Search found 106 matches

by Paige Lee 1A
Wed Feb 12, 2020 3:03 pm
Forum: Phase Changes & Related Calculations
Topic: 4.5
Replies: 2
Views: 22

Re: 4.5

Find the amount of heat transferred to ice in 0.5hrs using q=mCdeltaT. You will get 3135J transferred in 0.5 hrs. Then use dimensional analysis to find how many joules are transferred in 10hrs. You get 62.7kJ transferred in 10hrs. Then divide 62.7kJ by 8.33 moles and get 7.53kJ/mol for enthalpy of f...
by Paige Lee 1A
Wed Feb 12, 2020 3:00 pm
Forum: Student Social/Study Group
Topic: midterm location
Replies: 1
Views: 24

Re: midterm location

It's on north campus towards the back end of the sculpture garden. It's a big white colored building.
by Paige Lee 1A
Wed Feb 12, 2020 2:58 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess Law
Replies: 6
Views: 34

Re: Hess Law

Given the main reaction, find the sum of the entropies, enthalpies, etc. of the reactants and products
by Paige Lee 1A
Wed Feb 12, 2020 12:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Textbook question 4J.17
Replies: 2
Views: 31

Textbook question 4J.17

Could someone please explain why for B and C you know that the reactions are spontaneous everywhere and nonspontaneous everywhere respectively? Why don't you calculate the maximum temperature cut off? Why are parts B and C different from part A of this question? Assume that DH8 and DS8 are independe...
by Paige Lee 1A
Tue Feb 11, 2020 11:52 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Textbook question 4J.7
Replies: 2
Views: 20

Textbook question 4J.7

Could someone please explain why the deltaH for part A is subtracts the Hf of products minus reactants? Why don't we add them together? Why is the correct answer -196.1kJ/mol and not -947.22kJ/mol? Calculate the standard reaction entropy, enthalpy, and Gibbs free energy for each of the following rea...
by Paige Lee 1A
Thu Feb 06, 2020 12:25 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Textbook question 4B.9
Replies: 4
Views: 22

Textbook question 4B.9

For parts A and D, why must w=0 in an adiabatic process?
by Paige Lee 1A
Thu Feb 06, 2020 12:13 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A.9
Replies: 1
Views: 6

Re: 4A.9

I'm not entirely sure if this answers your question, but the problem did say that no heat is lost to the surroundings
by Paige Lee 1A
Thu Feb 06, 2020 12:00 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Textbook question 4B.3
Replies: 3
Views: 15

Textbook question 4B.3

The internal energy of a system increased by 982 J when it was supplied with 492 J of energy as heat. (a) Was work done by or on the system? (b) How much work was done? For part b, I keep getting 490J, but the answer key in the back of the book says 90*10^2J? Could someone please explain how to get ...
by Paige Lee 1A
Wed Feb 05, 2020 11:48 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question 4A.13
Replies: 5
Views: 24

Textbook question 4A.13

A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solu- tion in the calorimeter (q 5 23.50 kJ), resulting in a temperature rise of 7.32 8C. In a subsequent experiment, 100.0 mL of 0.200 m HBr(aq) and 100.0 mL of 0.200 m KOH(aq) wer...
by Paige Lee 1A
Mon Feb 03, 2020 12:04 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Textbook question 4A.3
Replies: 2
Views: 43

Textbook question 4A.3

Could someone please explain why part c is 8J and not 28J? Also how do you get 8J? Air in a bicycle pump is compressed by pushing in the handle. The inner diameter of the pump is 3.0 cm and the pump is depressed 20. cm with a pressure of 2.00 atm. (a) How much work is done in the compression? (b) Is...
by Paige Lee 1A
Sun Feb 02, 2020 11:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook question 4D.23
Replies: 1
Views: 12

Textbook question 4D.23

Calculate the standard enthalpy of formation of dinitro- gen pentoxide from the following data: 2 NO(g) 1 O2(g) ¡ 2 NO2(g) ¢H° 5 2114.1 kJ 4 NO2(g) 1 O2(g) ¡ 2 N2O5(g) ¢H° 5 2110.2 kJ and from the standard enthalpy of formation of nitric oxide, NO (see Appendix 2A). Could someone please explain why ...
by Paige Lee 1A
Sat Feb 01, 2020 8:24 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook question 4C.3
Replies: 3
Views: 49

