Search found 66 matches

by Ryan Danis 1J
Sun Mar 17, 2019 11:18 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Effects of Compression
Replies: 5
Views: 135

Re: Effects of Compression

Yes, this affects molecules in the gas phase.
by Ryan Danis 1J
Sun Mar 17, 2019 11:17 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q
Replies: 6
Views: 139

Re: Q

Nope, it only depends on the concentration/partial pressure.
by Ryan Danis 1J
Sun Mar 17, 2019 10:19 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding an Inert Gas
Replies: 4
Views: 110

Re: Adding an Inert Gas

No, because an inert gas is not a part of the chemical equation used to find K, so K does not change when an inert gas is added.
by Ryan Danis 1J
Sun Mar 17, 2019 10:05 am
Forum: Calculating Work of Expansion
Topic: Reversible vs irreversible
Replies: 2
Views: 108

Reversible vs irreversible

How do we know if work is reversible or irreversible?
by Ryan Danis 1J
Sun Mar 17, 2019 9:19 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy At Constant Volume?
Replies: 2
Views: 105

Re: Enthalpy At Constant Volume?

I believe so, because at constant volume work is zero so heat is equal to delta U (internal energy)
by Ryan Danis 1J
Sat Mar 16, 2019 9:42 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Homework problem 7D1
Replies: 5
Views: 140

Re: Homework problem 7D1

Since it appeared in homework but it isn’t on the formula sheet, you probably need to memorize it if you don’t know how to derive it from the form of the Arrhenius equation given on the constants and equations sheet. (Assuming the constants and equations sheet on the class website will be the same a...
by Ryan Danis 1J
Sat Mar 16, 2019 9:40 pm
Forum: Ideal Gases
Topic: Nitrogen gas
Replies: 2
Views: 107

Nitrogen gas

Is nitrogen gas an ideal gas?
by Ryan Danis 1J
Sat Mar 16, 2019 9:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 202
Views: 66421

Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle, Thankyou for being such a great professor who truly cares about his students. I appreciate the time and effort put into the vast resources available. I learned so much chemistry in a short amount of time and feel excited going into the rest of the chem series.

Thankyou, Ryan Danis
by Ryan Danis 1J
Sat Mar 16, 2019 9:10 pm
Forum: Administrative Questions and Class Announcements
Topic: LYNDON'S PORK RAMEN REVIEW
Replies: 37
Views: 2351

Re: LYNDON'S PORK RAMEN REVIEW

These questions were very helpful for my understanding of electrochem especially. Thankyou!
by Ryan Danis 1J
Fri Mar 15, 2019 6:58 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 81
Views: 45376

Re: Reading the textbook [ENDORSED]

I find that when I read the textbook and take notes on the material I understand the concepts better. Also, there is occasionally a bit of information in the book that isn’t always covered in class (for instance, reducing and oxidizing power in electrochem) and this info can show up on tests. It tak...
by Ryan Danis 1J
Fri Mar 15, 2019 6:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Approximation & Cubic Equations on Final
Replies: 2
Views: 127

Approximation & Cubic Equations on Final

For the midterm, Prof Lavelle said there would be no cubic equations or approximations in the equilibrium problems. Will this be the case for the final as well?
by Ryan Danis 1J
Thu Mar 14, 2019 6:09 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-Equilibrium Approach
Replies: 3
Views: 51

Pre-Equilibrium Approach

For what type of question would I need to use the pre-equilibrium approach? I did not encounter any book problems where I had to use it.
by Ryan Danis 1J
Thu Mar 14, 2019 6:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Yekan Final review slides and solutions 0312
Replies: 8
Views: 366

Re: Yekan Final review slides and solutions 0312

These problems were very helpful for studying thermo, thanks!
by Ryan Danis 1J
Wed Mar 13, 2019 4:20 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Homework problem 7D1
Replies: 5
Views: 140

