Search found 20 matches

by Jasmine Lam 1I
Mon Mar 07, 2016 8:22 pm
Forum: *Haloalkenes
Topic: Ester and Amide
Replies: 1
Views: 656

Ester and Amide

For the Homework question 2.46 in the Intro to OChem book, the picture includes functional groups like ester and amide, do we need to know them for the final or no? I know amide is basically (-NH-) but for ester, it is quite confusing...

Thanks for helping guys :)
by Jasmine Lam 1I
Mon Feb 29, 2016 9:50 pm
Forum: *Cycloalkanes
Topic: Numbering hydrocarbons
Replies: 2
Views: 394

Numbering hydrocarbons

Can someone please explain how do we number hydrocarbons? Like Dr.Lavelle said something like "use the lowest number but not the "'sum"'? What does he mean by that? For example 1.17 in the chapter work, why do we call the molecule 4-tert-butyl-1,2-dimethylcyclohexane instead of 1-tert...
by Jasmine Lam 1I
Thu Feb 25, 2016 12:46 am
Forum: *Alkanes
Topic: IUPAC vs non IUPAC naming
Replies: 2
Views: 314

Re: IUPAC vs non IUPAC naming

The IUPAC naming is honestly sufficient for naming and stuff, but they might test u to write out the equation or structure of a molecule with a non IUPAC name.
Eg. What is isopropyl-butane?

Thats rly the case you need to know it for.

Hope that helps:)
by Jasmine Lam 1I
Wed Feb 17, 2016 12:20 pm
Forum: First Order Reactions
Topic: Lecture 2/8
Replies: 1
Views: 362

Re: Lecture 2/8

The slow step is the steps that determines the rate law. For example:
2nd order rxn:
Rxn1. A+B-->C (bimolecular) (slow)
Rxn2. B+D-->F (bimolecular) (fast)
the rate law for the rxn will then be k[A][B] --> second order because of bimolecular structure.

Hope that helps :)
by Jasmine Lam 1I
Fri Feb 12, 2016 9:43 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Salt Bridge
Replies: 5
Views: 889

Re: Salt Bridge

The salt bridge is necessary in redox reaction as it is used to remain charge balance between the anode cell and the cathode cell, preventing the rxn to go to equilibrium rapidly. However, there are also couple substitute for a salt bridge like: membrane paper that allows electrons flow, as the elec...
by Jasmine Lam 1I
Sun Feb 07, 2016 1:32 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Winter 2012 Midterm Question 7B
Replies: 1
Views: 386

Re: Winter 2012 Midterm Question 7B

Hi, I did the same thing as you and I think that was a typo as the calculations that come after "n=1" did n=2 instead.

Hope that helps. :)
by Jasmine Lam 1I
Wed Feb 03, 2016 3:07 pm
Forum: Balancing Redox Reactions
Topic: Basic Half Reactions
Replies: 1
Views: 315

Basic Half Reactions

Can someone explain how do we balance basic half reactions?
Especially when it's a reaction like:
C(s)--> CH3(aq)
HW14.5
by Jasmine Lam 1I
Mon Jan 25, 2016 10:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: ∆U in Isothermal Reversible Expansion
Replies: 2
Views: 408

Re: ∆U in Isothermal Reversible Expansion

Internal energy is due to motion of particles in a system. As internal energy depends on temperature. As we know temperature in isothermal process is constant so the internal energy will also be constant thus the change in internal energy will be zero.

I hope this is right :/
by Jasmine Lam 1I
Wed Jan 20, 2016 10:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy Units
Replies: 1
Views: 519

Standard Enthalpy Units

For homework question 8.63,

Whenever we calculate the standard reaction enthalpy (∆Ho) using standard enthalpy of formation (∆Hfo), why is the unit kJ instead of kJ/mol (when the standard enthalpies of formation are given in kJ/mol)?