Textbook question 4C.3

Could someone please explain how to get the correct answers for this question? For part a, I keep getting 330K and for part b, I keep getting 343K 4C.3 Calculate the final temperature and the change in enthalpy when 765 J of energy is transferred as heat to 0.820 mol Kr(g) at 298 K and 1.00 atm (a) ...
by Paige Lee 1A
Sat Feb 01, 2020 8:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question 4D.9
Replies: 3
Views: 29

Re: Textbook question 4D.9

That is correct the O2 and N2 are diatomic gases in their most stable form and thus their standard enthalpy of formation is zero. Using the enthalpies of formation we calculate that CO2 requires -393.51 kJ/mol while H20 requires -241.82. Given TNT's enthalpy of formation we calculate: 28(-393.51 kJ...
by Paige Lee 1A
Sat Feb 01, 2020 8:19 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: how to solve thermodynamics problems
Replies: 2
Views: 17

Re: how to solve thermodynamics problems

Something that might help is writing down what you are given from the problem and what you are trying to solve for. This may help you decide which formula to use and which units to try to get
by Paige Lee 1A
Sat Feb 01, 2020 12:53 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question 4D.9
Replies: 3
Views: 29

Textbook question 4D.9

Could someone please explain how to get the correct answer? The enthalpy of formation of trinitrotoluene (TNT) is 267 kJ?mol21, and the density of TNT is 1.65 g?cm23. In princi- ple, it could be used as a rocket fuel, with the gases resulting from its decomposition streaming out of the rocket to giv...
by Paige Lee 1A
Sat Feb 01, 2020 12:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook question 4D.3
Replies: 1
Views: 22

Textbook question 4D.3

Could someone please explain how to get the correct answer for part b? I keep getting 2.06kJ The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113 deg...
by Paige Lee 1A
Sat Jan 25, 2020 1:50 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook question 4C.3
Replies: 2
Views: 51

Textbook question 4C.3

What are the correct answers for this question? The answer key just says the answer is 373K, but there are four parts to this question. 4C.3 Calculate the final temperature and the change in enthalpy when 765 J of energy is transferred as heat to 0.820 mol Kr(g) at 298 K and 1.00 atm (a) at constant...
by Paige Lee 1A
Thu Jan 23, 2020 7:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Value of Ka, Kw, Kb
Replies: 5
Views: 23

Re: Value of Ka, Kw, Kb

Ka and Kb are specific to a reaction at a specific temperature
by Paige Lee 1A
Thu Jan 23, 2020 7:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K value
Replies: 7
Views: 20

Re: K value

I think you should try to exclude the x value if K is slightly less than 10^-3. But still make sure to check that the percent ionization is less than 5% for a valid approximation
by Paige Lee 1A
Thu Jan 23, 2020 7:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quadratic Equation for [EQ]
Replies: 1
Views: 12

Re: Quadratic Equation for [EQ]

I like to do the quadratic equation in small, separate parts to make sure I don't mess up. The first calculations I do are the b^2 and 4ac. The second set of calculations I do is solving for what is inside the radical and then taking the square root of it. After that, I add/subtract -b to/from that ...
by Paige Lee 1A
Mon Jan 20, 2020 12:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6D.13
Replies: 2
Views: 27

Re: Textbook question 6D.13

Rank the following solutions in order of increasing pH: (a) 1.0 3 1025 m HCl(aq); (b) 0.20 m CH3NH3Cl(aq); (c) 0.20 m CH3COOH(aq); (d) 0.20 m C6H5NH2(aq). Justify your ranking.
by Paige Lee 1A
Mon Jan 20, 2020 12:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6.19
Replies: 2
Views: 25

Re: Textbook question 6.19

Hemoglobin (Hb) molecules in blood carry O2 molecules from the lungs, where the concentration of oxygen is high, to the tissues where it is low (see the Interlude following Focus 5). In the tissues the equilibrium H3O1(aq) 1 HbO22 (aq) ∆ HHb(aq) 1 H2O(l) 1 O2(aq) releases oxygen. When muscles work h...
by Paige Lee 1A
Fri Jan 17, 2020 8:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6.19
Replies: 2
Views: 25