Re: Homework problem 7D1

It comes from the Arrhenius equation in the form of ln kr + ln A - (Ea/RT). When we are given two different temperatures, we can find the activation energy by using the Arrhenius equation for each temperature.: At temperature T1: ln kr1 = lnA - (Ea/RT1) At temperature T2: ln kr2 = lnA - (Ea/RT2) The...
by Ryan Danis 1J
Wed Mar 13, 2019 2:22 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding an Inert Gas
Replies: 4
Views: 118

Adding an Inert Gas

What is meant by an inert gas and why doesn't it cause a shift towards reactants or products?
by Ryan Danis 1J
Wed Mar 13, 2019 2:19 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2, Number 6 part b
Replies: 1
Views: 54

Test 2, Number 6 part b

Rank the following species in order of increasing oxidation power going from their third oxidation state to neutral: U3+, Cr3+, Al3+ The standard reduction potentials for each species are: U3+/U = -1.79V, Cr3+/Cr = -0.74V, Al3+/Al = -1.66 In the book it says that the more positive the cell potential...
by Ryan Danis 1J
Wed Mar 13, 2019 1:48 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2
Replies: 3
Views: 69

Re: Test 2

I believe it would be spontaneous because combustion is an exothermic process, so delta H would be negative. Because delta G = delta H - T delta S, and delta H is negative, delta G should be negative. When delta G is negative, the reaction is spontaneous.
by Ryan Danis 1J
Wed Mar 13, 2019 1:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum in Cell Diagram
Replies: 7
Views: 120

Platinum in Cell Diagram

When and why do we add platinum to a cell diagram?
by Ryan Danis 1J
Wed Mar 13, 2019 1:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E cell
Replies: 2
Views: 50

Re: E cell

I believe that in a galvanic cell the overall Ecell is positive so that would mean the larger Ecell is on the right (cathode).
by Ryan Danis 1J
Tue Mar 12, 2019 10:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: When to add H+ and H20 to the Cell Diagram
Replies: 2
Views: 47

When to add H+ and H20 to the Cell Diagram

Sometimes in a cell diagram, H+ and/or H20 are next to an element in a cell diagram separate by a comma. For example, from test 6: Balanced Equation: 2NO3-(aq) + 4H+ (aq) + Co (s) -> NO3- (aq) + 2H20 (l) + 2CO^3+ (aq) Co(s) I Co^2+ (aq) II NO31 (aq), H+ I NO2(g) I pt (s) How come H+ is added to the ...
by Ryan Danis 1J
Sun Mar 03, 2019 4:12 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Which Reduction potential of Water to use in Electrolysis
Replies: 1
Views: 109

Which Reduction potential of Water to use in Electrolysis

In 7th edition chapter 6.O, the exercises tell use to base our answers off of the potentials in the appendix with the exception of the reduction/oxidation of water at pH=7: 2H2O(l) + 2e- -> H2(g) + 2OH-(aq). E = -0.42V at pH=7 O2(g) + 4H+(aq) + 4e- -> 2H2O(l). E = +0.82 at pH=7 Which potential of wa...
by Ryan Danis 1J
Thu Feb 28, 2019 3:01 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding n
Replies: 12
Views: 187

Finding n

Is n just the number of electrons that appear on either side of each half reaction (ie: amount of electrons added to the oxidation side, that are then transferred from anode to cathode?)
by Ryan Danis 1J
Thu Feb 28, 2019 2:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Potential Difference Conceptually
Replies: 1
Views: 25

Potential Difference Conceptually

I understand how to find/use cell potential using the equations, but I am struggling to conceptualize what potential difference actually is. Can someone describe what potential difference is conceptually?
by Ryan Danis 1J
Thu Feb 28, 2019 12:43 pm
Forum: Balancing Redox Reactions
Topic: 7th edition 6K.3.d.
Replies: 1
Views: 36

7th edition 6K.3.d.

