Search found 13 matches

by Arlene Paramo 1I
Thu Jan 14, 2016 9:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 2
Views: 699

Bond Enthalpy

When to do you make the standard reaction enthalpy negative? Is it when you're breaking or forming a bond and why does it need to be negative?
by Arlene Paramo 1I
Sun Jan 10, 2016 12:19 pm
Forum: Phase Changes & Related Calculations
Topic: Isolated systems
Replies: 1
Views: 316

Isolated systems

If a system is isolated is there no transfer of energy or does it occur within the system itself?
by Arlene Paramo 1I
Thu Dec 03, 2015 2:23 pm
Forum: General Science Questions
Topic: Identifying M2+ cations
Replies: 1
Views: 900

Identifying M2+ cations

An electron configuration is given [Ar] 3d4 and they ask to identify the M2+ cation. I don't understand why the answer is Cr2+ is this a characteristic of transition metals?
by Arlene Paramo 1I
Mon Nov 23, 2015 9:18 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question regarding units
Replies: 1
Views: 367

Re: Question regarding units

Bar and atm are gas constant therefore you can use either one. You just have to stay consistent with your units.
by Arlene Paramo 1I
Sat Nov 21, 2015 12:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Units for Partial Pressure When Given Kp
Replies: 2
Views: 635

Re: Units for Partial Pressure When Given Kp

It depends on which gas constant you decide to choose(atm or bar) either unit is correct. Unless it specifies which one to use you can just decide which unit to use.
by Arlene Paramo 1I
Mon Nov 16, 2015 3:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: relationship between Kp and Kc
Replies: 2
Views: 657

Re: relationship between Kp and Kc

You derive it from the ideal gas equation PV=nRT. By using the ideal gas law you should be able to get Kc from the initial Kp.
by Arlene Paramo 1I
Tue Nov 10, 2015 6:28 pm
Forum: Naming
Topic: HW 17.31 part d
Replies: 2
Views: 436

Re: HW 17.31 part d

(OH2)2 and (H2O)2 are the same thing, two hydrogen and one oxygen therefore it doesn't matter which one you chose they are both the same thing.
by Arlene Paramo 1I
Wed Nov 04, 2015 10:14 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: molecular orbital theory
Replies: 2
Views: 443

molecular orbital theory

when do we start from instead of ?
by Arlene Paramo 1I
Tue Oct 27, 2015 5:22 pm
Forum: Ionic & Covalent Bonds
Topic: Oxidation state
Replies: 1
Views: 401

Oxidation state

How do you determine the maximum positive and negative oxidation number that an element can have?
by Arlene Paramo 1I
Wed Oct 21, 2015 9:24 pm
Forum: Lewis Structures
Topic: Exceptions to the Octet Rule
Replies: 3
Views: 354

Re: Exceptions to the Octet Rule

It's H, He, Li, and Be because they are stable with two valance electrons and the noble gases because they already have all eight valence electrons.
by Arlene Paramo 1I
Tue Oct 13, 2015 1:56 pm
Forum: Molarity, Solutions, Dilutions
Topic: Quiz 1 preparation 3, #4
Replies: 1
Views: 512

Re: Quiz 1 preparation 3, #4

You have to use the equation M1 x V1=M2 x V2. Just plug in the numbers and rearrange the equation you should find the volume.
M1= 0.642 M KOH
M2=.101 M KOH
V1=1.00 L
by Arlene Paramo 1I
Thu Oct 08, 2015 6:28 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quiz 1 Question 10
Replies: 2
Views: 435

Re: Quiz 1 Question 10

They want you first to use E=hv and get the Energy. Once you get the energy you have to use Rydberg to solve for the principal quantum number. So the E that you got in the E=hv will be used in En=R(1/n^2 -1/n^2). From there you plug in n=4 and all the constants and you should get the answer.
by Arlene Paramo 1I
Wed Sep 30, 2015 5:28 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1.15 How do you go from 102.6 nm to 102.6 x 10^-9m?
Replies: 2
Views: 379

1.15 How do you go from 102.6 nm to 102.6 x 10^-9m?

How do we know the exponent of the given information? If we are given 102.6 nm how do we get 102.6 x 10^-9 m? Does it have to do with the hydrogen or where does it come from? Other questions also went from 10^-7m to nm. What is the relation?

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