Textbook question 6.19

Could someone please explain the reasoning behind part A in question 6.19?
by Paige Lee 1A
Fri Jan 17, 2020 3:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6D.13
Replies: 2
Views: 27

Textbook question 6D.13

Could someone please explain how to find the pH for parts a and d?
What are the correct pHs for parts a and d?
by Paige Lee 1A
Thu Jan 16, 2020 11:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 6D.5
Replies: 1
Views: 21

Textbook question 6D.5

For part d for the percent protonation, I got 1.49% instead of 2.5%
I got the correct values for the pOH and pH though
Could someone please explain how to get 2.5%?
by Paige Lee 1A
Wed Jan 15, 2020 11:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.39
Replies: 4
Views: 54

Re: 5.39

I found on the internet that the Kc value for the forward rxn is actually 5.9*10^-3. So, for the reverse rxn, the Kc value would be 1.69*10^2
Using these values, I got pretty similar values of concentrations as the solution manual
by Paige Lee 1A
Wed Jan 15, 2020 3:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook question 6B.11
Replies: 2
Views: 13

Textbook question 6B.11

Could someone please explain how to get the answers to parts a.ii and b?
I understand how to get part a.i
by Paige Lee 1A
Wed Jan 15, 2020 3:21 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook question 6B.9
Replies: 1
Views: 14

Textbook question 6B.9

Could someone please explain how to fill in the table for solutions 1 and 2?
I got that the concentrations were 1.50mol/L and 6.67*10^-15
I got that the pHs and pOHs for these two solutions were -0.18 and 14.18
by Paige Lee 1A
Mon Jan 13, 2020 10:26 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Module 2 Question 27
Replies: 1
Views: 28

Re: Module 2 Question 27

100g of C is 8.326 moles of C Set up an ICE table Initial C: 8.326/50 = 0.16652 Initial H2O: 2.5/50 = 0.05 Initial CO: 0 Initial H2: 0 Change: -x for C and H2O, +x for CO and H2 Equilibrium C: 0.16652-x Equilibrium H2O: 0.05-x Equilibrium CO and H2: both are x, which is given to be 0.04 Plug x=0.04 ...
by Paige Lee 1A
Mon Jan 13, 2020 2:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5.39
Replies: 1
Views: 26

Textbook question 5.39

For part A, I found the equilibrium concentrations when V=1L.
For part B, I found the equilibrium concentrations when V=0.5L.

For part A I got 0.01 for x instead of 0.0065
For part B I got 0.02 for x instead of 0.015

I'm not sure where I went wrong?
by Paige Lee 1A
Mon Jan 13, 2020 2:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5.35
Replies: 2
Views: 17

Textbook question 5.35

Could someone please explain how to get the correct answers for parts a and b?
by Paige Lee 1A
Mon Jan 13, 2020 1:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook question 5J.11
Replies: 3
Views: 15

Textbook question 5J.11

Could someone please explain how we know that the reaction in part B is endothermic?
by Paige Lee 1A
Mon Jan 13, 2020 1:39 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook question 5J.5
Replies: 2
Views: 11

Textbook question 5J.5

Could someone please explain why parts D and E have different answers? Why is part E not "no change" also?
by Paige Lee 1A
Sat Jan 11, 2020 12:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post assessment 2 question 30
Replies: 1
Views: 22

Post assessment 2 question 30

A mixture of 2.5 moles H2O and 100 g of C are placed in a 50 L container and allowed to come to equilibrium subject to the following reaction: C(s) + H2O (g) ⇌ CO (g) + H2 (g). The equilibrium concentration of hydrogen is found to be [H2] = 0.040 M. Calculate the equilibrium constant Kc of this reac...
by Paige Lee 1A
Sat Jan 11, 2020 10:22 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.27
Replies: 1
Views: 20

Textbook question 5I.27

Could someone please explain how to get the answer for part C?
by Paige Lee 1A
Sat Jan 11, 2020 9:13 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.15
Replies: 1
Views: 24

