: 60

reaction mechanism

Will we be told if an elementary step is a fast or slow one? And do we always assume pre-equilibrium conditions?
by manasa933
Tue Mar 06, 2018 11:01 am
Forum: General Rate Laws
Topic: Molecularity vs Order
Replies: 1
Views: 60

Molecularity vs Order

Is the molecularity and order the same for elementary reactions and the overall reaction? If not, what's the difference?
by manasa933
Tue Feb 27, 2018 7:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram order
Replies: 4
Views: 109

Cell diagram order

In a cell diagram, is there any specific order in which we write the redox couple in the same phase?
by manasa933
Tue Feb 27, 2018 7:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell potential
Replies: 5
Views: 140

Cell potential

When trying to figure whether a redox couple forms the anode or cathode, do we first like for sign or whether electrons are consumed or given off?

There were some examples in the textbook in which, though the sign was negative, the redox couple formed the cathode.
by manasa933
Tue Feb 27, 2018 7:14 pm
Forum: General Rate Laws
Topic: Orders and units
Replies: 3
Views: 98

Re: Orders and units

First order is:
k=rate/[A]
Second order reaction:
k=rate/[A]^2
Third order reaction:
k=rate/[A]^3

We measure concentration as mol/L, hence, for reactions of a different order it is (mol/L)^order.
by manasa933
Mon Feb 19, 2018 12:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.23A
Replies: 1
Views: 67

Re: 14.23A

I'm not really sure why but my TA said that we don't flip potentials because the redox couple is the same.
by manasa933
Mon Feb 19, 2018 12:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: oxi/red potentials
Replies: 1
Views: 51

oxi/red potentials

Suppose two redox couples have negative potentials, is there any case in which the more negative one can undergo reduction?
by manasa933
Mon Feb 19, 2018 12:19 pm
Forum: Balancing Redox Reactions
Topic: Balancing H
Replies: 2
Views: 81

Balancing H

In basic solutions, after balancing O, do we balance hydrogen by adding an equal number of hydrogens to the other side by adding water or do we add an equal number of H20 to the number of hydrogens?

ex: if there are 6H on the right, do we add 3H to the left or 6H20?
by manasa933
Mon Feb 12, 2018 5:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.99 (a)
Replies: 1
Views: 94

11.99 (a)

Why is it that in this problem we take 1/2 of delta G as the answer for the production of 1 mole of X rather than dividing K by 1/2?
by manasa933
Mon Feb 12, 2018 11:28 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Molar entropies
Replies: 5
Views: 319

Re: Molar entropies

They are molar entropies taken under standard conditions with pure forms of the substance. (1 bar and usually, 298K unless specified otherwise)
by manasa933
Mon Feb 12, 2018 11:26 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 9.38 (d)
Replies: 1
Views: 72

9.38 (d)

How are the products of the reaction: 4KClO3(s) ---> 3KClO4(s) + KCL(s), more ordered than the reactants?
by manasa933
Mon Feb 12, 2018 11:25 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.31
Replies: 1
Views: 62

9.31

Why do we take C(v) and not C(p) when the volume is changing?
by manasa933
Sun Feb 11, 2018 8:07 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Which is more stable: Fe3O4 or Fe2O3?
Replies: 2
Views: 93

Which is more stable: Fe3O4 or Fe2O3?

The solutions manual says Fe2O3 is more stable, but since the G of formation is more negative for Fe3O4 , isn't it more stable? Also since Fe3O4 is a larger compound, shouldn't it be more stable?
by manasa933
Tue Feb 06, 2018 11:09 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Tendency of processes
Replies: 2
Views: 77

Tendency of processes

Do reactions/processes tend to go towards a lower gibbs free energy or a higher energy and why?
by manasa933
Tue Feb 06, 2018 11:04 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free energy
Replies: 1
Views: 66

Gibbs Free energy

In the textbook it says the Gibbs free energy of the solid phase lies the lowest. If the entropy of a gas is the highest (compared to liquids and solids), shouldn't the free energy of the gas be the lowest at a certain temperature?
by manasa933
Tue Feb 06, 2018 11:00 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Boltzmann Equation
Replies: 2
Views: 79

Re: Boltzmann Equation

Kb is equal to 1.381 x 10^-23 J/K
by manasa933
Tue Feb 06, 2018 10:58 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs energy for gas and liquid phase
Replies: 1
Views: 76

Gibbs energy for gas and liquid phase

Why does the Gibbs free energy decrease more sharply with temperature for a gas than for the liquid?
by manasa933
Fri Feb 02, 2018 3:45 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: Residual Entropy [ENDORSED]
Replies: 2
Views: 130