This question asks to balance the following redox reaction:

Reaction of Chlorine in water
Cl2(g) -> HClO(aq) + Cl2(g)

I am confused because it appears that Cl is being oxidized from 0 (in CL2) to +1 (in HCLO), but I cannot find what is being reduced.
by Ryan Danis 1J
Thu Feb 21, 2019 9:39 pm
Forum: Calculating Work of Expansion
Topic: Nonexpansion work vs expansion work
Replies: 3
Views: 127

Nonexpansion work vs expansion work

What is the difference between expansion work and non-expansion work?
by Ryan Danis 1J
Thu Feb 21, 2019 9:32 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Meaning
Replies: 6
Views: 114

Re: Gibbs Free Energy Meaning

Gibbs free energy is the energy of a system that is free to do work at constant pressure and temperature. As entropy increases, spotenaity increase. Because G=H-TS, as S increases, G decreases, so as G decreases spontaneity increases.
by Ryan Danis 1J
Mon Feb 11, 2019 3:48 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Equation for temperature change, 4F.11
Replies: 4
Views: 88

Re: Equation for temperature change, 4F.11

I faced the same problem and was confused why I could get neither the equation in the solutions manual via manipulating other equations nor the answer in the book. Must be an error in the 7th edition solutions and solution manual unless anybody else has an explanation.
by Ryan Danis 1J
Wed Feb 06, 2019 1:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heat vs Enthalpy
Replies: 1
Views: 39

Heat vs Enthalpy

Can someone explain to me why heat is not a state function even though enthalpy is a state function?
by Ryan Danis 1J
Thu Jan 31, 2019 12:39 pm
Forum: Calculating Work of Expansion
Topic: Change in internal energy
Replies: 3
Views: 59

Re: Change in internal energy

So the answer is 28J! The back of the book said the answer was 8J so it must be a typo, no wonder I was so confused. Thanks for your explanation!
by Ryan Danis 1J
Wed Jan 30, 2019 4:12 pm
Forum: Calculating Work of Expansion
Topic: Change in internal energy
Replies: 3
Views: 59

Change in internal energy

How do I calculate the change in internal energy of a system if the amount of heat transferred is not given? (7th edition 4A.3 part c)
by Ryan Danis 1J
Wed Jan 30, 2019 3:57 pm
Forum: Calculating Work of Expansion
Topic: 4A.3 7th Ed
Replies: 6
Views: 76

Re: 4A.3 7th Ed

I was having some trouble with this problem as well and the above replies have helped (I wasn’t squaring r or converting to liters). However I have one question. How come the work here is negative since it appears to be work done on the system instead of the system doing work? Is the system here the...
by Ryan Danis 1J
Tue Jan 22, 2019 9:06 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic vs Endothermic
Replies: 4
Views: 73

Re: Exothermic vs Endothermic

Usually delta H is given and you can tell by its sign. If delta H positive it’s endothermic, if delta H is negative it’s exothermic.
by Ryan Danis 1J
Tue Jan 22, 2019 9:01 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 7th edition 5J.5 part b
Replies: 3
Views: 84

7th edition 5J.5 part b

This question asks whether reactants or products will be favored by an increase in pressure (resulting from compression) on the equilibria. b. H2O(g)+C(s) <-> H2(g)+CO(g) I understood parts a,c,d,e because when pressure increases, the side with the fewer number of gas molecules is favored because it...
by Ryan Danis 1J
Thu Jan 10, 2019 10:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 7th Edition 5H.3
Replies: 3
Views: 68

7th Edition 5H.3

This question says ‘Use the information in table 5G.2 to determine the value of K at 300 K for the reaction 2BrCl(g)+H2(g) <-> Br2(g)+2HCl(g).

