Search found 72 matches

by Ricky Ma DIS 4E
Fri Mar 15, 2019 12:01 pm
Forum: First Order Reactions
Topic: Half life
Replies: 4
Views: 71

Re: Half life

What are the different kinds of answers that the half life equation can give us?
by Ricky Ma DIS 4E
Fri Mar 15, 2019 11:53 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Rules for delta U
Replies: 2
Views: 200

Re: Rules for delta U

delta U equals 0 when the system doesn't change. Either when q and w=0 or q=-w
by Ricky Ma DIS 4E
Thu Mar 14, 2019 5:38 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre Equilibrium Approach
Replies: 3
Views: 238

Pre Equilibrium Approach

When would one use the pre-equilibtium approach. What would the question be asking? I can't seem to find a problem where it explicitly asks for one to use the approach to solve for something?
by Ricky Ma DIS 4E
Fri Mar 08, 2019 9:50 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Mechanism
Replies: 2
Views: 57

Re: Reaction Mechanism

All the intermediate steps between the beginning and final equation that is given to you. All the steps that happen that results in the equation that is given to you.
by Ricky Ma DIS 4E
Fri Mar 08, 2019 9:46 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2: Melting Ice
Replies: 6
Views: 253

Re: Test 2: Melting Ice

Ice melts by itself which requires no direct input of energy. A piece of ice outside would melt by itself thus spontaneous.
by Ricky Ma DIS 4E
Fri Mar 08, 2019 9:43 pm
Forum: General Rate Laws
Topic: coefficient question
Replies: 2
Views: 63

Re: coefficient question

Don't you just write the coefficient under 1? For example 1/a(d(x)/d(t)?
by Ricky Ma DIS 4E
Sun Mar 03, 2019 3:18 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: The Nernst equation
Replies: 2
Views: 71

Re: The Nernst equation

If all your other values have kelvin within them, use kelvin. Check whether or not the units cancel. From my knowledge, Im pretty sure Kelvin is always used.
by Ricky Ma DIS 4E
Sun Mar 03, 2019 3:17 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Corrosion and Ion Selective Electrodes
Replies: 4
Views: 94

Re: Corrosion and Ion Selective Electrodes

If you don't quite grasp the concept, I would suggest reading the book. Other than that I think you should be fine.
by Ricky Ma DIS 4E
Sun Mar 03, 2019 3:16 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 1
Views: 44

Re: Nernst Equation

Ecell is not under standard conditions whether Ecell^o is under standard conditions. It will usually tell you it is under 1 atm of pressure or 25 degrees celsius etc.
by Ricky Ma DIS 4E
Sat Feb 23, 2019 8:40 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs Free Energy and Pressure and K
Replies: 2
Views: 49

Re: Gibbs Free Energy and Pressure and K

I think pressure is correlated to volume which a change in volume affects the concentrations. I dont think we went over it yet but it is going to be related to the Nerdst equation.
by Ricky Ma DIS 4E
Sat Feb 23, 2019 8:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cell Diagram
Replies: 3
Views: 71

Re: Galvanic Cell Diagram

"Know how to write and interpret cell diagrams." is on his course outline. In my opinion, wouldn't hurt to know.
by Ricky Ma DIS 4E
Sat Feb 23, 2019 8:36 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: What is residual entropy?
Replies: 3
Views: 345

Re: What is residual entropy?

Residual entropy is the entropy that remains after molecules stop moving at 0 degrees kelvin. The entropy lies within the orientation of the atoms of the molecule.
by Ricky Ma DIS 4E
Sun Feb 17, 2019 12:17 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Signs
Replies: 4
Views: 86

Re: Gibbs Free Energy Signs

a negative gibbs free energy means that it is spontaneous. A postive gibbs free energy means that it is not spontaneous.
by Ricky Ma DIS 4E
Sun Feb 17, 2019 12:15 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: First Law
Replies: 3
Views: 78

Re: First Law

Delta n is used when you are given a reaction and you see that there is a change of moles within the equation. When there is a change in moles of a gas, there is work of expansion.
by Ricky Ma DIS 4E
Mon Feb 11, 2019 10:02 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: 4G. 2B 7th edition
Replies: 2
Views: 57

Re: 4G. 2B 7th edition

I think it is because ice is a solid and the molecules within are very tightly compacted meaning there is very minimal movement within the ice. Entropy would be very close to 0.
by Ricky Ma DIS 4E
Mon Feb 11, 2019 10:00 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: le chatelier's principle and continuing rxns
Replies: 2
Views: 84