Thanks for helping! :)
by Jasmine Lam 1I
Fri Jan 15, 2016 4:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State function
Replies: 2
Views: 358

Re: State function

Heat is not a state function because it depends on the pressure during heating/cooling and not just the initial and final temperatures and pressure, while enthalpy is measured at constant pressure. State functions are step independent functions and only the initial and the final values matter, not t...
by Jasmine Lam 1I
Fri Jan 08, 2016 11:28 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: heat and state function
Replies: 2
Views: 389

heat and state function

Why is heat not a state function but enthalpy is?
What are state functions?
Thanks :)
by Jasmine Lam 1I
Fri Dec 04, 2015 10:38 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Numbers and Shape
Replies: 3
Views: 1051

Re: Coordination Numbers and Shape

You can actually tell the shape of a coordination complex simply by its formula :) First, count the bonds it make: [Co(NH3)5Cl] - Co forms bonds with 5 NH3 and one Cl --- 6 bonds, making it a octahedral [Fe(CN)6] - Fe forms bonds with 6 CN-, 6 bonds, making it a octahedral However, for ethylenediami...
by Jasmine Lam 1I
Thu Nov 19, 2015 1:32 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature and Equilibrium
Replies: 1
Views: 349

Re: Temperature and Equilibrium

1. Usually when a reaction requires breaking bonds like: B2 <--> 2B it is endothermic as energy is usually required to break bonds. 2. Moreover, some questions give you the ΔH of the reaction: - ΔH positive: reaction is endothermic as heat is absorbed to make the reaction happen. - ΔH negative: reac...
by Jasmine Lam 1I
Fri Nov 13, 2015 10:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Setting X as 0 when calculating equilibrium conc.
Replies: 1
Views: 244

Setting X as 0 when calculating equilibrium conc.

When and why do we set X as 0 when we calculate the equilibrium constant? I understand that it will simplify the calculation as it helps us avoid solving cubic equations but I just don't know when the value will be small enough to 0.
by Jasmine Lam 1I
Fri Nov 06, 2015 10:21 am
Forum: Dipole Moments
Topic: Polarity of XeF2
Replies: 4
Views: 12633

Re: Polarity of XeF2

For Xe, it has 8 valence electrons and it forms 2 bonds in total with the 2 Fs. However, XeF2 has 22 valence electrons; therefore, after giving each F 1 bond and 6 valence electrons to fulfill the octet rule, Xe should still have 3 lone pair. 2 pairs go above Xe and one pair go below it. These valen...
by Jasmine Lam 1I
Fri Oct 30, 2015 10:29 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Changes on Bond Order
Replies: 1
Views: 224

Changes on Bond Order

Consider a hypothetical species He-H.
What charge, if any, should be present to produce the most stable molecule or ion possible?
If the charge on the most stable species were increased or decreased by one, what would be the effect on the bond order?
by Jasmine Lam 1I
Fri Oct 23, 2015 10:26 am
Forum: Lewis Structures
Topic: Ch.4 23a), b)
Replies: 1
Views: 310

Ch.4 23a), b)

23.a) OSbCl3
b) SO2Cl2

To draw the lewis dot structure for both of these, should we use double bonds to make it more stable?
The solution manual only uses single bonds but wouldn't making a double bond for oxygen stabilize the molecules more?

Thanks :)
by Jasmine Lam 1I
Fri Oct 16, 2015 10:12 am
Forum: Trends in The Periodic Table
Topic: group 15 electron affinity
Replies: 1
Views: 814

group 15 electron affinity

Why is group 15 an 18's electron affinity significantly low?
by Jasmine Lam 1I
Fri Oct 09, 2015 10:49 am
Forum: Photoelectric Effect
Topic: Photoelectric Effect Question
Replies: 1
Views: 371

Photoelectric Effect Question

Question: If long wavelength light is not ejecting electrons from a metallic surface, will increasing the intensity of the light eject an electron? And why? A. No, because the experimental light is not acting like a wave B. No, because decreasing intensity increases the number of electrons ejected C...
by Jasmine Lam 1I
Fri Oct 02, 2015 10:22 am
Forum: Empirical & Molecular Formulas
Topic: L35
Replies: 4
Views: 2204

L35

Sodium bromide, NaBr, which is used to produce AgBr for use in photographic film, can itself be prepared as follows.
FeBr+Br2 ---> FeBr2
FeBr2+Br2---> Fe3Br8
Fe3Br8+Na2CO3-->NaBr+CO2+FE3O4
What mass of iron, in kg, is needed to produce 2.50t of NaBr?

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