Search found 30 matches

by Arta Kasaeian 2C
Sun Mar 17, 2019 8:59 pm
Forum: Balancing Redox Reactions
Topic: Triprotic
Replies: 7
Views: 831

Re: Triprotic

It’s phosphoric acid and I can’t believe I got it right holy wow
by Arta Kasaeian 2C
Mon Mar 11, 2019 11:45 am
Forum: Ideal Gases
Topic: Ideal gases
Replies: 5
Views: 86

Re: Ideal gases

For our level, I think we’ll just assume it unless stated otherwise (which I hope doesn’t happen) i think they mention “assume ideal behavior”
by Arta Kasaeian 2C
Mon Mar 11, 2019 11:43 am
Forum: Zero Order Reactions
Topic: Graphs
Replies: 6
Views: 239

Re: Graphs

It’s good to know, just because some questions can be quirky like that. They’re pretty easy to learn since only one of them differs and all you need to know is the value on the y-axis of each order reaction.
by Arta Kasaeian 2C
Mon Mar 11, 2019 11:42 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: molecularity
Replies: 8
Views: 123

Re: molecularity

The molecularity states how many reactants are present in the elementary step of the reaction. So if there is : A+B or 2A, it is bimolecular
by Arta Kasaeian 2C
Mon Mar 11, 2019 11:38 am
Forum: Biological Examples
Topic: Enzymes, Lecture example.
Replies: 3
Views: 214

Re: Enzymes, Lecture example.

Since in an enzyme catalyzed reaction the rate of reaction of the enzyme doesn’t change based on the amount of reactant, and the enzyme itself is not affected, it wouldn’t be taken into account in the rate law, so it would be zero order
by Arta Kasaeian 2C
Mon Mar 11, 2019 11:25 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constanst
Replies: 3
Views: 71

Re: Equilibrium Constanst

As far as I know K for equilibrium doesn’t have units but K for rate constant does based on the order of the reaction.
by Arta Kasaeian 2C
Wed Feb 27, 2019 4:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Order in Cell Diagrams
Replies: 3
Views: 93

Re: Order in Cell Diagrams

Both work as long as they're in the same state, and either one of them in aqueous form is placed next to the salt bridge.
by Arta Kasaeian 2C
Wed Feb 27, 2019 4:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: moles of electrons of reaction
Replies: 3
Views: 59

Re: moles of electrons of reaction

n is the number of electrons transferred, to find it you would find the two half reactions, and balance them out for an equal #e. for example if cathode reaction has 2e transfer and anode reaction has 3e transfer, you would balance them for both of them to have a 6e transfer, in which case your n wo...
by Arta Kasaeian 2C
Wed Feb 27, 2019 4:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Comma versus line
Replies: 1
Views: 39

Re: Comma versus line

You use a comma between reactants/ products that are the same state. For example, Fe^3+ (aq)and Fe^2+ (aq) would be separated by a comma. However when the two substances in the equation are in different states, such as Cu (s) and Cu^2+(aq) are separated by one straight line.
by Arta Kasaeian 2C
Wed Feb 27, 2019 4:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt (s) [ENDORSED]
Replies: 8
Views: 158

Re: Pt (s) [ENDORSED]

We add Pt(s) to any side of the diagram (anode or cathode) that doesn't include a solid conductor within the reaction.
by Arta Kasaeian 2C
Wed Feb 27, 2019 3:46 pm
Forum: Balancing Redox Reactions
Topic: Oxidized vs oxidizing agent
Replies: 6
Views: 108

Re: Oxidized vs oxidizing agent

Basically the reactant in the reduction reaction is the oxidizing agent, which is what enables the reactant in the oxidized reaction to get oxidized. On the other hand, the reactant in the oxidation half reaction is the reducing agent for the reactant in the reduction half reaction.
by Arta Kasaeian 2C
Wed Feb 27, 2019 3:39 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n
Replies: 8
Views: 143

Re: n

n is the number of electrons transferred, to find it you would find the two half reactions, and balance them out for an equal #e. for example if cathode reaction has 2e transfer and anode reaction has 3e transfer, you would balance them for both of them to have a 6e transfer, in which case your n wo...
by Arta Kasaeian 2C
Wed Feb 27, 2019 3:27 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: flipping the sign of Ecell
Replies: 5
Views: 110

Re: flipping the sign of Ecell

Yes, if needed to change calculate oxidation potential, you must switch the sign of the reduction potential.
by Arta Kasaeian 2C
Wed Feb 27, 2019 3:23 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E^o(cell) vs. Ecell
Replies: 6
Views: 113

Re: E^o(cell) vs. Ecell

E^o Cell is the cell potential at standard state, which doesn't change based on concentration (or any other reason, only having its sign switched if the reaction is reverse) while E cell is not at standard conditions and changes.
by Arta Kasaeian 2C
Wed Feb 27, 2019 3:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 4
Views: 71

Re: Cell Diagrams

Usually it's preferred that the aqueous ions need to be next to the salt bridge. and there's separation with one line between the aqueous objects and the solid ones, which are put on the outside of the diagram. If the cathode/anode reaction doesn't include a solid, we put solids such as Pt(s) to fac...
by Arta Kasaeian 2C
Sun Feb 10, 2019 10:15 pm
Forum: Phase Changes & Related Calculations
Topic: Celsius and Kelvin
Replies: 6
Views: 109