Re: le chatelier's principle and continuing rxns

Yes, if you do not have enough reactants to form the products loss, the reaction will stop.
by Ricky Ma DIS 4E
Thu Feb 07, 2019 1:58 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 4
Views: 76

Re: Work

Doesnt negative work mean that the system is losing energy from work? if p=1 atm but there is an increase in volume, the equation would be negative meaning system did work of expansion.
by Ricky Ma DIS 4E
Thu Feb 07, 2019 12:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work
Replies: 4
Views: 76

Work

When the work of a system on the atmosphere is positive, does that mean that work is being done on it instead? What does positive work mean conceptually.
by Ricky Ma DIS 4E
Tue Feb 05, 2019 4:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: heat capacity
Replies: 2
Views: 60

heat capacity

it heat capacity and enthalpy of vaporization/sublimation the same thing?? Are they closely related conceptually?
by Ricky Ma DIS 4E
Tue Feb 05, 2019 12:18 am
Forum: Calculating Work of Expansion
Topic: q and delta H
Replies: 3
Views: 78

Re: q and delta H

q is heat whereas delta H is the total energy in the system at a constant pressure.
by Ricky Ma DIS 4E
Thu Jan 31, 2019 7:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4E.5 part a
Replies: 1
Views: 42

4E.5 part a

when i drew the molecular formula for benzene, there are 3 double and single bonds, therefore, I used those mean bond enthalpies. Within the solution manual, it used the other dotted doubly bond enthalpy. Why is this? Is this because benzene has resonance structures?
by Ricky Ma DIS 4E
Tue Jan 29, 2019 11:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Method #3
Replies: 2
Views: 73

Re: Method #3

I think method 3 just gives you the deltaH of formation for the reactions and the deltaH of formation for the products in which you just do deltaH of the products minus the delta H of the reactants. That will give you the overall enthalpy change. It is probably the most straight forward one out of t...
by Ricky Ma DIS 4E
Tue Jan 29, 2019 11:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework
Replies: 9
Views: 157

Re: Homework

It is pretty all over the place right now. I skipped around the sections to find some problems that pertained to what we learned in class. There are not a lot.
by Ricky Ma DIS 4E
Thu Jan 24, 2019 5:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Composition
Replies: 2
Views: 53

Re: Equilibrium Composition

Percent ionization is ionized concentration/original concentration. That is a step further than just finding equilibrium composition.
by Ricky Ma DIS 4E
Thu Jan 24, 2019 5:00 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Le Chateliers Priniciple
Replies: 9
Views: 261

Re: Le Chateliers Priniciple

Technically it will but in reality, it is the volume that is increasing/decreasing that makes the reaction shift.
by Ricky Ma DIS 4E
Tue Jan 22, 2019 10:48 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Acids and bases
Replies: 2
Views: 93

Re: Acids and bases

You use the pH to find the pOH in which you can then use to find the concentration of OH-. From that you just set the quadratic equation and solve Kb from there.
by Ricky Ma DIS 4E
Thu Jan 17, 2019 12:33 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.9
Replies: 2
Views: 82

6B.9

(i), when i divide 1.0x10^-14/1.50 to get concentration of OH-, i get 6.667x10^-15 but the solution manual says the answer is 1.5x10^14. I tried to work backwards from the other values given in the table and it seems that the issue is the 1.50 molar concentration given in the table. Am I not seeing ...
by Ricky Ma DIS 4E
Wed Jan 16, 2019 11:46 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6A.23
Replies: 2
Views: 62

6A.23

When calculating the molarity for barium hydroxide, i got 2.5x10^-3 but the back of the book states that it is 2.5x10^-2, is this an error of the book?
by Ricky Ma DIS 4E
Wed Jan 16, 2019 7:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Percentage Ionization
Replies: 4
Views: 123

Re: Percentage Ionization

Yes, I believe so
by Ricky Ma DIS 4E
Wed Jan 16, 2019 7:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acid or Base
Replies: 1
Views: 43

Re: Acid or Base

Some compounds can either act as a base or an acid, those compounds are labeled as amphoteric. The best way would be to draw the lewis structure and see if it can actually give off a proton or if the Nitrogen has a lone pair. In some cases, although it is amphoteric, acting as a base/acid is more fa...
by Ricky Ma DIS 4E
Sun Jan 13, 2019 7:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 7th Edition 5I.13
Replies: 1
Views: 54