Textbook question 5I.15

Could someone please explain how to find the equilibrium concentration of H2S? Why isn't is 0.2mols/L also?
by Paige Lee 1A
Sat Jan 11, 2020 8:59 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.13
Replies: 2
Views: 22

Textbook question 5I.13

Could someone please explain how to get the correct answers for parts b and c?
by Paige Lee 1A
Fri Jan 10, 2020 3:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Example 5I.4
Replies: 4
Views: 23

Example 5I.4

For this example, how do you know to find the partial pressures and not the concentrations at equilibrium?
by Paige Lee 1A
Wed Jan 08, 2020 2:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.11
Replies: 1
Views: 27

Textbook question 5I.11

Could someone please explain how to get part a? I keep getting 13.9 instead of 6.9
by Paige Lee 1A
Wed Jan 08, 2020 2:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5I.3
Replies: 2
Views: 28

Textbook question 5I.3

Could someone please explain how to get the correct answer?
I keep getting 4.21*10^-6 mols/L
by Paige Lee 1A
Tue Jan 07, 2020 10:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook example 5H.1
Replies: 2
Views: 18

Textbook example 5H.1

Could someone please explain how to find the value of R in this example?
I understand how to get that T=673K, K=3.1*10^4, and Δnt= -1
by Paige Lee 1A
Mon Jan 06, 2020 10:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5G.11
Replies: 2
Views: 24

Textbook question 5G.11

Is it possible to problem 5G.11 without having read section 5G.4? Because the syllabus says to omit section 5G.4
by Paige Lee 1A
Mon Jan 06, 2020 10:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook question 5G.9
Replies: 2
Views: 21

Textbook question 5G.9

Could someone please explain the reasoning behind the correct answer for part C?
by Paige Lee 1A
Sat Dec 07, 2019 12:34 am
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 4121

Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]

For #1c on mini marshmallow, how do you know to choose NH4+ and not NO3- for the net ionic equation? Since they're both weak acids and bases
by Paige Lee 1A
Mon Dec 02, 2019 1:25 pm
Forum: Naming
Topic: 9C.3
Replies: 4
Views: 32

Re: 9C.3

a. K3[Cr(CN)6]
b. [Co(NH3)5SO4]Cl
c. [Co(NH3)4(OH2)2]Br3
d. Na[Fe(C2O4)2(OH2)2]
by Paige Lee 1A
Mon Dec 02, 2019 1:20 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H-atom energy levels
Replies: 1
Views: 32

Re: H-atom energy levels

Using En=-hR/n^2, write this expression twice, and make one nfinal and one ninitial. Then, switch to the form E=R{1/n1^2 - 1/n2^2}. To solve for n2^2, divide both sides by R, subtract 1/n1^2, multiply by -1, take square root
by Paige Lee 1A
Mon Dec 02, 2019 1:16 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D11 part c and d
Replies: 1
Views: 19

Re: 6D11 part c and d

KF has F- (conjugate base of weak acid) which forms basic solutions
KBr has Br- (anion of strong acid) which has no significant effect on pH of solutions
by Paige Lee 1A
Mon Dec 02, 2019 1:14 pm
Forum: Bronsted Acids & Bases
Topic: Lecture 12/2
Replies: 3
Views: 24

Re: Lecture 12/2

I think he said weak acids and bases do affect pH
by Paige Lee 1A
Mon Dec 02, 2019 1:12 pm
Forum: Calculating the pH of Salt Solutions
Topic: Textbook box 6E.1
Replies: 1
Views: 30

Textbook box 6E.1

Could someone please explain how you know to use pKa1, pKa2, pKa3, etc. to find the pH?
Will you always be given these values, or do you need to know how to solve for pKa values?
by Paige Lee 1A
Sat Nov 30, 2019 2:43 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Textbook question 6C.21
Replies: 1
Views: 21

Textbook question 6C.21

For part b, why is formic acid stronger than acetic acid?
by Paige Lee 1A
Sat Nov 30, 2019 1:05 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook question 6B.9
Replies: 2
Views: 45