I am confused about how to combine reactions in table 5G2 to determine the value of K. Thanks! I
by Ryan Danis 1J
Tue Jan 08, 2019 11:29 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 7th Edition 5G.5 part c
Replies: 2
Views: 45

7th Edition 5G.5 part c

Problem 5G.5 shows a series of flasks containing the diatomic molecule, X2, with each flask showing it's dissociation over time. The first flask shows 11 X2 molecules. In the third flask, when the dissociation of X2 has reached equilibrium, there are 5 X2 molecules and 12 X atoms. Thus, 54.5% of the...
by Ryan Danis 1J
Sat Dec 08, 2018 3:48 pm
Forum: Polyprotic Acids & Bases
Topic: Significance of Polyprotic Acids & Bases
Replies: 6
Views: 171

Re: Significance of Polyprotic Acids & Bases

One example of the significance of polyprotic acids and bases is how the oceans help maintain a constant concentration of carbon dioxide in the atmosphere. Because carbonic is a polyprotic acid, it can successively donate protons, so when it reacts with water, it donates H+ to water reducing acidity.
by Ryan Danis 1J
Sat Dec 08, 2018 2:35 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Electronegativity & Acid Strength
Replies: 2
Views: 58

Electronegativity & Acid Strength

Can someone explain why electronegativity has an effect on the strength of acids? Thanks!
by Ryan Danis 1J
Sat Dec 08, 2018 2:25 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 7th edition 6C.17 [ENDORSED]
Replies: 1
Views: 72

7th edition 6C.17 [ENDORSED]

When reading this question (which is the stronger base, the hypobromite ion or morphine) I was confused because the sections we were supposed to read (6C.3 - 6C.4) only talked about the strength of acids in terms of trends. However, the answer uses the value of pKb to say that BrO- is the stronger b...
by Ryan Danis 1J
Fri Dec 07, 2018 10:16 pm
Forum: Biological Examples
Topic: Function of cisplatin
Replies: 1
Views: 109

Re: Function of cisplatin

Cosplatin forms a coordination compound with DNA (bonds to guanine) stopping cell division.
by Ryan Danis 1J
Fri Dec 07, 2018 8:48 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 4905

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

On question 38, how come the LDF’s are the determining factor instead of dipole-dipole in determining the boiling point?
by Ryan Danis 1J
Fri Dec 07, 2018 8:14 pm
Forum: Amphoteric Compounds
Topic: Difference between amphoteric and amphiprotic?
Replies: 4
Views: 97

Re: Difference between amphoteric and amphiprotic?

Amphoteric substances can function as either acids or bases. Amphiprotic substances can accept or donate H+.
by Ryan Danis 1J
Fri Dec 07, 2018 8:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polar and non polar molecules from a lewis structure
Replies: 8
Views: 145

Re: Determining polar and non polar molecules from a lewis structure

If the dipole moments cancel out, the molecule is non polar.
by Ryan Danis 1J
Thu Dec 06, 2018 6:27 pm
Forum: Lewis Acids & Bases
Topic: BaO a Lewis acid ?
Replies: 3
Views: 94

Re: BaO a Lewis acid ?

BaO is basic since it's a metal oxide (Ba is in group 2).
by Ryan Danis 1J
Thu Dec 06, 2018 4:55 pm
Forum: Amphoteric Compounds
Topic: Amphiteric compounds
Replies: 1
Views: 56

Amphiteric compounds

Do we need to know how to tell if a compound is amphoteric, or do we just need to memorize the amphoteric oxides?
by Ryan Danis 1J
Thu Dec 06, 2018 3:35 pm
Forum: Lewis Acids & Bases
Topic: Identify the Salt Produced
Replies: 1
Views: 66

Identify the Salt Produced

Question J. 9 part b in the 7th edition asks us to identify the salt produced from the acid-base neutralization reaction between ammonia and phosphoric acid. I was able to identify the salt produced, but not in the right quantity. I first wrote out the balanced equation as NH3 (aq) + H3PO4 (aq) -> N...
by Ryan Danis 1J
Tue Dec 04, 2018 2:44 pm
Forum: Naming
Topic: 9c.1 7th Edition
Replies: 3
Views: 34

Re: 9c.1 7th Edition

I was just about to ask why in parts b and d, the cobalt was simply stated as cobalt and not cobaltate in part c. Now I know that’s it’s because we only use the ate ending if the ion is negative. Thanks!
by Ryan Danis 1J
Tue Dec 04, 2018 2:28 pm
Forum: Naming
Topic: 7th Edition 9C. 1
Replies: 3
Views: 66

7th Edition 9C. 1

On question 1a, the name of the coordination compound of [Fe(CN)6]4- is hexacyanoferrate (II) ion. How come the CN is denoted as cyano instead of cyanido in the name of the compound? Thanks!
by Ryan Danis 1J
Fri Nov 30, 2018 12:17 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: 7th edition 3F. Question 3 part d.
Replies: 2
Views: 72

7th edition 3F. Question 3 part d.