7th Edition 5I.13

Can someone show me what the set up for the quadratic equation for A is? I keep on getting 2X^2+1.2x10^-7X-1.2x10^-10 as my equation which when i plug it in into the quadratic formula, it gives me 8,69x10^-5 which gives me the wrong answer. Thanks!
by Ricky Ma DIS 4E
Thu Jan 10, 2019 12:26 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 7th edition 5H.1
Replies: 1
Views: 18

7th edition 5H.1

N2+3H2---->2NH3 at 400k K=41

1/2N2+3/2H2---->NH3 at 400k K=41



Can someone explain to me how one would figure out K of the second equation by using the information in the first line? Thanks!
by Ricky Ma DIS 4E
Thu Jan 10, 2019 12:24 am
Forum: Ideal Gases
Topic: Algebra
Replies: 5
Views: 80

Algebra

Can someone explain to me how P=(Conc)RT becomes Conc=P/RT? And for clarification P stand for partial pressure right?
by Ricky Ma DIS 4E
Tue Jan 08, 2019 7:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G3
Replies: 2
Views: 72

5G3

Does it matter if we put Kp=[C2H4Cl2]^2 ect. instead of K=[PC2H4Cl2]^2? Thanks!
by Ricky Ma DIS 4E
Fri Dec 07, 2018 11:58 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 3
Views: 221

Re: Cisplatin

Cis- means on the cisplatinum means that Chlorine atoms on the platinum are on the same side. This allows the cisplatinum to bind to the guanines at two parts on the DNA structure. The Nitrogens on the guanene bases replaces the Cl- on the cis platinum. This process results in the inhibition of the ...
by Ricky Ma DIS 4E
Fri Dec 07, 2018 11:45 pm
Forum: Bronsted Acids & Bases
Topic: Bases
Replies: 4
Views: 122

Re: Bases

Grp 1 and grp 2 oxides are the strong bases.
by Ricky Ma DIS 4E
Sun Dec 02, 2018 4:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 91

Re: Polydentate

Do I have to draw the lewis structures? How do I know if it is tri-bi-or mono dentate?
by Ricky Ma DIS 4E
Sun Dec 02, 2018 4:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 91

Polydentate

What does polydentate mean and how do I know which ligands can be polydentate?
by Ricky Ma DIS 4E
Sun Dec 02, 2018 3:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation number
Replies: 3
Views: 104

Oxidation number

How do I find the oxidation number of a complex?
by Ricky Ma DIS 4E
Sun Dec 02, 2018 2:58 pm
Forum: Naming
Topic: Coordination Sphere
Replies: 2
Views: 45

Re: Coordination Sphere

Coordination sphere is just the name given to all of the compounds and molecules within the brackets.
by Ricky Ma DIS 4E
Tue Nov 27, 2018 7:54 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: London dispersion
Replies: 1
Views: 51

Re: London dispersion

it is just saying how strong the london forces are. Larger polarazability means stronger london forces.
by Ricky Ma DIS 4E
Tue Nov 27, 2018 7:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Non-polar
Replies: 6
Views: 136

Re: Polar vs. Non-polar

Just think about the net dipoles and whether they cancel. You have to take in account the shape of the molecule.
by Ricky Ma DIS 4E
Tue Nov 27, 2018 7:50 pm
Forum: Hybridization
Topic: Empty p orbitals
Replies: 3
Views: 270

Re: Empty p orbitals

The unhybridized p orbital is the pi bond of the double bond.
by Ricky Ma DIS 4E
Sat Nov 17, 2018 5:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.29
Replies: 2
Views: 52

2E.29

For these problems, should we be able to derive the answer by just looking at it or do we have to draw out all the different lewis structures?








