## Search found 95 matches

Sun Mar 08, 2020 5:58 pm
Forum: Zero Order Reactions
Topic: Concept Behind 0 Order Reactions
Replies: 1
Views: 25

### Re: Concept Behind 0 Order Reactions

I remember him saying that they're colliding against other molecules in the solution.
Sun Mar 08, 2020 5:53 pm
Forum: First Order Reactions
Topic: Half Life
Replies: 8
Views: 93

### Re: Half Life

If you look at how half life is derived from the original 1st order reaction equation the initial concentration is canceled out when deriving the half life, which is why it doesn't matter.
Sun Mar 08, 2020 5:48 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Units
Replies: 2
Views: 51

### Re: Units

If you look at each equation and plug in the units for each variable, solving for K will give you different units for zero, first, and second order.
The units are different because the equations are different.

For zero order, K = m/L x S
For first order, K = 1/sec
For second order, K= L/ mol x sec
Sun Mar 08, 2020 5:41 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: thermodynamically stable
Replies: 6
Views: 113

### Re: thermodynamically stable

For something to be thermodynamically stable, it has to be spontaneous right? Even though it will not react
Sun Mar 08, 2020 5:37 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow step
Replies: 2
Views: 41

### Slow step

Given a rate law and some proposed mechanisms, How do you determine which one is the slow step?

Is it the one that matches the given rate law, but what if none of them do?
Sun Mar 01, 2020 2:43 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: delta G = -nFE
Replies: 6
Views: 82

### Re: delta G = -nFE

Consider the cell Ag(s)uAg1(aq, 5.0 mmol?L21)uuAg1(aq, 0.15 mol?L21)uAg(s). Can this cell do work? If so, what is the maximum work that it can perform (per mole of Ag)?

Hello using this equation for 6N17 gives you max work as a positive value. Based off the equation shouldn't it be negative?
Sun Mar 01, 2020 2:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.13
Replies: 2
Views: 42

### Re: 6M.13

Even though your reaction may be flipped, you use the E naught value given because E naught is your reaction potential. It's not like Delta H naught where you can use Hesse's Law to change the signs or multiply. If you manipulate the equation the E naught stays the same.
Sun Mar 01, 2020 2:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 10
Views: 71

### Re: Salt Bridge

I noticed that some cell diagrams in the homework don't include salt bridges.. when is this possible?
Sun Mar 01, 2020 2:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 10
Views: 71

### Re: Salt Bridge

I noticed that some cell diagrams in the homework don't include salt bridges.. when is this possible?
Sun Mar 01, 2020 2:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 6N15.
Replies: 2
Views: 63

### 6N15.

6N15. Calculate the potential of a cell constructed with two nickel electrodes. The electrolyte in one compartment is 1.0 m Ni(NO3)2(aq). In the other compartment, NaOH has been added to a Ni(NO3)2 solution until the pH 5 11.0 at 298 K. See Table 6I.1. I calculated this by assuming it's a concentrat...
Sun Mar 01, 2020 2:13 pm
Forum: Balancing Redox Reactions
Topic: 6N.1
Replies: 2
Views: 54

### Re: 6N.1

It's a mistake and you get the right answer if you use one.
Sun Mar 01, 2020 10:06 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6.N3 (a)
Replies: 4
Views: 56

### 6.N3 (a)

We're asked to predict the cell potential for 6N3. I'm having trouble with (a) Pt(s)|H2(g, 1.0 bar)|HCl(aq, 0.075 mol?L21) ||HCl(aq, 1.0 mol?L21)| H2(g, 1.0 bar)|Pt(s) I know you use the equation E=-RT/nF(logQ) because it is a concentration cell. I'm having trouble figuring out why n=1 how do you ca...
Sun Feb 23, 2020 11:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Balancing Equations
Replies: 5
Views: 57

