Search found 66 matches
- Thu Jun 14, 2018 10:30 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: HW 17.33
- Replies: 6
- Views: 790
Re: HW 17.33
No the lone pairs on the double bonded O won't bind with the metal because that would give O three bonds (one double with C and one single with the metal) and one lone pair, and thus a formal charge of : FC=6-2-3=+1 which is less stable than it was when O was just bound to the C with a double bond a...
- Thu Jun 14, 2018 10:25 am
- Forum: Biological Examples
- Topic: Cisplatin shape
- Replies: 2
- Views: 448
Re: Cisplatin shape
Thank you so much! :)
- Tue Jun 12, 2018 9:57 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: HW 17.33
- Replies: 6
- Views: 790
Re: HW 17.33
Thank you! :)
- Tue Jun 12, 2018 9:55 am
- Forum: Biological Examples
- Topic: Cisplatin shape
- Replies: 2
- Views: 448
Cisplatin shape
Hi!
I know that if a transition metal is bound to 4 ligands, its shape could either be square planar or tetrahedral. How do I distinguish between these two shapes? And what would be the shape of cisplatin, tetrahedral or square planar?
Thank you!! :)
Anna De Schutter - section 1A
I know that if a transition metal is bound to 4 ligands, its shape could either be square planar or tetrahedral. How do I distinguish between these two shapes? And what would be the shape of cisplatin, tetrahedral or square planar?
Thank you!! :)
Anna De Schutter - section 1A
- Sun Jun 10, 2018 11:54 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Confusion on Friday's lecture [ENDORSED]
- Replies: 2
- Views: 474
Re: Confusion on Friday's lecture [ENDORSED]
Thank you Dr. Lavelle! :)
- Sun Jun 10, 2018 11:53 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: HW 17.33
- Replies: 6
- Views: 790
HW 17.33
Hi! I'm a bit confused about the answers given in the solutions manual regarding problem 17.33. For part a, we consider HN(CH2CH2NH2)2 and the solutions manual says it is tridentate. For part b however (CO3 2-), the solutions manual says it can be monodentate or bidentate. I understand why CO3 2- ca...
- Sun Jun 10, 2018 4:36 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Confusion on Friday's lecture [ENDORSED]
- Replies: 2
- Views: 474
Confusion on Friday's lecture [ENDORSED]
Hi! For last Friday's lecture I wrote down in my notes that: Cl- is "good on its own" in a solution as shown by the equation HCl --> H+ + Cl- I'm a bit confused by this though, how can we know Cl- won't affect the reaction through this equation? Is this also why Cl- doesn't affect the pH o...
- Tue Jun 05, 2018 3:47 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Problem 17.29
- Replies: 3
- Views: 359
Re: Problem 17.29
I had my discussion section today, and my TA explained to me how to find the charge of a ligand :) She told us that we needed to calculate the formal charge of the atom of the ligand bound to the transition metal. So for example for the coordination compound [Co(en)2(Cl)2)]*, we need to calculate th...
- Mon Jun 04, 2018 11:28 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 17.33 - Polydentate ligands
- Replies: 1
- Views: 320
Re: 17.33 - Polydentate ligands
Also, if it is true that double bonds don't count as ligands, why can (CO3)2- be a monodentate or a bidentate (it has one double bonded O and two single bonded O), but oxalate (C2O4)2- can only be a bidentate (it has two double bonded O's and two single bonded O's)? Can't (C2O4)2- also be a monodent...
- Mon Jun 04, 2018 11:23 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Problem 17.33
- Replies: 2
- Views: 286
Re: Problem 17.33
Thank you!! :)
- Mon Jun 04, 2018 10:55 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Problem 17.29
- Replies: 3
- Views: 359
Problem 17.29
Hi! In problem 17.29, we need to determine the oxidation number of each metal. In the solutions manual we are given the formula: (#metal atoms)(oxidation number of the metal) + summation sign(# each ligand)(charge of each ligand)=charge of the ion I was wondering, how to we determine the charge of e...