?
by Ricky Ma DIS 4E
Thu Nov 15, 2018 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal
Replies: 10
Views: 125

Re: Trigonal Pyramidal

ok thanks!
by Ricky Ma DIS 4E
Thu Nov 15, 2018 9:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal
Replies: 10
Views: 125

Re: Trigonal Pyramidal

A trigonal planer has bond angles of 120 degrees though. 109.5 degrees is for tetrahedral species. so wouldnt the bond angles be slightly less than 120 degrees instead of 109.5?
by Ricky Ma DIS 4E
Thu Nov 15, 2018 9:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal
Replies: 10
Views: 125

Re: Trigonal Pyramidal

And in that case wouldn't it be slightly less than 120 degrees since trigonal planar is 120 degrees? SO3^2- is just 3 bonding regions with one lone pair.
by Ricky Ma DIS 4E
Thu Nov 15, 2018 9:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal
Replies: 10
Views: 125

Re: Trigonal Pyramidal

Wouldnt this make it not even close to a tetrahedral? why does it say in my notes that it has tetrahedral arrangement?
by Ricky Ma DIS 4E
Thu Nov 15, 2018 9:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal
Replies: 10
Views: 125

Trigonal Pyramidal

Within my notes from lecture, it says it has 4 areas of electron density but i only see 3 for S03^2-. Is the double bond counting as two regions of electron density? Is that also why the arrangement is considered tetrahedral since of the double bond despite only having 3 oxygen molecules surrounding...
by Ricky Ma DIS 4E
Thu Nov 15, 2018 8:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Vespr Formula
Replies: 6
Views: 108

Vespr Formula

Within the homework there are questions that go over Vespr formula but we didnt go over that. Would we need to know those for tests/quizzes?
by Ricky Ma DIS 4E
Sun Nov 11, 2018 8:38 pm
Forum: Bond Lengths & Energies
Topic: bond energy
Replies: 4
Views: 94

Re: bond energy

Bond energy usually has to be searched up. I think doctor lavelle searched up the bond lengths in class.
by Ricky Ma DIS 4E
Sun Nov 11, 2018 8:20 pm
Forum: Dipole Moments
Topic: Fluctuation
Replies: 3
Views: 134

Re: Fluctuation

It is just that electrons are moving around an atom at all times. Luckily and by chance, they would be at one side of the atom which can cause induced dipole movements.
by Ricky Ma DIS 4E
Sun Nov 11, 2018 8:17 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent vs Ionic Characteristics
Replies: 2
Views: 96

Re: Covalent vs Ionic Characteristics

The covalent characteristics are the Cl- having higher electronegativity so it pulls the electrons from the Na closer to itself. Although NaCl is an ionic bond, no bond is 100% ionic or covalent. The electronegativity of atoms gives atoms it's covalent characteristics.
by Ricky Ma DIS 4E
Sat Nov 03, 2018 9:35 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Exam 2 Question 1A
Replies: 2
Views: 150

Re: Exam 2 Question 1A

Wasn't it a carbon monoxide molecude? not an oxygen?
by Ricky Ma DIS 4E
Sat Nov 03, 2018 9:34 pm
Forum: Octet Exceptions
Topic: Radicals - On Which Element Does the Unpaired Electron Go?
Replies: 2
Views: 120

Re: Radicals - On Which Element Does the Unpaired Electron Go?

The radical goes on the element where it will make the formal charge be 0 or closest to what your ion's charge is.
by Ricky Ma DIS 4E
Sat Nov 03, 2018 9:32 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Exceptions
Replies: 2
Views: 62

Re: Formal Charge Exceptions

Sometimes not every formal charge all add up to 0. In cases where it is an ion, the formal charges have to add up to the charge of the given ion.

ex. Sc2+
the overall formal charge will always be 2+, never 0.
by Ricky Ma DIS 4E
Sun Oct 28, 2018 11:16 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 3
Views: 95

Re: Orbitals

ms is the spin of the electron. There is no way to knowing, you can characterize it with either a +1/2 spin or -1/2 spin. It will always be those two. It doesn't matter just make sure that in an orbital, there is a maximum of two electrons, each with opposide spin.
by Ricky Ma DIS 4E
Sun Oct 28, 2018 11:14 pm
Forum: Properties of Light
Topic: Standard Units
Replies: 8
Views: 216

Re: Standard Units

The standards units for lambda is meters per second or m/s
by Ricky Ma DIS 4E
Mon Oct 22, 2018 10:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.13 7th Edition
Replies: 3
Views: 62

Re: 1E.13 7th Edition

Is this another exception???? Also, further in Tungsten is in the f orbital but I thought we aren't going to write electron configurations for those? We also didn't learn that as well right? I just googled it and apparently after Xenon, that is the F block?? Im just confused as to what I need to kno...
by Ricky Ma DIS 4E
Mon Oct 22, 2018 10:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.13 7th Edition
Replies: 3
Views: 62