### Re: Balancing Equations

If the oxidation number is increasing, it's being oxidized.
If the oxidation number is decreasing, it's being reduced.
Sun Feb 23, 2020 11:12 pm
Forum: Balancing Redox Reactions
Topic: Reduced/Oxidized
Replies: 5
Views: 52

### Re: Reduced/Oxidized

^^^
also, if you start balancing it with H+/OH- and H2O, a charge will pop up and you can tell based off that.
Sun Feb 23, 2020 11:07 pm
Forum: Balancing Redox Reactions
Topic: 6K.3D balancing problem?
Replies: 4
Views: 57

### Re: 6K.3D balancing problem?

I believe you write Cl2 --> 2Cl- in the products because this is the only way to go about doing the reduction. If you leave it as Cl2 --> Cl2 nothing is really happening in the reaction and rewriting it is equivalent but now you have a charge to work with.
Sun Feb 23, 2020 11:02 pm
Forum: Balancing Redox Reactions
Topic: Acids and Bases
Replies: 4
Views: 101

### Re: Acids and Bases

In acidic solutions you add H+ and in basic you add OH-

you basically add H20 in order to balance out the O
and H+/OH- to balance out the H

It can get more complicated so I recommend reading Toolbox 6k.1 and looking at examples in the book.
Sun Feb 23, 2020 10:59 pm
Forum: Van't Hoff Equation
Topic: deltaS/R
Replies: 7
Views: 107

### Re: deltaS/R

In the equation you use to compare two temperatures you don't ignore deltaS/R it's just canceled out when subtracting the equations lnK(2)-lnk(1), lnk= (-delta H naught/RT) - (delta S naught/R).
Sun Feb 16, 2020 1:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Work and Gibbs Free Energy
Replies: 3
Views: 34

### Re: Work and Gibbs Free Energy

Delta G equals the maximum amount of work done at constant pressure and temperature.

I'm not sure if this is what you were asking but I hope it helps.
Sun Feb 16, 2020 1:04 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Van't Hoff Equation
Replies: 2
Views: 28

### Re: Van't Hoff Equation

Delta G equals zero when a reaction is at equilibrium, or when Q=K or K=1.

Van Hoff's equation is derived from delta G= delta H-Tdelta S. It is not used when G = zero, it is used to calculate K at different temperatures.
Sun Feb 16, 2020 1:00 pm
Forum: Balancing Redox Reactions
Topic: class example
Replies: 2
Views: 41

### Re: class example

That's correct. You know Mn has to be +7 in MnO4- because O4 has an overall -8 charge and the molecule has a -1 charge.

It is then being reduced to Mn 2+, as it's oxidation number decreases.
Sun Feb 16, 2020 12:57 pm
Forum: Balancing Redox Reactions
Topic: Number of electrons
Replies: 5
Views: 60

### Number of electrons

When writing redox reaction equations,
If it is an oxidation reaction do you always write the number of electrons in the products? and for a reduction in the reactants?
Sun Feb 16, 2020 12:56 pm
Forum: Balancing Redox Reactions
Topic: half reaction
Replies: 8
Views: 82

### Re: half reaction

When writing half reactons why is the number of electrons written in the equation being added?

For example in this oxidation:
5Fe = Fe3+ + 5e-

Why is the 5e- added and not subtracted?
Sun Feb 09, 2020 9:20 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy of transition
Replies: 8
Views: 94

### Re: Entropy of transition

How can you identify when you need to break the reaction down into 3 steps of heating, vaporization, then cooling?
Sun Feb 09, 2020 9:18 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: boltzmann equation
Replies: 4
Views: 50

### Re: boltzmann equation

Degeneracy, W: X^n

X: #of possible states
n: #number of particles
Sun Feb 09, 2020 9:08 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Law of Conservation Energy
Replies: 5
Views: 40

### Re: Law of Conservation Energy

Yes, deltaU= q+W = 0 for an insolated system in an isolated universe demonstrates this.
Energy is neither created or destroyed, q= -w
Sun Feb 09, 2020 9:04 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Difference between Cv and Cp?
Replies: 8
Views: 90