- Mon Jun 04, 2018 10:37 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Problem 17.33
- Replies: 2
- Views: 286
Problem 17.33
Hi! I'm a bit confused on how to do problem 17.33. For 17.33 a for example, I thought HN(CH2CH2NH2)2 would be tridentate (which it is!) because there are three available lone pairs, one on each nitrogen. But then for 17.33 c, where we are given H2O, the solutions manual says it is monodentate. I jus...
- Tue May 29, 2018 8:17 am
- Forum: Dipole Moments
- Topic: Class question: polarizability and boiling point
- Replies: 2
- Views: 463
Re: Class question: polarizability and boiling point
That makes a lot of sense, thank you! :)
- Mon May 28, 2018 10:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.13 part c
- Replies: 4
- Views: 432
Re: HW 4.13 part c
Yeah I looked at the solutions manual error document on the website but it didn't show an error for 4.13 so I'm confused as to what I'm doing wrong :( Do you see any errors in my reasoning? Thank you!! :)
- Mon May 28, 2018 10:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.19 part b and d
- Replies: 3
- Views: 497
HW 4.19 part b and d
Hi! For the (CH3)2Be molecule, the shape is said to be tetrahedral around the carbon atoms in the solutions manual. Could I also say that the shape of the whole molecule is linear because we have Be in the middle and a CH3 on either side? Or would that be wrong? Also, for the SnCl2 molecule, I drew ...
- Mon May 28, 2018 10:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.13 part c
- Replies: 4
- Views: 432
HW 4.13 part c
Hi! Isn't the Lewis structure for IO3- an I with two O around it with double bonds and one O with a single bond instead of the one shown in the solutions manual (where I is attached to three O's, each with a single bond)? The structure shown in the solutions manual would give the formal charges: I =...
- Mon May 28, 2018 9:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.3 - structure of CH2F2
- Replies: 2
- Views: 706
Re: HW 4.3 - structure of CH2F2
Oki, thank you! :)
- Mon May 28, 2018 9:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular shape of H2O
- Replies: 2
- Views: 361
Re: Molecular shape of H2O
Thank you!! :)
- Mon May 28, 2018 9:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.3 - structure of CH2F2
- Replies: 2
- Views: 706
HW 4.3 - structure of CH2F2
Hi! In homework 4.3 we are asked to draw the structure of CH2F2. I was going to draw the Lewis structure the way we did it before (with a 90 degrees angle between each three consecutive atoms), but in the solutions manual, the structure drawn shows on H atom as being in front of the other (with the ...
- Mon May 28, 2018 5:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular shape of H2O
- Replies: 2
- Views: 361
Molecular shape of H2O
Hi!
Last Wednesday in class we said that water doesn't have a linear shape because of its two lone pairs of electrons. What is the name of a molecule that has the notation AX2E2, such as H2O?
Thank you!
Anna De Schutter - section 1A
Last Wednesday in class we said that water doesn't have a linear shape because of its two lone pairs of electrons. What is the name of a molecule that has the notation AX2E2, such as H2O?
Thank you!
Anna De Schutter - section 1A
- Mon May 28, 2018 3:00 pm
- Forum: Dipole Moments
- Topic: Class question: polarizability and boiling point
- Replies: 2
- Views: 463
Class question: polarizability and boiling point
Hi! In class we talked about how the interaction potential energy for induced dipole - induced dipole interactions is proportional to (polarizability 1 * polarizability 2)/distance^6 We also said that the polarizability depends on the size of the atom and the number of electrons, with an increase in...
- Sun May 27, 2018 7:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 1
- Views: 263
Re: Bond Angles
Hi! Is there a specific hw problem you had in mind that showed this? The only reason I can think of why we would say less than a certain bond angle instead of the actual value is because of the presence of lone pair electrons. We said in class, repulsion strength: lone pair - lone pair > lone pair -...
- Sun May 27, 2018 3:55 pm
- Forum: Octet Exceptions
- Topic: Question 3.63 part b
- Replies: 2
- Views: 431
Re: Question 3.63 part b
Hi! Dr. Lavelle also talked about during last Friday's lecture when he said that the reason Xe can interact with other atoms even if it is a noble gas is because it is a very large atom. As a result, Xenon doesn't hold on to its electrons very well and sharing electrons with other atoms, such as F i...