Residual Entropy [ENDORSED]

Why is it that molecules with a greater dipole moment have smaller residual entropies?
by manasa933
Fri Feb 02, 2018 3:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz 1, #1
Replies: 2
Views: 137

Quiz 1, #1

On quiz 1, question 1, there was a question like "Do you expect there to be a difference in your answers in part 'a' and 'b'? Why?" What's the reason that there won't be a difference?
by manasa933
Fri Feb 02, 2018 3:06 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Change in vol and temp
Replies: 2
Views: 69

Change in vol and temp

What formula (for entropy) do we use if there is a change in both volume and temperature?
by manasa933
Fri Feb 02, 2018 2:54 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Free expansion
Replies: 2
Views: 114

Free expansion

If q=0, and work is different in two conditions (one of which is free expansion and the other one isn't), then U will be different in both cases. Isn't this against the statement that U is a state function?
by manasa933
Fri Feb 02, 2018 2:40 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Nonspontaneous processes
Replies: 2
Views: 125

Nonspontaneous processes

Can non-spontaneous processes only be done by work or also heat?
by manasa933
Wed Jan 24, 2018 5:01 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 2
Views: 118

Heat capacity

What exactly does heat capacity tell you? (apart what the formula states) like, what does a large heat capacity suggest?
by manasa933
Wed Jan 24, 2018 2:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.117 [ENDORSED]
Replies: 1
Views: 82

8.117 [ENDORSED]

The net production of moles of gas(delta n) is 2/3 moles in the solutions manual, but wouldn't it only be 2?
by manasa933
Wed Jan 24, 2018 10:45 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.63
Replies: 4
Views: 145

Re: 8.63

The enthalpy of formation of liquid in it's liquid state is -285.85 kJ/mol
by manasa933
Fri Jan 19, 2018 8:36 pm
Forum: Phase Changes & Related Calculations
Topic: Closed Systems [ENDORSED]
Replies: 8
Views: 412

Closed Systems [ENDORSED]

What's a method to increase the internal energy of a closed system?
by manasa933
Fri Jan 19, 2018 6:50 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity of dilute solutions [ENDORSED]
Replies: 1
Views: 82

Heat capacity of dilute solutions [ENDORSED]

The textbook says 'the specific heat capacity' of dilute solutions is taken to be the same as the pure solvent'. Why isn't this true for molar heat capacity?
by manasa933
Fri Jan 19, 2018 6:47 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: C(v) and C(p)
Replies: 3
Views: 110

Re: C(v) and C(p)

Do you mean Cv is equal to dU?
by manasa933
Fri Jan 19, 2018 6:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Diathermic walls
Replies: 3
Views: 159

Diathermic walls

Can someone explain what diathermic walls are? I don't understand the definition in the textbook.
by manasa933
Fri Jan 19, 2018 10:29 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Gas molar heat capacity [ENDORSED]
Replies: 4
Views: 215

Re: Gas molar heat capacity [ENDORSED]

One is under constant volume, and the other under constant pressure.
by manasa933
Fri Jan 19, 2018 10:28 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: C(v) and C(p)
Replies: 3
Views: 110

C(v) and C(p)

Why is that C(under constant pressure) is greater than C(under constant volume) for gases and not liquids and solids?
by manasa933
Sat Dec 09, 2017 5:41 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Effect of water
Replies: 2
Views: 228

Effect of water

Does removing/adding water(or anything in the 'l' or 'aq' phase) or increasing the pressure of water (or anything in the 'l' or 'aq' phase) have any effect on which direction the reaction will proceed?
by manasa933
Thu Dec 07, 2017 6:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Pi bond
Replies: 3
Views: 178

Pi bond

According to the VSEPR theory, does a pi bond have localized or de-localized electrons, and why?
by manasa933
Tue Dec 05, 2017 7:18 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Electron withdrawing power
Replies: 1
Views: 97

Electron withdrawing power

In a carboxylic acid, which Oxygen has the electron withdrawing power?
by manasa933
Tue Dec 05, 2017 6:40 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Acid and Base equations
Replies: 2
Views: 131

Re: Acid and Base equations

The ionic equation includes all ions involved in the reaction and the net ionic equation is what you get after cancelling on both sides of the ionic equation
by manasa933
Tue Dec 05, 2017 5:30 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: CH3COOH
Replies: 3
Views: 292

Re: CH3COOH

It will only ever donate the last H because this is the only acidic hydrogen present in the compound.
by manasa933
Thu Nov 30, 2017 8:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: P4
Replies: 2
Views: 170

P4

Is p4 polar or non-polar, and why?
by manasa933
Thu Nov 30, 2017 5:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Effect of pressure [ENDORSED]
Replies: 1
Views: 123

Effect of pressure [ENDORSED]

If one starts with a higher pressure of reactant, the equilibrium constant will be larger.
Why is this false?
by manasa933
Wed Nov 29, 2017 8:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 1
Views: 91

Bond angle

According the solutions manual, the bond angle of ClO2+ is slightly less than 120 degrees and its electron arrangement is trigonal planar.