Textbook question 6B.9

Why is the pH of acid #1 0.176? Why isn't it -0.176?
Isn't the formula for pH: -log[H3O+] ? So why isn't the pH negative after you plug in 1.50mols/L for the [H3O+]?
by Paige Lee 1A
Sat Nov 30, 2019 11:30 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Textbook question 6B.3
Replies: 1
Views: 24

Textbook question 6B.3

I understand how to get 1.6 for part A, but how do you get 1.7 for part B?
by Paige Lee 1A
Sat Nov 30, 2019 10:54 am
Forum: Amphoteric Compounds
Topic: Textbook question 6A.17
Replies: 1
Views: 26

Textbook question 6A.17

Could someone please explain why part d is amphoteric? Isn't Bi a metal, so why isn't it basic?
by Paige Lee 1A
Thu Nov 28, 2019 2:27 pm
Forum: Naming
Topic: Iron as the central metal
Replies: 2
Views: 25

Iron as the central metal

When do you write "ferrate," "ferrous," and "iron(oxidation state)" ?
by Paige Lee 1A
Thu Nov 28, 2019 2:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination number of [Co(Ox)3]3-
Replies: 2
Views: 17

Coordination number of [Co(Ox)3]3-

Could someone please explain why the coordination number of [Co(Ox)3]3- is 6?
If "ox" represents EDTA, which is hexadentate, why isn't the coordination number 18 because there are three Oxs?
by Paige Lee 1A
Thu Nov 28, 2019 2:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Denticity
Replies: 2
Views: 27

Denticity

Could someone please explain to determine the denticity of a ligand based on its Lewis structure?
by Paige Lee 1A
Thu Nov 28, 2019 2:17 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Pka vs Ka
Replies: 10
Views: 79

Re: Pka vs Ka

pKa represents various Ka values on a logarithmic scale, where pKa=-log[Ka] and p=-logbase 10
by Paige Lee 1A
Thu Nov 28, 2019 2:16 pm
Forum: Naming
Topic: Ligand Order
Replies: 5
Views: 46

Re: Ligand Order

If the overall charge is negative, put the ion in front of the [] brackets
If the overall charge is positive, put the ion after the [] brackets
by Paige Lee 1A
Sat Nov 23, 2019 10:27 pm
Forum: Bronsted Acids & Bases
Topic: Fundamentals question J.9
Replies: 1
Views: 23

Fundamentals question J.9

Do we need to know how to write net ionic equations?
by Paige Lee 1A
Sat Nov 23, 2019 3:17 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook question 9c.9
Replies: 1
Views: 24

Textbook question 9c.9

Could someone please explain why the coordination number for part d is 6?
by Paige Lee 1A
Sat Nov 23, 2019 3:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Textbook question 9c.5
Replies: 1
Views: 41

Textbook question 9c.5

Could someone please explain how to determine which ligands are polydentate? I drew out all the Lewis structures for this question, but I don't know where to go from there
by Paige Lee 1A
Sat Nov 23, 2019 2:26 pm
Forum: Naming
Topic: Textbook question 9C.1
Replies: 2
Views: 25

Textbook question 9C.1

Could someone please explain the reasoning behind the name "aquapentacyanocolbaltate(III)" for part c?
by Paige Lee 1A
Tue Nov 19, 2019 7:10 pm
Forum: General Science Questions
Topic: Test 2 Review
Replies: 8
Views: 96

Re: Test 2 Review

What do we need to know for "lone pairs and the reason for their locations"? I'm not sure what this is referring to
by Paige Lee 1A
Tue Nov 19, 2019 7:07 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Intermolecular Forces
Replies: 6
Views: 68

Re: Intermolecular Forces

The size of the molecule affects intermolecular forces. If the molecule is large, it will have more attractive intermolecular forces, which can cause it to change phase and become more condensed (liquid, solid).
by Paige Lee 1A
Tue Nov 19, 2019 7:02 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability
Replies: 9
Views: 66

Re: polarizability

The higher polarizability of a molecule, the stronger intermolecular forces/attractions there will be, so it will be harder to break bonds. Which means its melting point and boiling point will be high.
by Paige Lee 1A
Tue Nov 19, 2019 3:30 pm
Forum: Hybridization
Topic: Is hybridized orbitals all weighed equally in character?
Replies: 4
Views: 23

Re: Is hybridized orbitals all weighed equally in character?