### Re: Difference between Cv and Cp?

Cv is heat capacity at constant volume and Cp is heat capacity at constant pressure.
For atoms that are ideal gases:
Cv: 3/2 R
Cp: 5/2 R
Sun Feb 09, 2020 8:37 pm
Forum: Ideal Gases
Topic: reversing reactions
Replies: 14
Views: 197

### Re: reversing reactions

In a forward reaction, you do products over reactants for the equilibrium equation. For the reverse it is technically reactants over products, so it makes sense that your K would be 1/K for the reverse.
Sun Feb 02, 2020 7:44 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law vs Bond Enthalpies vs Standard Enthalpies of Formation
Replies: 7
Views: 53

### Re: Hess's Law vs Bond Enthalpies vs Standard Enthalpies of Formation

I'm a bit confused about standard enthalpy of formation. So the definition is enthalpy for the formation of one mole of a substance from its elements in their most stable form and the standard enthalpy of formation of an element in its most stable form is zero. If it is always zero, why are we asked...
Sun Feb 02, 2020 7:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Method 2
Replies: 2
Views: 62

### Method 2

Can you use bond enthalpy of the products minus reactants in Method 2?
Or does that only work in Method 3 with Standard Enthalpy of Formation?
Sun Feb 02, 2020 7:33 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Constant pressure
Replies: 2
Views: 38

### Constant pressure

What conditions indicate that a reaction is at constant pressure?
How would you know if it involves changes in the number of moles of gas (P delta V is sigfnificant)??
Sun Feb 02, 2020 7:28 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: Types of entropy
Replies: 2
Views: 26

### Types of entropy

What is positional entropy and what equation should I use to calculate it?
Sun Feb 02, 2020 7:22 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: boltzmann equation
Replies: 4
Views: 50

### Re: boltzmann equation

Building on this,
Can someone further explain the Boltzmann equation?

If we were calculating 5 particles in one of two states would W be 2^5 ??
Sun Feb 02, 2020 7:16 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 421

### Re: Midterm

Does anyone know if all the thermochemistry and thermodynamic equations will be supplied on the midterm?
Sun Jan 26, 2020 1:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: adding enthalpy of phase changes
Replies: 2
Views: 22

### adding enthalpy of phase changes

For the notes on method 2, Lavelle said to remember that you need to add enthalpy of phase changes for liquids and solids.
Can someone explain this futher? Would you add it to the final HRXN?
Sun Jan 26, 2020 1:47 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: using volume in calculations
Replies: 2
Views: 52

### Re: using volume in calculations

Yes, I believe you would assume it is a cylinder shape.
Sun Jan 26, 2020 1:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: value for r
Replies: 2
Views: 25

### Re: value for r

Use the R that will cancel your units so you are left with J.
When doing the equation make sure to write out the units so you can see if they cancel.

It also helps to remember that J is the same as 1kg.m^2.s^-2
Sun Jan 26, 2020 1:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Method One (Hess’s Law)
Replies: 4
Views: 55

### Re: Method One (Hess’s Law)

If you have two equations that can be added together to get the wanted composite equation, you can add the deltaHRXN of each equation to get the net deltahHRXN.
Sun Jan 26, 2020 1:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Method Three
Replies: 1
Views: 19

### Re: Method Three

You used method three to calculate the standard enthalpy of formation if bond enthalpies are not available. The equation is (standard enthalpy of formation of the products) - (standard enthalpy formation of the product) = overall standard reaction enthalpy Make sure the reaction is balanced and mult...
Sun Jan 19, 2020 2:17 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw question
Replies: 2
Views: 21

### Kw question

Is [h30+][0h-]= 1.0 x 10^-14 always true? what conditions does the reaction need to be under for this to be true ?
Sun Jan 19, 2020 2:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D. 19
Replies: 1
Views: 17

### 6D. 19

A sample of CH3NH3Cl of mass 15.5 g is dissolved in water to make 450. mL of solution. What is the pH of the solution? I keep doing this and getting a PH of 2.6, the answers say it's supposed to be 5.42. I found the Ka to be 2.3 X 10^-5 = x^2/0.265-x I get x to be .0025 can someone tell me what i'm ...
Sun Jan 19, 2020 2:12 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B.9
Replies: 3
Views: 30

### Re: 6B.9

I also got a negative number.