But since there are two lone pairs on the chlorine atom, shouldn't it be tetrahedral and slightly less than 90 degrees?
by manasa933
Tue Nov 28, 2017 10:09 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Heteronuclear diatomic species
Replies: 1
Views: 141

Heteronuclear diatomic species

How do you draw the molecular orbital energy level diagram for 2 atoms that combine from different periods (as their valence electrons belong to different shells)?
by manasa933
Tue Nov 28, 2017 10:06 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Energy levels
Replies: 2
Views: 203

Energy levels

Why is the order of energy levels different in n2 from o2 and f2?
by manasa933
Tue Nov 28, 2017 4:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: SF6
Replies: 1
Views: 94

SF6

The bond angles of sf6 are said to be 90 and 180 from the textbook, but since it's octahedral, wouldn't it only be 90?
by manasa933
Fri Nov 24, 2017 10:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: IF7
Replies: 2
Views: 139

Re: IF7

It is pentagonal bipyramidal.
by manasa933
Fri Nov 24, 2017 10:14 pm
Forum: Naming
Topic: Cyano vs Cyanido
Replies: 3
Views: 161

Re: Cyano vs Cyanido

Both are acceptable. Cyano is just an older term.
by manasa933
Thu Nov 23, 2017 10:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Expanded octet
Replies: 6
Views: 201

Expanded octet

How would you know whether an atom has an expanded octet?
by manasa933
Sun Nov 19, 2017 11:56 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 146

Re: Polydentate

If a ligand has more than one donor atom (an atom that can bond with the central metal atom) it is polydentate.
by manasa933
Sun Nov 19, 2017 11:54 am
Forum: Lewis Structures
Topic: Best way to start Lewis Structures
Replies: 12
Views: 423

Re: Best way to start Lewis Structures

I would say draw electrons and then bonds!
by manasa933
Mon Nov 06, 2017 10:02 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H- atom equation for other elements
Replies: 1
Views: 109

Re: H- atom equation for other elements

multiply the energy by atomic number (Z) squared!
by manasa933
Mon Nov 06, 2017 10:40 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy of subshells
Replies: 2
Views: 153

Energy of subshells

Does 4d or 5s have a greater energy and why?
by manasa933
Thu Nov 02, 2017 9:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence electrons
Replies: 3
Views: 187

Valence electrons

Why is the number of valence electrons for silver 11 and not 1 as 5 is the outermost shell?

N: 1s2,2s2,2p6,3s2,3p6,3d10,4s2,4p6,4d10,5s1
by manasa933
Thu Nov 02, 2017 6:19 pm
Forum: Quantum Numbers and The H-Atom
Topic: Core, Closed shell, and valence electrons
Replies: 2
Views: 170

Core, Closed shell, and valence electrons

Are valence electrons the electrons in the outermost orbital or shell?
Is the inner core basically all the closed shells?
by manasa933
Thu Nov 02, 2017 4:38 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Quantum Numbers
Replies: 3
Views: 131

Re: Quantum Numbers

l can go to a higher level but we're not dealing with them in this class.
by manasa933
Thu Nov 02, 2017 4:13 pm
Forum: Trends in The Periodic Table
Topic: Diagonal relationships
Replies: 1
Views: 100

Diagonal relationships

What gives rise to diagonal relationships?
by manasa933
Tue Oct 24, 2017 12:38 pm
Forum: *Shrodinger Equation
Topic:
Replies: 4
Views: 321

Re:Hψ

Hψ represents hamiltonian and is equal to the sum of the potential and kinetic energy.
by manasa933
Mon Oct 23, 2017 11:06 pm
Forum: Trends in The Periodic Table
Topic: Trends of ionic radius
Replies: 4
Views: 225

Trends of ionic radius

Why is the following true:
Cations are smaller than their parent atoms, whereas anions are larger.
by manasa933
Thu Oct 19, 2017 5:34 pm
Forum: Photoelectric Effect
Topic: Textbook 1.38
Replies: 1
Views: 140