I am almost positive that yes, they are all weighed equally in character
by Paige Lee 1A
Tue Nov 19, 2019 3:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.15
Replies: 1
Views: 19

Re: 2E.15

I think you are just supposed to memorize that the bond angles are less than 90 and less than 120
by Paige Lee 1A
Sun Nov 17, 2019 10:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook question 2.63 part b
Replies: 1
Views: 15

Textbook question 2.63 part b

Could someone please explain why the bond angle for b is 109.5 degrees? Why isn't it 180 degrees/linear?
by Paige Lee 1A
Sun Nov 17, 2019 4:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook question 2.63
Replies: 1
Views: 13

Textbook question 2.63

Could someone please explain why angle c is 120 degrees? Why isn't it 180 degrees?
by Paige Lee 1A
Fri Nov 15, 2019 12:14 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook question 2E.1
Replies: 4
Views: 36

Re: Textbook question 2E.1

I'm still confused, what about trigonal planar molecules? Don't they have 120 degree bond angles, but no lone pairs?
by Paige Lee 1A
Thu Nov 14, 2019 10:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook question 2E.1
Replies: 4
Views: 36

Textbook question 2E.1

For part A, could someone please explain why there must be lone pairs for a 120 degree bond angle?
by Paige Lee 1A
Mon Nov 11, 2019 3:50 pm
Forum: Dipole Moments
Topic: Textbook question 3F.19 part c
Replies: 1
Views: 19

Textbook question 3F.19 part c

Could someone please explain how we know the shapes of CH3(CH2)3CH3 and C(CH3)4? If we're supposed to draw the Lewis structure for each, how do we determine the shape/properties of each molecule just from its Lewis structure?
by Paige Lee 1A
Mon Nov 11, 2019 3:48 pm
Forum: Dipole Moments
Topic: Textbook question 3F.19 part b
Replies: 2
Views: 15

Textbook question 3F.19 part b

Could someone please explain the reason why the vapor pressure of C2H5OC2H5 is greater than that of H2O?
by Paige Lee 1A
Mon Nov 11, 2019 3:46 pm
Forum: Dipole Moments
Topic: Textbook question 3F.1
Replies: 5
Views: 43

Textbook question 3F.1

Could someone please explain how they found the various attractive intermolecular interactions that may arise between molecules of each substance?
I don't understand how to determine these interactions

a. NH2OH
b. CBr4
c. H2SeO4
d. SO2
by Paige Lee 1A
Tue Nov 05, 2019 7:57 pm
Forum: Lewis Structures
Topic: 7 lewis structure
Replies: 1
Views: 31

Re: 7 lewis structure

For the actual CO2 structure (the one with double bonds), the FC on O and C atoms are all 0.
For the other CO2 structure (the one with the triple bond), the FC on the O atoms are -1 and 1.
The actual CO2 structure is "more important" because it has lower energy since the FCs are all 0
by Paige Lee 1A
Tue Nov 05, 2019 7:52 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum Number Sequence
Replies: 1
Views: 21

Re: Quantum Number Sequence

It's not possible because if l=0, then ml can only be 0. Values of ml are -l through l. Since l is 0, ml can only be 0. We just need to know that each ml value corresponds to a different orbital in the subshell.
by Paige Lee 1A
Tue Nov 05, 2019 7:48 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D Subshell
Replies: 7
Views: 65

Re: D Subshell

10. There are 5 orbitals in a d subshell. A maximum of 2 electrons can go in each orbital.
by Paige Lee 1A
Tue Nov 05, 2019 7:46 pm
Forum: Photoelectric Effect
Topic: Wavelength to Frequency
Replies: 3
Views: 50

Re: Wavelength to Frequency

Hello, can anyone tell me the steps to go from a given wavelength and work function to frequency?

Convert wavelength to E (joules) using E=hc/λ
Plug E into E=hν, solve for v (frequency in Hz)
by Paige Lee 1A
Tue Nov 05, 2019 7:38 pm
Forum: Ionic & Covalent Bonds
Topic: Textbook question 2.25
Replies: 2
Views: 31

Textbook question 2.25

Which bond is longer: (a) the CN bond in HCN or in H3CNH2? (b) The NF bond in NF3 or the PF bond in PF3?