Can ph be negative?
Sun Jan 19, 2020 2:09 am
Forum: Ideal Gases
Topic: inert gas
Replies: 5
Views: 37

### Re: inert gas

Inert gases are noble gases that don't undergo chemical reactions. Noble gases often don't react with other substances because they're stable.
Sun Jan 19, 2020 12:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.5
Replies: 2
Views: 57

### 6D.5

Calculate the pH, pOH, and percentage protonation of sol- ute in each of the following aqueous solutions: (a) 0.057 m NH3(aq); (b) 0.162 m NH2OH(aq); (c) 0.35 m (CH3)3N(aq); (d) 0.0073 m codeine, given that the pKa of its conjugate acid is 8.21. Can someone please give a step by step for part (a)? I...
Thu Jan 09, 2020 11:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.3
Replies: 4
Views: 62

### Re: 5H.3

When you manipulate an equation you also manipulate the K value, which is why you multiply the K values of the two equations to get your composite equation's K value.

For example if you multiply an equation by 2 you square the K value.
Thu Jan 09, 2020 11:29 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Re: Q and Ke: Small K value and Large K value
Replies: 7
Views: 60

### Re: Q and Ke: Small K value and Large K value

If Q is less than K this tells you that products still need to form, so the reaction will go forward.
If Q is greater than K it tells you that there are more products and the reaction must go back towards the reactants.
Thu Jan 09, 2020 11:26 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K values
Replies: 4
Views: 52

### K values

I know that when K is less than 10^-3 it favors the reacts,

but how strict is this cut off? if K is a little more than 10^-3 is it close enough to 10^-3 that it still favors the reactants? or does it favor neither products or reactants?
Thu Jan 09, 2020 11:19 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K of Ionic Compounds in Solution
Replies: 4
Views: 43

### Re: K of Ionic Compounds in Solution

A net ionic equation should only include what participates in forming the product, which is why you leave out spectator ions (ions that merely "spectate" without contributing). Spectator ions appear on opposite sides of a chemical equation and therefore cancel out.
Thu Jan 09, 2020 11:11 am
Forum: Ideal Gases
Topic: 5G.9 -- Partial Pressures?
Replies: 2
Views: 45

### Re: 5G.9 -- Partial Pressures?

The partial pressure of 02 is different because the second experiment contains 0.5 mol 03 while the first one contains 0.1mol 03. Although the amount of Liters is the same, the different initial molar amounts of 03 change the overall partial pressure. This will affect the partial pressure of 02.
Sun Dec 01, 2019 11:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs Non-polar
Replies: 4
Views: 89

### Re: Polar vs Non-polar

If you look at a tetrahedral shape as an example, It is nonpolar if all the 4 surrounding molecules are the same element because the dipoles cancel out. The structure is symmetrical. but, If you have a tetrahedral shape in which the surrounding molecules are different elements, it will be polar. The...
Sun Dec 01, 2019 10:59 pm
Forum: Resonance Structures
Topic: Carbon
Replies: 4
Views: 160

### Re: Carbon

Carbon cannot exceed the octet rule. It is not large enough, not past the third row, and based on its valence number it likes to form 4 bonds.
Sun Dec 01, 2019 10:57 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Relation with Transition Metals
Replies: 1
Views: 23

### Re: Relation with Transition Metals

a coordination compound consists of a transition metal and ligands that are attached to it.
Sun Dec 01, 2019 10:18 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 12
Views: 161