- Sun May 27, 2018 3:48 pm
- Forum: Octet Exceptions
- Topic: Help on 3.59 in homework?
- Replies: 2
- Views: 400
Re: Help on 3.59 in homework?
Hi!
I also had the same problem as you, but then Dr. Lavelle referred me to one of his posts which was very helpful!
Here it is:
viewtopic.php?f=33&t=31699&p=100750
Hope this helps! :)
Anna De Schutter - section 1A
I also had the same problem as you, but then Dr. Lavelle referred me to one of his posts which was very helpful!
Here it is:
viewtopic.php?f=33&t=31699&p=100750
Hope this helps! :)
Anna De Schutter - section 1A
- Tue May 22, 2018 2:07 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: HW 3.83
- Replies: 7
- Views: 3098
Re: HW 3.83
Another way to look at it is that N is less electronegative than O which is another reason why N3- has a higher polarizability than O2- because the polarizability of an anion increases as its electronegativity decreases. What I don't really understand is why do smaller cations have a higher polarizi...
- Mon May 21, 2018 5:34 pm
- Forum: Octet Exceptions
- Topic: He, Li and Be
- Replies: 3
- Views: 542
He, Li and Be
Hi!
I'm a bit confused, how are He, Li and Be exceptions to the octet rule? If they don't aim to have 8 valence electrons, what do they do then?
Thank you!
Anna De Schutter - section 1A
I'm a bit confused, how are He, Li and Be exceptions to the octet rule? If they don't aim to have 8 valence electrons, what do they do then?
Thank you!
Anna De Schutter - section 1A
- Sun May 20, 2018 9:36 pm
- Forum: Lewis Structures
- Topic: chapter 3 hw #57 question
- Replies: 5
- Views: 705
Re: chapter 3 hw #57 question
Would we be given a chart that tells us the electronegativity of each element in order to solve this question? Or is there another way to know that O is more electronegative than Cl?
Thank you! :)
Thank you! :)
- Sun May 20, 2018 9:34 pm
- Forum: Dipole Moments
- Topic: Meaning of a dipole
- Replies: 7
- Views: 783
Re: Meaning of a dipole
And when you say separation of charges in the molecule do you mean where the electrons are located?
Thank you! :)
Thank you! :)
- Sun May 20, 2018 9:20 pm
- Forum: Dipole Moments
- Topic: Meaning of a dipole
- Replies: 7
- Views: 783
Meaning of a dipole
I'm a bit confused, what does the term dipole mean? And is it different from a dipole moment?
Thank you so much! :)
Anna De Schutter - section 1A
Thank you so much! :)
Anna De Schutter - section 1A
- Sun May 20, 2018 7:14 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic compound
- Replies: 2
- Views: 288
Re: Ionic compound
Thank you! :)
- Sun May 20, 2018 4:24 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic compound
- Replies: 2
- Views: 288
Ionic compound
In class we said that when we form an ionic compound, we transfer the electrons from a metal to a nonmetal. I just want to make sure are the metalloids: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po) and then everything to the right of it is a ...
- Sun May 20, 2018 3:10 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.59a
- Replies: 2
- Views: 285
Re: 3.59a
I had the same question, because when I calculated the formal charges of chlorine and oxygen in the solution's manual configuration I got: Cl: 7valence electrons - 5 lone pair electrons - 0.5*2 bonding electrons = +1 O: 6valence electrons -6 lone pair electrons - 0.5*2bonding electrons = -0.5 Wherea...
- Fri May 18, 2018 12:53 am
- Forum: Ionic & Covalent Bonds
- Topic: Help on 3.23
- Replies: 2
- Views: 355
Re: Help on 3.23
To add on to that, the reason chlorine would hypothetically gain one electron or lose 7 electrons is so that it has the electron configuration of a noble gas. if chlorine gains one electron, it would have the electron configuration of argon: [Ar] if chlorine loses 7 electrons, it would have the elec...