For part A, I got that the bond in H3CNH2 is longer, is this the correct answer?
For part B, I got that the NF bond in NF3 and the PF bond in PF3 were the same length--is this correct?
by Paige Lee 1A
Sun Nov 03, 2019 10:57 pm
Forum: Properties of Electrons
Topic: Molecular spectroscopy
Replies: 1
Views: 49

Molecular spectroscopy

Could someone please explain what molecular spectroscopy is? This was a bullet point on outline 2: With respect to electron transitions that give rise to a UV or visible spectrum: understand the difference between electronic transitions in atomic orbitals (atomic spectroscopy) and electronic transit...
by Paige Lee 1A
Sun Nov 03, 2019 3:08 pm
Forum: *Shrodinger Equation
Topic: H ψ = E ψ
Replies: 2
Views: 49

H ψ = E ψ

Could someone please explain what H ψ = E ψ means?
by Paige Lee 1A
Sat Nov 02, 2019 6:28 pm
Forum: Resonance Structures
Topic: Textbook question 2B.15
Replies: 1
Views: 19

Textbook question 2B.15

Why are there only two possible resonance structures for ClNO2 and not three? Why can't N be double bonded to Cl?
by Paige Lee 1A
Wed Oct 30, 2019 11:48 pm
Forum: Lewis Structures
Topic: Textbook question 2B.9
Replies: 1
Views: 28

Textbook question 2B.9

I had a lot of trouble figuring out how to draw the Lewis structures of these compounds. Would it be a good idea to memorize the structures of common ions (like NH4+, ClO-, etc.)? Also why are the ions in the compound drawn separately from each other as opposed to being connected/bonded to each other?
by Paige Lee 1A
Wed Oct 30, 2019 10:28 pm
Forum: Ionic & Covalent Bonds
Topic: Textbook question 2A.19 part e
Replies: 2
Views: 22

Textbook question 2A.19 part e

Could someone please explain why the e- configuration of Ni^2+ is [Ar]3d^8 instead of [Ar]3d^6 4s^2?
by Paige Lee 1A
Tue Oct 29, 2019 3:52 pm
Forum: Ionic & Covalent Bonds
Topic: Textbook question 2A.1
Replies: 2
Views: 22

Textbook question 2A.1

Could someone please explain why the answer to part a is that Sb has 5 valence electrons? I'm confused about why the 5s^2 isn't included in the number of valence electrons, but the 5p^5 is.
by Paige Lee 1A
Sat Oct 26, 2019 9:57 pm
Forum: Properties of Electrons
Topic: Textbook question 1.31
Replies: 1
Views: 36

Textbook question 1.31

In a recent suspense film, two secret agents must penetrate a criminal's stronghold monitored by a lithium photomultiplier cell that is continually bathed in light from a laser. If the beam of light is broken, an alarm sounds. The agents want to use a hand- held laser to illuminate the cell while th...
by Paige Lee 1A
Thu Oct 24, 2019 4:00 pm
Forum: Trends in The Periodic Table
Topic: Calculated vs Observed Value
Replies: 6
Views: 38

Re: Calculated vs Observed Value

I think he means that the calculations you do based on the periodic table may differ from observed results in an actual experiment in real life
by Paige Lee 1A
Thu Oct 24, 2019 3:41 pm
Forum: Trends in The Periodic Table
Topic: Location of elements
Replies: 12
Views: 114

Re: Location of elements

Does anyone know if we should know the elements' chemical symbols too?
by Paige Lee 1A
Thu Oct 24, 2019 9:43 am
Forum: Trends in The Periodic Table
Topic: Summary of Periodic Trends
Replies: 7
Views: 79

Re: Summary of Periodic Trends

Could someone please explain why noble gases have a negative electron affinity?
by Paige Lee 1A
Thu Oct 24, 2019 9:40 am
Forum: Properties of Electrons
Topic: Electron transition question
Replies: 2
Views: 40

Electron transition question

In the hydrogen atomic spectrum, what is the wavelength of light associated with the n=4 to n=1 electron transition? What part of the EM spectrum is this wavelength?