Question 3 says to identify the types of IMF’s between molecules of the following substances. Part d gives the molecule SO2. The answer says that only hydrogen bonding and dipole-dipole forces may arise. How come London forces do not apply here? Thanks!
by Ryan Danis 1J
Thu Nov 29, 2018 11:26 pm
Forum: Hybridization
Topic: Hybridization Notation
Replies: 10
Views: 179

Hybridization Notation

If there is a molecule with let’s say dsp3 hybridization does it matter if we put the d first? Or can we say sp3d?
by Ryan Danis 1J
Fri Nov 23, 2018 7:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Models and Resonance Structures
Replies: 4
Views: 86

Re: VSEPR Models and Resonance Structures

For Lewis structures, it is best to consider resonance (resonance can help us determine bond angles). For the VSEPR model, resonance does not matter because each resonance structure has the same amount of regions of electron density. Moreover, double and triple bonds act the same as a single bond in...
by Ryan Danis 1J
Fri Nov 23, 2018 4:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs on the Central Atom
Replies: 5
Views: 97

Re: Lone Pairs on the Central Atom

Your explanation makes a lot of sense. So the lone pairs actually do affect the molecular shape by influencing the arrangement of the atoms, while only the atoms are used to then name the shape. The way the book explained it tripped me up. Thankyou!!!
by Ryan Danis 1J
Fri Nov 23, 2018 3:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs on the Central Atom
Replies: 5
Views: 97

Lone Pairs on the Central Atom

I am a bit confused about how/why the lone pairs on a central atom affect (or don’t affect) the VSEPR model. The book says that if lone pairs are present, only the electron arrangement is affected, but not the shape. Does this mean that a Lewis structure be an example of an electron arrangement of a...
by Ryan Danis 1J
Fri Nov 02, 2018 2:29 pm
Forum: Ionic & Covalent Bonds
Topic: 7th edition 2A.1 c
Replies: 1
Views: 28

7th edition 2A.1 c

Question 2A.1 c. asks for the amount of valence electrons in Mn.

I am confused about how to find the amount of valence electrons for elements in the d-block. Can someone explain this and how I would apply it to finding the number of valence e- in Mn? Thanks!
by Ryan Danis 1J
Thu Nov 01, 2018 10:13 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent Bonds
Replies: 18
Views: 443

Re: Ionic vs Covalent Bonds

In ionic bonds, metals and non metals either gain or lose electrons to achieve the electron configuration of the nearest noble gas. Thus, the transfer of electrons leads to an octet of electrons (although there is an exception for H, He, Li, and Be). Main group metals form cations. They lose s and p...
by Ryan Danis 1J
Thu Nov 01, 2018 10:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration of Silver
Replies: 1
Views: 124

Electron Configuration of Silver

I am confused about the filling of d-orbitals in electron configurations. How does silver have a 4d10 5s1 electron configuration when it is in period 11 of the periodic table? Why isn't it 4p9 5s2?
by Ryan Danis 1J
Thu Oct 25, 2018 11:02 pm
Forum: Quantum Numbers and The H-Atom
Topic: Nodal Planes and test 2
Replies: 3
Views: 94

Re: Nodal Planes and test 2

Yes. Also remember that using the fact that s has 0 nodal planes, p has 1 nodal plane, and d has 2 nodal planes, we can predict that f orbitals have 3 nodal planes.
by Ryan Danis 1J
Thu Oct 25, 2018 11:01 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Numbers
Replies: 3
Views: 73