- Sun May 13, 2018 2:50 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.33
- Replies: 5
- Views: 613
Re: 3.33
I think that another way you can determine which element has the lowest ionization energy between two elements that are in two different rows or groups is to use the concept of diagonal relationship which states that elements diagonal to each other (one period down and one group to the right) have v...
- Sun May 13, 2018 2:42 pm
- Forum: Lewis Structures
- Topic: formal charge?
- Replies: 3
- Views: 2407
Re: formal charge?
Hi! To answer your first question (how to do the Lewis structure for CCl4), the way I do it is I first count the number of valence electrons present in the molecule. So in CCl4, carbon has 4 valence electrons and chlorine has 7 valence electrons. Because there are four Cl in the molecule CCl4, the t...
- Sun May 13, 2018 2:11 pm
- Forum: Ionic & Covalent Bonds
- Topic: Main group metals
- Replies: 2
- Views: 404
Re: Main group metals
Thank you that helps a lot! :)
- Fri May 11, 2018 6:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Main group metals
- Replies: 2
- Views: 404
Main group metals
Hi! During class (Wednesday of week 5) we talked about main group metals and how they form cations by losing their s and p valence electrons. As a result, they adopt the electron configuration of the preceding inert-gas atom. I'm a bit confused, what does main group metals mean? Moreover, Dr. Lavell...
- Thu May 10, 2018 3:31 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2.55 - what does valence-shell configuration mean?
- Replies: 3
- Views: 568
Re: 2.55 - what does valence-shell configuration mean?
Thank you!! :)
- Mon May 07, 2018 10:08 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2.55 - what does valence-shell configuration mean?
- Replies: 3
- Views: 568
2.55 - what does valence-shell configuration mean?
Hi! Problem 2.55 says: "Give the notation for the valence-shell configuration (including the outermost d-electrons)". I'm a bit confused, what does valence-shell configuration mean? For example, for part b it asks us to give the valence-shell configuration of group 15 elements and I was ju...
- Sun May 06, 2018 2:32 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: homework 2.43 part e [ENDORSED]
- Replies: 8
- Views: 931
Re: homework 2.43 part e [ENDORSED]
But why is it 5d^4 6s^2 and not 5d^5 6s^1? I thought it was more stable to have d^5 than d^4 (as well as d^10 instead of d^9)? Also are we expected to know how to include the f-block in electron configurations? I'm not sure but I thought we had to know how to do electron configurations of the s-bloc...
- Sun May 06, 2018 2:28 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Confusion with problem 1.57 [ENDORSED]
- Replies: 4
- Views: 950
Re: Confusion with problem 1.57 [ENDORSED]
That makes a lot of sense! Thank you so much! :)
- Sun May 06, 2018 12:14 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Confusion with problem 1.57 [ENDORSED]
- Replies: 4
- Views: 950
Confusion with problem 1.57 [ENDORSED]
Hi! Problem 1.57 says: "Lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line in the series?" I thought because in the Balmer series we are starting at n=2, that the next line in the series would be n=...
- Sat May 05, 2018 11:25 am
- Forum: Photoelectric Effect
- Topic: Midterm Review Q4
- Replies: 2
- Views: 403
Re: Midterm Review Q4
Hi! The way I answered that question is by saying that the photoelectric experiment shifted our perception from seeing light behaving only as a wave to seeing it as composed of packets of energy called photons as well. Indeed, the photoelectric experiment didn't match the wavelike properties of ligh...
- Sat May 05, 2018 11:02 am
- Forum: Trends in The Periodic Table
- Topic: Removing the 2nd electron is always harder [ENDORSED]
- Replies: 5
- Views: 1556
Re: Removing the 2nd electron is always harder [ENDORSED]
Thank you Beverly! :)
- Wed May 02, 2018 9:36 pm
- Forum: Trends in The Periodic Table
- Topic: Removing the 2nd electron is always harder [ENDORSED]
- Replies: 5
- Views: 1556
Re: Removing the 2nd electron is always harder [ENDORSED]
I'm still a bit confused, like if we take away one electron, the second electron could still be on the outermost shell right? Like for oxygen for example, there are 6 electrons in n=2 so wouldn't removing one electron mean that the second electron we remove is still on the outermost shell (n=2)? Why...
