Search found 30 matches
- Sun Mar 17, 2019 8:59 pm
- Forum: Balancing Redox Reactions
- Topic: Triprotic
- Replies: 7
- Views: 3186
Re: Triprotic
It’s phosphoric acid and I can’t believe I got it right holy wow
- Mon Mar 11, 2019 11:45 am
- Forum: Ideal Gases
- Topic: Ideal gases
- Replies: 5
- Views: 195
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”
- Mon Mar 11, 2019 11:43 am
- Forum: Zero Order Reactions
- Topic: Graphs
- Replies: 6
- Views: 490
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.
- Mon Mar 11, 2019 11:42 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: molecularity
- Replies: 8
- Views: 412
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
- Mon Mar 11, 2019 11:38 am
- Forum: Biological Examples
- Topic: Enzymes, Lecture example.
- Replies: 3
- Views: 446
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
- Mon Mar 11, 2019 11:25 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constanst
- Replies: 3
- Views: 144
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.
- 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: 192
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.
- 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: 139
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...
- Wed Feb 27, 2019 4:40 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Comma versus line
- Replies: 1
- Views: 87
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.
- Wed Feb 27, 2019 4:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt (s) [ENDORSED]
- Replies: 8
- Views: 418
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.
- Wed Feb 27, 2019 3:46 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidized vs oxidizing agent
- Replies: 6
- Views: 220
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.
- Wed Feb 27, 2019 3:39 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n
- Replies: 8
- Views: 383
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...
- Wed Feb 27, 2019 3:27 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: flipping the sign of Ecell
- Replies: 5
- Views: 263
Re: flipping the sign of Ecell
Yes, if needed to change calculate oxidation potential, you must switch the sign of the reduction potential.
- 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: 2923
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.
- Wed Feb 27, 2019 3:21 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 4
- Views: 196
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...
- Sun Feb 10, 2019 10:15 pm
- Forum: Phase Changes & Related Calculations
- Topic: Celsius and Kelvin
- Replies: 6
- Views: 271
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.
- 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: 205
Re: Entropy and Enthalpy
Entropy is essentially the measure of change of enthalpy over temperature so I'd assume you can tell through that.
- Sun Feb 10, 2019 9:42 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm 2019
- Replies: 9
- Views: 373
Re: Midterm 2019
The midterm covers until entropy but doesn't include gibbs free energy.
- Sun Feb 03, 2019 2:20 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Biological Systems
- Replies: 3
- Views: 205
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
- Sun Feb 03, 2019 2:15 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: kJ vs J
- Replies: 9
- Views: 306
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.
- Sun Feb 03, 2019 2:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam resulting in burns?
- Replies: 6
- Views: 311
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...
- 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: 189
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.
- Sun Jan 27, 2019 10:38 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE Box Ratios
- Replies: 8
- Views: 510
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.
- 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: 157
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...
- Tue Jan 22, 2019 1:57 am
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic or Exothermic
- Replies: 20
- Views: 983
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.
- Tue Jan 22, 2019 1:53 am
- Forum: Ideal Gases
- Topic: ICE Table Values
- Replies: 9
- Views: 532
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.
- 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: 167
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.
- Sun Jan 13, 2019 2:41 pm
- Forum: Ideal Gases
- Topic: Units
- Replies: 19
- Views: 473
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.
- 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: 209
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.
- Sun Jan 13, 2019 1:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: (aq) in calculating K
- Replies: 9
- Views: 257
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...