### Re: Cisplatin

is cisplatin a chelate?
Sun Nov 24, 2019 4:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand
Replies: 4
Views: 54

### Re: Ligand

Ligands are neutral molecules/anions that bond to a central atom, forming a coordination complex.
Sun Nov 24, 2019 4:05 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition metals
Replies: 4
Views: 107

### Transition metals

Do transition metal cations always form complexes w H20?
Sun Nov 24, 2019 3:54 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 3
Views: 36

### Re: Coordination Number

The coordination number is just the number of bonds attached to the central atom and within the coordination sphere.
Sun Nov 24, 2019 3:51 pm
Forum: Biological Examples
Topic: Porphyrin ligand
Replies: 1
Views: 44

### Porphyrin ligand

Can someone explain the "cage" around the porphyrin ligand? and how it relates to its function?

Thank you!
Sun Nov 24, 2019 3:48 pm
Forum: Naming
Topic: Order
Replies: 4
Views: 75

### Order

When naming a coordination compound
I know you name the ligand first but then is it the anion or transition metal?
Sun Nov 24, 2019 3:37 pm
Forum: Lewis Acids & Bases
Topic: lewis vs. bronsted
Replies: 10
Views: 136

### Re: lewis vs. bronsted

A Bronsted Acid is a proton donor, a Lewis Acid accepts an electron pair. These are interchangeable because they are saying the same thing. When a proton is donated, the molecule becomes more negative, which is like accepting an electron pair. Bronsted and Lewis acids are the same thing, just a diff...
Sat Nov 16, 2019 10:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 4
Views: 49

### Re: VSEPR

I don't think you can ever have two central atoms.
When there appears to be two you regard them as different shapes. For example, you can have a compound with two trigonal planar shapes.
Sat Nov 16, 2019 6:06 pm
Forum: Electronegativity
Topic: ionic character
Replies: 9
Views: 262

### Re: ionic character

Why does CF4 have greater ionic character than CH4?
Sat Nov 16, 2019 6:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 343

### Re: Bent or Angular

So, the bond angle in H 2 O is 104.5 degrees (from the textbook). On test 2, should we state that the bond angle for all angular molecules is 104.5 degrees or should we just say less than 120 degrees? To answer the question above, You would say it is less than 109.5 degrees 109.5 degrees is the pre...
Sat Nov 16, 2019 5:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 6
Views: 98

### Re: Shape

I don't think it matters too much, but I'd go with bent to be safe, but the names are interchangeable.
Sat Nov 16, 2019 5:52 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 7
Views: 102

### Re: Polarity

The dipole moments do cancel out, the shape is symmetrical, and the surrounding atoms are the same. Their dipoles point in the same direction, so they should cancel out making CCl4 nonpolar.
Sat Nov 09, 2019 9:04 pm
Forum: Dipole Moments
Topic: Electronegativity on Dipoles
Replies: 3
Views: 33

### Re: Electronegativity on Dipoles

Will a difference in electricity always mean that there is a dipole moment?
Sat Nov 09, 2019 9:02 pm
Forum: Bond Lengths & Energies
Topic: Bond Dissociation Energies vs. Bond enthalpy
Replies: 2
Views: 35

### Re: Bond Dissociation Energies vs. Bond enthalpy

Yes!

The stronger the bond the higher the dissociation energy.
Sat Nov 09, 2019 9:00 pm
Forum: Dipole Moments
Topic: Dipole-dipole, LDF, HB
Replies: 1
Views: 43

### Dipole-dipole, LDF, HB

What are the main differences between Dipole- Dipole, London Dispersion forces, and Hydrogen Bonding?