- Wed May 02, 2018 4:25 pm
- Forum: Trends in The Periodic Table
- Topic: lecture question 5/2
- Replies: 3
- Views: 342
Re: lecture question 5/2
Hi! I'm not too sure if it was called shell attraction, but how I understood it is that across a period, the atomic radius decreases. This is because across a period, we still remain in the same shell (n=1 for example, or n=2, etc.), yet the number of protons increases. Thus, the electrons are more ...
- Wed May 02, 2018 4:19 pm
- Forum: Trends in The Periodic Table
- Topic: Removing the 2nd electron is always harder [ENDORSED]
- Replies: 5
- Views: 1556
Removing the 2nd electron is always harder [ENDORSED]
Hi! Today in lecture we discussed how removing the second electron from an element is always harder. Indeed, the 2nd ionization energy of an element is always higher than the first one. I just didn't really understand the reason behind this statement. Why is it harder to remove an electron from an e...
- Mon Apr 30, 2018 9:50 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Terminology with quantum numbers
- Replies: 3
- Views: 562
Re: Terminology with quantum numbers
Thank you Gianna and Kimberly! :)
- Mon Apr 30, 2018 6:15 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Terminology with quantum numbers
- Replies: 3
- Views: 562
Terminology with quantum numbers
While I was doing the homework problems, I came across some questions where I wasn't sure which quantum number they were asking me to find. So I just wanted to make sure: - when they ask for the number of orbitals, does that mean the quantum number ml? - when they ask for the number of subshells, do...
- Sun Apr 29, 2018 9:50 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: How to properly format your answers
- Replies: 6
- Views: 627
Re: How to properly format your answers
I don't think it indicates different properties of the electrons configuration. Dr. Lavelle just used half arrows, but he said it didn't matter which one you used.
- Sun Apr 29, 2018 9:43 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Indeterminacy of Momentum
- Replies: 2
- Views: 369
Re: Indeterminacy of Momentum
I agree, we don't really have a number to which we can compare the uncertainty of momentum to see if it's realistic, but it's easy to compare the uncertainty of velocity to the speed of light to see if it is realistic.
Anna De Schutter - section 1A
Anna De Schutter - section 1A
- Sun Apr 29, 2018 9:37 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: In class problem [ENDORSED]
- Replies: 6
- Views: 831
Re: In class problem [ENDORSED]
I agree that for the example we did in class, we could say it was an impossible outcome because the the speed of an electron can never be faster than the speed of light since it has a mass. Maybe to determine if the uncertainty of position is reasonable we could have compared it to the diameter of t...
- Sun Apr 29, 2018 4:36 pm
- Forum: DeBroglie Equation
- Topic: HW 1.33
- Replies: 12
- Views: 1197
Re: HW 1.33
Ek=0m/s in this question (part b) because the question is asking us to find "how much energy is required to remove the electron from the metal surface". This implies that we are looking for the threshold energy (also called the work function) in this question and the threshold energy means...
- Sat Apr 21, 2018 4:02 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]
- Replies: 2
- Views: 133
Re: Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]
Thank you! :) And yes you're right, n2>n1, I wrote it the wrong way, my bad!
- Sat Apr 21, 2018 12:44 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Quiz 2 [ENDORSED]
- Replies: 4
- Views: 388
Re: Quiz 2 [ENDORSED]
Thank you!!
- Sat Apr 21, 2018 11:37 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Quiz 2 [ENDORSED]
- Replies: 4
- Views: 388
Quiz 2 [ENDORSED]
Hi! For quiz 2 if it asks us for example to calculate the frequency of light emitted by an electron that goes from n=4 to n=2 can I use the Rydberg equation: frequency = R [(1/n1^1) - (1/n2^1)] or should I go through these calculations: delta E = E(final) - E(initial) = E2-E4= (-1/4*h*R) + (1/16*h*R...
- Sat Apr 21, 2018 11:07 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]
- Replies: 2
- Views: 133
Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]
Hi! I've been struggling a bit with understanding how the solutions manual presents 1.15. So the problem states: "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 ...