1E.13 7th Edition

Write the ground-state electron configuration for each of the following atoms: (a): silver,
At the back of the book it said the answer is [Kr]4D10 5s1, why is this? why isnt it 4D9 5s2, how do we know when to subtract an electron from the 5s and give it to the D orbital? thanks.
by Ricky Ma DIS 4E
Sat Oct 20, 2018 6:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1E.5 7th Edition
Replies: 2
Views: 48

1E.5 7th Edition

b) Electrons in an s orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbial can penetrate to the nucleus of the atom. (true or false) The answer to this is True which confused me because I thought the reason why...
by Ricky Ma DIS 4E
Sat Oct 20, 2018 6:07 pm
Forum: Quantum Numbers and The H-Atom
Topic: Electrons and their transitional abilities
Replies: 1
Views: 58

Electrons and their transitional abilities

When an electron goes from 1s to a 2p, this is a result of them being excited right? by like light or something. Does this mean that the electron changes shapes as they are being excited by a light or something?
by Ricky Ma DIS 4E
Sat Oct 20, 2018 4:42 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Topics We Need to Know for the Test [ENDORSED]
Replies: 5
Views: 172

Re: Topics We Need to Know for the Test [ENDORSED]

Yes, I think that the last thing we need to know for the test is orbitals and quantum numbers.
by Ricky Ma DIS 4E
Mon Oct 15, 2018 7:26 pm
Forum: DeBroglie Equation
Topic: 1B.15
Replies: 1
Views: 70

1B.15

The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 x10^3km/s (a) What is the wavelength of the ejected electron? I understand now that you use the Debroglie equation. My problem is that I tried using the Ek=0.5mv^2 first then using lambda=hc/E to find the waveleng...
by Ricky Ma DIS 4E
Sun Oct 14, 2018 12:56 am
Forum: Properties of Light
Topic: Moles in photoelectric effect? [ENDORSED]
Replies: 2
Views: 50

Moles in photoelectric effect? [ENDORSED]

Can someone explain to me why there are moles associated with Joules or the photoelectric effect in general? How are moles related to frequency etc? The mole questions really throw me off.
by Ricky Ma DIS 4E
Sun Oct 14, 2018 12:43 am
Forum: Properties of Electrons
Topic: photoelectric effect question
Replies: 2
Views: 52

Re: photoelectric effect question

0.5 is just a parameter that is used in the equation. The M stands for mass of an electron which is a constant:9.10938356 × 10-31 kg. The V is this equation does not stand for wavelength but instead velocity. V^2 means velocity squared. Within the question, they should give you the velocity of the e...
by Ricky Ma DIS 4E
Thu Oct 11, 2018 8:47 pm
Forum: Photoelectric Effect
Topic: How do I find the mass of an ejected electron?
Replies: 3
Views: 87

How do I find the mass of an ejected electron?

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.
Ek=0.5m.v^2
How do I find the mass of an ejected electron? Is it just the molar mass of sodium?
by Ricky Ma DIS 4E
Fri Oct 05, 2018 10:33 pm
Forum: Limiting Reactant Calculations
Topic: L7
Replies: 2
Views: 67

L7

(b) What mass of oxygen is needed to oxidize this amount of tristearin?

I understand part A but the different wording in part B throws me off. What does it mean what mass of O2 is needed to oxidize this amount? Are my steps still the same as normal stoichiometry? THANKS!
by Ricky Ma DIS 4E
Fri Oct 05, 2018 10:20 pm
Forum: Balancing Chemical Reactions
Topic: H19
Replies: 3
Views: 150

H19

Aspartame (C14H18N2O5) is a solid used as an artificial sweetener. Its combustion produces carbon dioxide gas, liquid water, and nitrogen gas. I thought that combustion only releases Co2 and H20, why is there another product N? Isn't the standard rule for combustion you add oxygen and the products a...
by Ricky Ma DIS 4E
Fri Oct 05, 2018 10:09 pm
Forum: Molarity, Solutions, Dilutions
Topic: G13
Replies: 1
Views: 78

G13

To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20M NH4NO3 by adding 3.0L of water. The florist then adds 100.ml of the diluted solution to an intravenous bag. How many moles of nitrogen atom will each plant receive? Solve this exercise without using a calculator. I am just overall co...

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