How are these ranked in terms on energy?
Sat Nov 09, 2019 8:54 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polar and Ionic Bond Character
Replies: 3
Views: 54

### Re: Polar and Ionic Bond Character

What is covalent character in an ionic bond?
Sat Nov 09, 2019 8:50 pm
Forum: Ionic & Covalent Bonds
Topic: Polarizability
Replies: 4
Views: 76

### Polarizability

Why are large anions highly polarizable?
Sun Nov 03, 2019 8:32 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 10
Views: 113

### Re: Nodal Planes

P and D orbitals have a nodal plane, zero electron density (non-symmetric)
S orbitals have no nodal planes (symmetric electron distribution)
Sun Nov 03, 2019 8:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 3
Views: 63

### Re: Electron Configurations

does 3d have higher energy than 4s? can someone explain why/why not?

Thanks!
Sun Nov 03, 2019 8:05 pm
Forum: Electronegativity
Topic: Electron affinity vs electronegativity
Replies: 4
Views: 61

### Re: Electron affinity vs electronegativity

Electron affinity is the energy released when an electron is added, while electronegativity is the tendency of an atom to attract electrons towards itself in a molecule of a compound.
Sun Nov 03, 2019 7:58 pm
Forum: Ionic & Covalent Bonds
Topic: Carbon Bonding
Replies: 5
Views: 59

### Re: Carbon Bonding

I believe that often times carbon prefers covalent bonds (sharing electrons)
Sun Nov 03, 2019 7:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Understanding Lyman and Balmer series
Replies: 3
Views: 66

### Re: Understanding Lyman and Balmer series

You know that n=1 is the final because the electrons are dropping from a higher energy level (initial) to the Lyman series, n=1, which is a lower energy level and the final state.
Sat Oct 26, 2019 10:08 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 5
Views: 83

### Re: Ionic and Covalent Bonds

Ionic bonds involve the transferring of electrons from a metal to a nonmetal.
Covalent bonds involve non metals sharing electrons to form covalent bonds.
Sat Oct 26, 2019 9:45 pm
Forum: Trends in The Periodic Table
Topic: Period 3 Elements
Replies: 2
Views: 28

### Re: Period 3 Elements

I believe this has to do with the larger size of period 3 elements and how they are able to accommodate more bonds.
Sat Oct 26, 2019 9:32 pm
Forum: Resonance Structures
Topic: Delocalized electrons
Replies: 2
Views: 24

### Re: Delocalized electrons

In resonance structures,
the electrons are delocalized. This means they are more spread out and evenly distributed.
Sat Oct 26, 2019 9:22 pm
Forum: Lewis Structures
Topic: Charges
Replies: 2
Views: 39

### Re: Charges

I don't know if I understand your question completely, but a cation is a positively charged molecule, therefore electrons have been removed, which is why it is positive. In an anion, electrons are added and to a molecule increasing the negative charge, making the molecule negative. When figuring out...
Sat Oct 26, 2019 9:16 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 6
Views: 63

### Re: Resonance

They are more stable because the electrons are delocalized.
Rather than being in a single lewis structure, they are more spread out and not bounded to a single bond.
This lowers the energy of the molecule, stabilizing it.
Sat Oct 19, 2019 1:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Midterm
Replies: 3
Views: 40

### Re: Midterm

I heard others say that their TA said it covers chemical bonding and quantum topics
Sat Oct 19, 2019 12:57 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 10
Views: 113

### Re: Nodal Planes

Can someone explain why s has no nodal plane? thanks!
Sat Oct 19, 2019 12:24 pm
Forum: Quantum Numbers and The H-Atom
Topic: Principal Quantum Number
Replies: 3
Views: 55

### Re: Principal Quantum Number

I agree with what was said above.