- Thu Apr 19, 2018 11:51 am
- Forum: Einstein Equation
- Topic: Homework 1.25b
- Replies: 1
- Views: 255
Re: Homework 1.25b
Hi! So when we did question 1.25 a, we found that the energy emitted with one sodium atom is 3.37*10^-19J. In this question we are asking how much energy is emitted with 5.00mg of those sodium atoms. To solve this problem, we need to find how many sodium atoms there are in 5.00mg so that we can mult...
- Wed Apr 18, 2018 10:57 pm
- Forum: Properties of Light
- Topic: Homework 1.9
- Replies: 2
- Views: 445
Re: Homework 1.9
Hi! The way I went about this problem is I looked at the wavelengths I found and then I associated each with an event. In class I believe we mentioned these sample wavelengths for each component of the spectrum of light: Radio 10cm - Microwave 1mm - IR 1 micrometer - Visible 700-400nm - UV 100nm - x...
- Wed Apr 18, 2018 10:40 pm
- Forum: DeBroglie Equation
- Topic: HW 1.33
- Replies: 12
- Views: 1197
Re: HW 1.33
Hi! The information given to us in this question is that no electron is emitted until the frequency of radiation reaches 2.50*10^16 Hz. We are trying to find the amount of energy required to remove the electron from the surface, thus the threshold energy (also known as work function) required to rem...
- Sun Apr 15, 2018 5:02 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: When to use MiVi=MfVf
- Replies: 8
- Views: 4374
Re: When to use MiVi=MfVf
I'm not too sure that there would exist a case where you would need to use both equations. However, if for example you are giving n(final) and M(final) as well as M(initial), you could use M=n/V to find V(final) and then the equation M(initial)*V(initial)=M(final)*V(final) to find V(initial). You co...
- Sun Apr 15, 2018 4:23 pm
- Forum: Limiting Reactant Calculations
- Topic: Finding Excess Amount of Reactant [ENDORSED]
- Replies: 2
- Views: 565
Re: Finding Excess Amount of Reactant [ENDORSED]
When you are trying to determine the limiting reactant of the reaction, you find the initial amount of moles for each reactant (either given to you or you convert masses to moles using the molar mass) and then you choose one reactant (let's call it reactant 1) and depending on the molar ratios (give...
- Sun Apr 15, 2018 3:50 pm
- Forum: Empirical & Molecular Formulas
- Topic: F.21
- Replies: 5
- Views: 3069
Re: F.21
I believe that if the problem had asked to find the empirical formula, we would have also found C49H78N6O12 because as said by Dr. Lavelle just above, the empirical formula and molecular formula are the same in this problem because the ratios of the molecular formula (C49H78N6O12) are irreducible. M...
- Fri Apr 06, 2018 1:21 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.5 [ENDORSED]
- Replies: 3
- Views: 553
Re: G.5 [ENDORSED]
Hi Madeleine! To come back to your question about G5 part c I think this is one way to look at it: According to the key concept: When diluting a solution, moles of solute remain the same, we can write: n(initial)=n(final) or M(initial)*V(initial)=M(final)*V(final) In part c of problem G5 we want to ...
- Fri Apr 06, 2018 12:40 pm
- Forum: Significant Figures
- Topic: Sig Figs [ENDORSED]
- Replies: 9
- Views: 930
Re: Sig Figs [ENDORSED]
Hi Brynne! From what I understood during my discussion section points will not be taken off if we don't use the correct number of significant figures; however, you shouldn't give too many numbers after the decimal point either (like 10 for example). If I remember correctly my teaching assistant told...
- Fri Apr 06, 2018 12:33 pm
- Forum: SI Units, Unit Conversions
- Topic: Using units in calculations [ENDORSED]
- Replies: 4
- Views: 305
Using units in calculations [ENDORSED]
Hi! I've noticed in the solutions manual that units are used for every value when doing calculations. For example if they want to calculate the number of moles of C knowing that the mass of C is 67.49g (problem F15) they write: (67.49g)/(12.01g/mol)=5.619mol I was just wondering would it be okay to ...