Search found 66 matches
- 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: 599
Re: Effects of Compression
Yes, this affects molecules in the gas phase.
- Sun Mar 17, 2019 11:17 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q
- Replies: 6
- Views: 837
Re: Q
Nope, it only depends on the concentration/partial pressure.
- 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: 599
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.
- Sun Mar 17, 2019 10:05 am
- Forum: Calculating Work of Expansion
- Topic: Reversible vs irreversible
- Replies: 2
- Views: 556
Reversible vs irreversible
How do we know if work is reversible or irreversible?
- 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: 410
Re: Enthalpy At Constant Volume?
I believe so, because at constant volume work is zero so heat is equal to delta U (internal energy)
- Sat Mar 16, 2019 9:42 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Homework problem 7D1
- Replies: 5
- Views: 874
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...
- Sat Mar 16, 2019 9:40 pm
- Forum: Ideal Gases
- Topic: Nitrogen gas
- Replies: 5
- Views: 641
Nitrogen gas
Is nitrogen gas an ideal gas?
- Sat Mar 16, 2019 9:16 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 527744
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
Thankyou, Ryan Danis
- Sat Mar 16, 2019 9:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7468
Re: LYNDON'S PORK RAMEN REVIEW
These questions were very helpful for my understanding of electrochem especially. Thankyou!
- Fri Mar 15, 2019 6:58 pm
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 148176
Re: Reading the textbook
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...
- Fri Mar 15, 2019 6:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Approximation & Cubic Equations on Final
- Replies: 2
- Views: 502
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?
- Thu Mar 14, 2019 6:09 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre-Equilibrium Approach
- Replies: 3
- Views: 313
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.
- Thu Mar 14, 2019 6:03 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Yekan Final review slides and solutions 0312
- Replies: 8
- Views: 1217
Re: Yekan Final review slides and solutions 0312
These problems were very helpful for studying thermo, thanks!
- Wed Mar 13, 2019 4:20 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Homework problem 7D1
- Replies: 5
- Views: 874
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...
- 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: 592
Adding an Inert Gas
What is meant by an inert gas and why doesn't it cause a shift towards reactants or products?
- 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: 228
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...
- Wed Mar 13, 2019 1:48 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 2
- Replies: 3
- Views: 424
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.
- 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: 1861
Platinum in Cell Diagram
When and why do we add platinum to a cell diagram?
- Wed Mar 13, 2019 1:43 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: E cell
- Replies: 2
- Views: 267
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).
- 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: 1640
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 ...
- 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: 471
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...
- Thu Feb 28, 2019 3:01 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Finding n
- Replies: 12
- Views: 1095
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?)
- Thu Feb 28, 2019 2:59 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Potential Difference Conceptually
- Replies: 1
- Views: 188
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?
- Thu Feb 28, 2019 12:43 pm
- Forum: Balancing Redox Reactions
- Topic: 7th edition 6K.3.d.
- Replies: 1
- Views: 197
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.
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.
- Thu Feb 21, 2019 9:39 pm
- Forum: Calculating Work of Expansion
- Topic: Nonexpansion work vs expansion work
- Replies: 3
- Views: 836
Nonexpansion work vs expansion work
What is the difference between expansion work and non-expansion work?
- Thu Feb 21, 2019 9:32 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy Meaning
- Replies: 6
- Views: 739
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.
- 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: 476
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.
- 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: 158
Heat vs Enthalpy
Can someone explain to me why heat is not a state function even though enthalpy is a state function?
- Thu Jan 31, 2019 12:39 pm
- Forum: Calculating Work of Expansion
- Topic: Change in internal energy
- Replies: 3
- Views: 331
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!
- Wed Jan 30, 2019 4:12 pm
- Forum: Calculating Work of Expansion
- Topic: Change in internal energy
- Replies: 3
- Views: 331
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)
- Wed Jan 30, 2019 3:57 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.3 7th Ed
- Replies: 6
- Views: 530
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...
- 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: 1110
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.
- 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: 387
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...
- Thu Jan 10, 2019 10:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th Edition 5H.3
- Replies: 3
- Views: 906
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
I am confused about how to combine reactions in table 5G2 to determine the value of K. Thanks! I
- Tue Jan 08, 2019 11:29 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th Edition 5G.5 part c
- Replies: 2
- Views: 127
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...
- Sat Dec 08, 2018 3:48 pm
- Forum: Polyprotic Acids & Bases
- Topic: Significance of Polyprotic Acids & Bases
- Replies: 6
- Views: 955
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.