The Principle quantum level is the shell or energy level of an electron at ground state. At ground state electron's aren't excited and jumping energy levels.
Sat Oct 19, 2019 12:16 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisengberg Uncertainty Equation Meaning
Replies: 7
Views: 111

### Re: Heisengberg Uncertainty Equation Meaning

In the Heisenberg equation, what number would you plug in for delta X? and what does X stand for?
Sat Oct 19, 2019 12:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 5
Views: 90

### Re: Atomic Spectra

When the energy of the photon matches the energy of an electron that photon is emitted or absorbed.

when a high energy electron drops to lower energy level, the difference in energy is given off as a photon.
Sat Oct 19, 2019 12:00 pm
Forum: Properties of Light
Topic: Quantum equations
Replies: 5
Views: 64

### Quantum equations

Is velocity usually in nm or m? does it matter when using the equations if the question doesn't specify units?
Fri Oct 11, 2019 5:01 pm
Forum: Properties of Light
Topic: Converting units
Replies: 8
Views: 85

### Re: Converting units

A good tip to remember when converting units is to make sure they cancel until what you want is left. Set them up as ratios so that when you multiply terms the top and bottom cancel.
Fri Oct 11, 2019 4:47 pm
Forum: Properties of Light
Topic: Electric vs Magnetic Fields
Replies: 2
Views: 36

### Re: Electric vs Magnetic Fields

Magnetic fields are produced by electric currents. They are dipolar, meaning they have a north and south magnetic pole. Both electric and magnetic fields are made of photons.
Fri Oct 11, 2019 4:42 pm
Forum: Empirical & Molecular Formulas
Topic: empirical = molecular?
Replies: 15
Views: 578

### Re: empirical = molecular?

The empirical formula can be viewed as the smallest ratio of the molecular formula. If the molar mass of the empirical formula is the same as the molar mass of the molecular formula given in the question then they are the same.
Fri Oct 11, 2019 4:38 pm
Forum: Properties of Light
Topic: Quanta vs Photon
Replies: 4
Views: 56

### Re: Quanta vs Photon

A photon has the properties of both a wave and particle, a quantum doesn't. The photon is the quantum of electromagnetic radiation, or the basic unit of light. Quantum can be described as a measure of quantity but a photon is not about a measure of quantity. A photon is quantum but not all quanta ar...
Fri Oct 11, 2019 4:32 pm
Forum: Properties of Light
Topic: Energy Levels
Replies: 8
Views: 155

### Re: Energy Levels

The N=1 is known as the ground state. The gap between N=1 and N=2 is the largest, meaning it has the largest release of energy. The ultraviolent region is the largest release of energy.
Thu Oct 03, 2019 2:26 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 4
Views: 78

### Re: Sig Figs

I make sure my sigifigs are consistent all around. But if the problem gives a mass with specific sigfigs, I would try and match those.
Thu Oct 03, 2019 2:10 pm
Forum: Balancing Chemical Reactions
Topic: "Combustion" Term
Replies: 8
Views: 256

### Re: "Combustion" Term

Combustion refers to "burning."
In combustion reactions, oxygen is always a reactant that will yield carbon dioxide and water.
Thu Oct 03, 2019 2:02 pm
Forum: Empirical & Molecular Formulas
Topic: How to properly order moles of a compound
Replies: 2
Views: 45

### Re: How to properly order moles of a compound

I ordered the elements as they are listed in the book. So, C, H, N, then O.

This is also the order the book has in the answer key.
Thu Oct 03, 2019 1:54 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molar Mass Clarification
Replies: 3
Views: 45

### Re: Molar Mass Clarification

The molar mass of elements and compounds can be found from the periodic table.

For example:

C: 12.01g
O: 16.00g

CO2: 12.01g + 16.00(2) = 44.01g
Thu Oct 03, 2019 1:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Replies: 16
Views: 387

### Re: Avogadro's Number?

When you are asked to convert to formula units, atoms, or molecules, use avogadro's number.
Thu Oct 03, 2019 11:58 am
Forum: Limiting Reactant Calculations
Topic: Fundamentals M5 [ENDORSED]
Replies: 4
Views: 725

### Re: Fundamentals M5[ENDORSED]

How would you calculate the amount of excess BrF3?

I understand how to calculate the moles of each product left, but how would I calculate the moles of excess reactant?

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