Re: Quantum Numbers

n, l, and ml are always integers. Keep in mind that n can never be 0, l can never be negative but can be 0 and positive, and ml can be negative, 0, and positive.
by Ryan Danis 1J
Thu Oct 25, 2018 10:48 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.23 b and d, 7th edition
Replies: 1
Views: 74

1D.23 b and d, 7th edition

Question 1D.23 asks, "How many orbitals can have the following quantum numbers in an atom?" a. n=2, l=1 b. n=4, l=2, ml=-2 c. n=2 d. n=3, l=2, ml=+1 I understand that (a.) corresponds to a p subshell which has 3 orbitals, and that (c.) both p and s orbitals can have the quantum number 2 wh...
by Ryan Danis 1J
Tue Oct 23, 2018 11:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 6
Views: 141

Nodal Planes

So the book says that nodal planes separate the two lobes of a p-orbital where the wave function is 0. How come s orbitals do not have a nodal plane?
by Ryan Danis 1J
Tue Oct 23, 2018 11:12 pm
Forum: Quantum Numbers and The H-Atom
Topic: m with subscript l
Replies: 4
Views: 86

Re: m with subscript l

m subscript l is the third quantum number known as the magnetic quantum number. It distinguishes the the individual orbitals within a subshell (tells us the number of orbitals and their orientation. It can have the values l, l-1, ... , -l.
by Ryan Danis 1J
Thu Oct 11, 2018 11:10 pm
Forum: Properties of Light
Topic: Problem number 1.23 [ENDORSED]
Replies: 3
Views: 73

Re: Problem number 1.23 [ENDORSED]

The back of the textbook has a table labeled "RELATIONS BETWEEN UNITS"

It shows the relationship between 1 eV = 1.60218x10^-19

Keep in mind that 1 keV = 1,000 eV when converting!
by Ryan Danis 1J
Thu Oct 11, 2018 10:51 pm
Forum: Properties of Light
Topic: photons//energy//wavelengths
Replies: 2
Views: 81

Re: photons//energy//wavelengths

First I converted keV to Joules using the table in the constants in the back of the book. From there I found the frequency using E=hv. Then I used c=lambda(v) to find the wavelength.
by Ryan Danis 1J
Mon Oct 08, 2018 3:47 pm
Forum: Properties of Light
Topic: Problem 1A.15. 7th Edition p. 10
Replies: 1
Views: 64

Problem 1A.15. 7th Edition p. 10

I am stuck on question 1A.15. It asks "In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line." So the first thing I did ...
by Ryan Danis 1J
Thu Oct 04, 2018 10:02 pm
Forum: Balancing Chemical Reactions
Topic: L.5 Mass
Replies: 3
Views: 74

Re: L.5 Mass

First you have to use the molar mass of NH4ClO4 to convert 1.325 kg NH4ClO4 into moles of NH4ClO4 (keep in mind you have that you have to convert kg to g). From there you multiply the moles of NH4ClO4 by the molar ratio of Al:NH4ClO4. You find the molar ratio by looking at the coefficients of the ba...
by Ryan Danis 1J
Thu Oct 04, 2018 5:53 pm
Forum: Molarity, Solutions, Dilutions
Topic: Q G17 part b. (7th edition)
Replies: 5
Views: 109

Q G17 part b. (7th edition)

Question G 17 asks: a. Determine the mass of anhydrous copper(II) sulfate that must be used to prepare 250 mL of 0.20 M CuS04 (aq). b. Determine the mass of CuSO4 x 5(H20) that must be used to prepare 250mL of 0.20 M CuSO4 (aq0. I was able to solve part a by finding the amount of moles of CuSO4 and ...
by Ryan Danis 1J
Sun Sep 30, 2018 6:25 pm
Forum: Significant Figures
Topic: Significant Figures
Replies: 10
Views: 236

Re: Significant Figures

Significant figures only need to be applied in the final answer. In your example with the number of given sig figs as 2, but the molar mass having 4 sig figs, I recommend keeping the 4 molar mass sig figs throughout the calculation, and then giving your answer with 2 sig figs. Keeping all sig figs t...

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