I keep getting -9.73*10^-8m, could someone please explain how to get the correct answer?
by Paige Lee 1A
Thu Oct 24, 2019 9:35 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question about speed uncertainty
Replies: 1
Views: 21

Question about speed uncertainty

Assume a car’s position uncertainty is ±5m when its speed is measured and its mass is 2,150kg. What is its speed uncertainty? I got the correct answer, which is Δv = 2.45•10-39m/s. But the 2nd part of the question asks: Why is this calculation not very helpful? I don't understand why this calculatio...
by Paige Lee 1A
Thu Oct 17, 2019 9:58 pm
Forum: DeBroglie Equation
Topic: 25.
Replies: 4
Views: 46

Re: 25.

Do Δp*Δx ≥ h/4pi, and then plug in the Δp value into this equation: Δp=mΔv and solve for Δv
by Paige Lee 1A
Thu Oct 17, 2019 9:55 pm
Forum: DeBroglie Equation
Topic: 1B.15c
Replies: 2
Views: 21

Re: 1B.15c

Use the frequency (2.50*10^16Hz) that they give you. Then plug that into E=hv and get 1.66*10^-17J
by Paige Lee 1A
Thu Oct 17, 2019 4:17 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook question 1b.21
Replies: 2
Views: 35

Textbook question 1b.21

I got the correct answer for this question (1.11*10^-34), but can someone please explain why we were given the information that the baseball "must weigh between 5.00 and 5.25oz?" I didn't end up using this information when doing the problem. I only used the 5.15oz, which was given too, and...
by Paige Lee 1A
Mon Oct 14, 2019 4:40 pm
Forum: Properties of Electrons
Topic: Question from Heisenberg's Uncertainty Principle post test
Replies: 2
Views: 58

Question from Heisenberg's Uncertainty Principle post test

The hydrogen atom's radius is approximately 0.05nm. Assume that we know the position of the electron to an accuracy of 1% of the hydrogen radius. Calculate the uncertainty in speed of the electron using the Heisenberg uncertainty principle. What is the correct answer for this question, and what is t...
by Paige Lee 1A
Mon Oct 14, 2019 4:35 pm
Forum: Properties of Electrons
Topic: Question about diffraction patterns
Replies: 3
Views: 35

Question about diffraction patterns

When classical particles hit a barrier with two or more holes, do the particles that pass through the holes give rise to an observed diffraction pattern?
Why is the correct answer "no" ?
by Paige Lee 1A
Sat Oct 12, 2019 6:06 pm
Forum: Properties of Light
Topic: Atomic spectra post test
Replies: 1
Views: 58

Atomic spectra post test

Could someone please explain how to get the correct answers for these three questions? 28. The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radiation? To what region of the electromag...
by Paige Lee 1A
Fri Oct 11, 2019 4:59 pm
Forum: Photoelectric Effect
Topic: Post Module Assessment
Replies: 1
Views: 30

Re: Post Module Assessment

Since a joule is an SI derived unit, 1 joule is really kg.m^2.s^−2. For the equation, the m part is in kg, and the velocity squared part is in m.s^-1 squared.
by Paige Lee 1A
Fri Oct 11, 2019 4:55 pm
Forum: Properties of Light
Topic: Photoelectric effect- post assessment question #34
Replies: 1
Views: 20

Photoelectric effect- post assessment question #34

Molybdenum metal must absorb radiation with a minimum frequency of 1.09 x 10^15 s-1 before it can emit an electron from its surface. If molybdenum is irradiated with 194 nm light, what is the maximum possible kinetic energy of the emitted electrons? I got #33 correct (7.22 x 10^-19 J is the minimum ...
by Paige Lee 1A
Fri Oct 11, 2019 4:52 pm
Forum: Properties of Light
Topic: Photoelectric effect- post assessment questions #29 and 30
Replies: 2
Views: 20

Photoelectric effect- post assessment questions #29 and 30

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. 29. How much energy is required to remove an electron from one sodium atom? 30. What is the frequency of the incident light on the sodium metal surface? For...

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