Textbook 1.38

What is the wavelength of an electron when the distance it travels in 1 s is equal to its wavelength?
by manasa933
Tue Oct 17, 2017 7:47 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect as Proof of Particle Qualities of Light
Replies: 3
Views: 201

Re: Photoelectric Effect as Proof of Particle Qualities of Light

A photon is causing the ejection of an electron which is a particle and hence, proving the particle nature of light.
by manasa933
Tue Oct 17, 2017 7:46 pm
Forum: Properties of Electrons
Topic: Rydberg's formula
Replies: 6
Views: 475

Re: Reinberg's formula

Different levels signify the different energies the electrons will possess when in that level. Rydberg's equation correlates energy levels with the frequency of the electron in that level. It depends on the question. Sometimes, they may want you to find out the initial or final energy level using th...
by manasa933
Tue Oct 17, 2017 7:44 pm
Forum: DeBroglie Equation
Topic: 1.39 Help
Replies: 5
Views: 283

Re: 1.39 Help

Hey,

So first convert the mass into kgs and the mph to m/s so they're in SI units.

Then use De Broglie's equation:
L=h/p or L=h/mv
We know the mass and velocity.
h ---> Planck's constant
by manasa933
Sat Oct 14, 2017 7:28 pm
Forum: Properties of Light
Topic: Excitation of electrons
Replies: 5
Views: 216

Excitation of electrons

If 1 million photons in the UV region are absorbed by a hydrogen gas sample how many electrons are excited to a higher energy level?

a.zero
b.500,00
c.1
d.1 million
by manasa933
Sat Oct 14, 2017 2:19 pm
Forum: Properties of Light
Topic: 1.3 homework [ENDORSED]
Replies: 11
Views: 441

Re: 1.3 homework [ENDORSED]

A) no, speed of radiation, c, is always 3 x 10(to the power 8) B) no, Frequency is inversely proportional to wavelength, and so, if the frequency decreases, wavelength should increase C) yes, as the wave gets wider when frequency decreases, the wave is less susceptible to change in electric field. D...
by manasa933
Thu Oct 12, 2017 11:17 am
Forum: Properties of Electrons
Topic: Electrons and photons [ENDORSED]
Replies: 1
Views: 222

Electrons and photons [ENDORSED]

Suppose the energies of levels are as follows: n=1, E=-13.6 eV n=2, E=-3.4 eV n=3, E=-1.51 eV A photon of energy 11 eV, which is slightly greater than the difference between the energies of level 1 an 2, will the electron jump to the 2nd level from the first or will it remain in the 1st level as the...
by manasa933
Mon Oct 09, 2017 12:37 pm
Forum: Student Social/Study Group
Topic: Online lectures
Replies: 1
Views: 280

Online lectures

Hey

Does anyone know where we can view the lectures and our grades?
by manasa933
Sun Oct 08, 2017 4:31 pm
Forum: Photoelectric Effect
Topic: Post-assessment problem
Replies: 3
Views: 180

Post-assessment problem

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. a. What is the KE? b. How much is the energy required to remove an electron from one sodium atom? c. What is the frequency of the incident light? Don't we n...
by manasa933
Sun Oct 08, 2017 12:24 pm
Forum: Photoelectric Effect
Topic: Units for photoelectric effect
Replies: 2
Views: 179

Re: Units for photoelectric effect

Plancks constant unit : J s
Frequency: Hertz (Hz)
KE: Joules (J)
Work function: Joules (J)
by manasa933
Sun Oct 08, 2017 12:19 pm
Forum: Molarity, Solutions, Dilutions
Topic: G25
Replies: 1
Views: 169

G25

Practitioners of the branch of alternative medicine known as homeopathy claim that very dilute solutions of substances can have an affect. Is this claim plausible? To explore this question, suppose that you prepare a solution of an active substance X, with a molarity of 0.10 mol per liter. Then you ...
by manasa933
Mon Oct 02, 2017 7:49 pm
Forum: Molarity, Solutions, Dilutions
Topic: G5 from fundamentals!
Replies: 3
Views: 236

G5 from fundamentals!

So I used the formula m(initial) x v(initial) = m(final) x v(final) and substituted the following:

m(initial) = 0.079 M
v(initial) = 250 ml
m(final) = 2.15 x 10 (to the power -3)

But in the solutions manual they didn't have the v(initial) anywhere.

Please help!!

Go to advanced search