- Sat Dec 08, 2018 2:35 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Electronegativity & Acid Strength
- Replies: 2
- Views: 539
Electronegativity & Acid Strength
Can someone explain why electronegativity has an effect on the strength of acids? Thanks!
- Sat Dec 08, 2018 2:25 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: 7th edition 6C.17 [ENDORSED]
- Replies: 1
- Views: 186
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...
- Fri Dec 07, 2018 10:16 pm
- Forum: Biological Examples
- Topic: Function of cisplatin
- Replies: 1
- Views: 451
Re: Function of cisplatin
Cosplatin forms a coordination compound with DNA (bonds to guanine) stopping cell division.
- 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: 21088
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?
- Fri Dec 07, 2018 8:14 pm
- Forum: Amphoteric Compounds
- Topic: Difference between amphoteric and amphiprotic?
- Replies: 4
- Views: 875
Re: Difference between amphoteric and amphiprotic?
Amphoteric substances can function as either acids or bases. Amphiprotic substances can accept or donate H+.
- 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: 2834
Re: Determining polar and non polar molecules from a lewis structure
If the dipole moments cancel out, the molecule is non polar.
- Thu Dec 06, 2018 6:27 pm
- Forum: Lewis Acids & Bases
- Topic: BaO a Lewis acid ?
- Replies: 3
- Views: 551
Re: BaO a Lewis acid ?
BaO is basic since it's a metal oxide (Ba is in group 2).
- Thu Dec 06, 2018 4:55 pm
- Forum: Amphoteric Compounds
- Topic: Amphiteric compounds
- Replies: 1
- Views: 272
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?
- Thu Dec 06, 2018 3:35 pm
- Forum: Lewis Acids & Bases
- Topic: Identify the Salt Produced
- Replies: 1
- Views: 217
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...
- Tue Dec 04, 2018 2:44 pm
- Forum: Naming
- Topic: 9c.1 7th Edition
- Replies: 3
- Views: 172
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!
- Tue Dec 04, 2018 2:28 pm
- Forum: Naming
- Topic: 7th Edition 9C. 1
- Replies: 3
- Views: 317
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!
- 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: 390
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!
- Thu Nov 29, 2018 11:26 pm
- Forum: Hybridization
- Topic: Hybridization Notation
- Replies: 10
- Views: 909
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?
- Fri Nov 23, 2018 7:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Models and Resonance Structures
- Replies: 4
- Views: 1014
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...
- Fri Nov 23, 2018 4:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on the Central Atom
- Replies: 5
- Views: 520
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!!!
- Fri Nov 23, 2018 3:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on the Central Atom
- Replies: 5
- Views: 520
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...
- Fri Nov 02, 2018 2:29 pm
- Forum: Ionic & Covalent Bonds
- Topic: 7th edition 2A.1 c
- Replies: 1
- Views: 90
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!
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!
- Thu Nov 01, 2018 10:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent Bonds
- Replies: 18
- Views: 1776
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...
- Thu Nov 01, 2018 10:07 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration of Silver
- Replies: 1
- Views: 494
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?
- Thu Oct 25, 2018 11:02 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Nodal Planes and test 2
- Replies: 3
- Views: 303
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.
- Thu Oct 25, 2018 11:01 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum Numbers
- Replies: 3
- Views: 694
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.
- 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: 321
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...
- Tue Oct 23, 2018 11:15 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 6
- Views: 555
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?
- Tue Oct 23, 2018 11:12 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: m with subscript l
- Replies: 4
- Views: 553
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.
- Thu Oct 11, 2018 11:10 pm
- Forum: Properties of Light
- Topic: Problem number 1.23 [ENDORSED]
- Replies: 3
- Views: 369
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!
It shows the relationship between 1 eV = 1.60218x10^-19
Keep in mind that 1 keV = 1,000 eV when converting!
- Thu Oct 11, 2018 10:51 pm
- Forum: Properties of Light
- Topic: photons//energy//wavelengths
- Replies: 2
- Views: 250
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.
- Mon Oct 08, 2018 3:47 pm
- Forum: Properties of Light
- Topic: Problem 1A.15. 7th Edition p. 10
- Replies: 1
- Views: 131
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 ...
- Thu Oct 04, 2018 10:02 pm
- Forum: Balancing Chemical Reactions
- Topic: L.5 Mass
- Replies: 3
- Views: 370
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...
- Thu Oct 04, 2018 5:53 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Q G17 part b. (7th edition)
- Replies: 5
- Views: 1135
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 ...
- Sun Sep 30, 2018 6:25 pm
- Forum: Significant Figures
- Topic: Significant Figures
- Replies: 10
- Views: 2865
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...