Re: Celsius and Kelvin

Almost always it's preferred to use Kelvins to do the problem (and then convert the final result to celsius if the question specifically asks for it). The only instances where celsius is fine is when CHANGE in temperature is used in which there is no difference between the two.
by Arta Kasaeian 2C
Sun Feb 10, 2019 10:13 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Entropy and Enthalpy
Replies: 3
Views: 73

Re: Entropy and Enthalpy

Entropy is essentially the measure of change of enthalpy over temperature so I'd assume you can tell through that.
by Arta Kasaeian 2C
Sun Feb 10, 2019 9:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Midterm 2019
Replies: 9
Views: 197

Re: Midterm 2019

The midterm covers until entropy but doesn't include gibbs free energy.
by Arta Kasaeian 2C
Sun Feb 03, 2019 2:20 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Biological Systems
Replies: 3
Views: 85

Re: Biological Systems

Almost all biological reactions take place in aqueous solutions, not gaseous state, therefor a change in volume is not possible. Delta H = Delta U + P (Delta V), as Delta V = 0 -> Delta H = Delta U
by Arta Kasaeian 2C
Sun Feb 03, 2019 2:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: kJ vs J
Replies: 9
Views: 153

Re: kJ vs J

I don't think it matters unless specifically requested in the problem. However it's important to take account of the constants given and needed to use as the R value may specifically require the use of J over kJ.
by Arta Kasaeian 2C
Sun Feb 03, 2019 2:13 pm
Forum: Phase Changes & Related Calculations
Topic: Steam resulting in burns?
Replies: 6
Views: 106

Re: Steam resulting in burns?

His reasoning was that although both burns are caused by our bodies absorbing the heat of the substance until reaching our body temperature, the heat transferred by boiling water on accounts for the temperature change from 100 degrees celsius to whatever final temperature, while the heat change in a...
by Arta Kasaeian 2C
Sun Jan 27, 2019 10:40 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Ph and Pka
Replies: 5
Views: 74

Re: Ph and Pka

If you get pH, you can easily get the concentration of H3O+, and then using the Ice Table you can calculate all the other values going into the pKa equation and calculate the value of pKa itself.
by Arta Kasaeian 2C
Sun Jan 27, 2019 10:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE Box Ratios
Replies: 8
Views: 277

Re: ICE Box Ratios

So the “x” usually comes to work when calculating the change the concentrations/pressures we don’t know the amounts of. The (-x) is applied to the reactants side, which means when you make the table i would draw a huge line between reactants and products and anything left of that line is negative.
by Arta Kasaeian 2C
Sun Jan 27, 2019 10:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy vs Enthalpy of Formation
Replies: 2
Views: 49

Re: Bond Enthalpy vs Enthalpy of Formation

So essentially with Bond Enthalpy the concept is the change between the two values so it’s final (products) - initial (reactants). However with Enthalpy of formation we calculate the sum of the values of both sides, however when bonds are formed (in the product) the value is turned to negative. Ther...
by Arta Kasaeian 2C
Tue Jan 22, 2019 1:57 am
Forum: Phase Changes & Related Calculations
Topic: Endothermic or Exothermic
Replies: 20
Views: 560

Re: Endothermic or Exothermic

Condensation is the transformation of gas to liquid, for which energy is released, making it exothermic and within an equilibrium, an increase in temperature would favor the reactant side.
by Arta Kasaeian 2C
Tue Jan 22, 2019 1:53 am
Forum: Ideal Gases
Topic: ICE Table Values
Replies: 9
Views: 306

Re: ICE Table Values

To avoid mistakes I would convert from moles to concentration or pressure because your calculations may get messed up, even though I think the ICE table is mostly for personal purposes.
by Arta Kasaeian 2C
Tue Jan 22, 2019 1:50 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What does Kc have to be less than for you to estimate?
Replies: 3
Views: 65

Re: What does Kc have to be less than for you to estimate?

I would personally use the 5% rule (percent protonation should be less than this) to approximate.
by Arta Kasaeian 2C
Sun Jan 13, 2019 2:41 pm
Forum: Ideal Gases
Topic: Units
Replies: 19
Views: 242

Re: Units

The temperature is always plugged in as Kelvin. If the question concern the change in temperature in celsius, you calculate using kelvins and convert to celsius in the last step.
by Arta Kasaeian 2C
Sun Jan 13, 2019 2:37 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changes in Partial Pressure
Replies: 5
Views: 101

Re: Changes in Partial Pressure

I think in our textbook the temperature is assumed to be stationary because if it changes everything else in the equation changes and with it so does K equilibrium constant.
by Arta Kasaeian 2C
Sun Jan 13, 2019 1:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: (aq) in calculating K
Replies: 9
Views: 111

Re: (aq) in calculating K

Generally when (aq) is posted we are bound to calculate the Equilibrium Constant (Kc) using the concentration of the compounds. Beware that when (aq) is used, there may be a solvent especially water (H2O) in which point we don’t consider its concentration in our formula because its mass is too big a...

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