Search found 32 matches
- Sun Mar 17, 2019 1:20 am
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 8
- Views: 1150
Re: K and Q
The concentration of solids and liquids are unchanged in a reaction. so only gasses are included.
- Sun Mar 17, 2019 1:18 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: pseudo rate law
- Replies: 7
- Views: 1119
Re: pseudo rate law
Pseudo rate law is just a method used to simplify second order reactions that have more than one reactants. You basically take one reactant in a very high concentration, so the second reactant seems insignificant compared to it and doesnt have a big impact on the rate law of the equation. Therefore ...
- Thu Mar 14, 2019 11:19 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding an Inert Gas
- Replies: 4
- Views: 614
Re: Adding an Inert Gas
An inert gas does not react with any of the compounds in the reaction, however it does increase . the pressure of the overall system. Since the amount of reactants/products doesnt change, their partial pressures remain the same and so the rates the the forward and backward reaction dont change either.
- Thu Mar 14, 2019 11:17 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Old chemists never die, they just stop reacting.
- Thu Mar 14, 2019 11:16 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Q: What do you call a tooth in a glass of water?
A: One molar solution.
A: One molar solution.
- Thu Mar 14, 2019 11:15 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Did you know that you can cool yourself to -273.15˚C and still be 0k?
- Thu Mar 14, 2019 11:14 pm
- Forum: Zero Order Reactions
- Topic: Order distinction
- Replies: 9
- Views: 1127
Re: Order distinction
You take into account the rate law . equation. the sum of the exponents of the reactants gives you the order.
- Thu Mar 14, 2019 11:12 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: catalyst vs intermediate
- Replies: 9
- Views: 907
Re: catalyst vs intermediate
A catalyst is added to the reaction to make it faster, it is part of the reactants but then is regenerated. An intermediate is formed in the reaction and then used up, it does not need to be specifically added.
- Sun Feb 24, 2019 5:28 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Predicting Standard Potential of Cells
- Replies: 3
- Views: 794
Re: Predicting Standard Potential of Cells
If the value for the reverse reaction is given, you can take the negative value, which would give you the oxidation potential for the reaction you need that you can plug in the other equation, Ecell= Ered + Eox
- Sun Feb 24, 2019 5:25 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Determining what is constant
- Replies: 1
- Views: 242
Re: Determining what is constant
Most of the time, it is stated if there is a change. Like if there isa change in volume or temperature, the question will state that it went from this value to this value. But if its just a single value given, it is assumed its constant because there is no change indicated, unless ofcourse we need t...
- Sun Feb 24, 2019 5:21 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Spontaneous?
- Replies: 6
- Views: 770
Re: Spontaneous?
you look at the change in Gibbs Free Energy (Delta G). if the value is negative, it is a spontaneous reaction, also called exergonic. if it has a positive value it is not spontaneous, also called endergonic.
- Sun Feb 24, 2019 5:18 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation
- Replies: 4
- Views: 575
Re: Oxidation
Its kinda of a process that was evolved from a more basic concept (kind of like the definition of Lewis Acids and /bases, going from giving or receiving H+ or OH- to a more broad one.) Similarly, the definition of oxidation was originally the addition of oxygen to a compound or the removal of Hydrog...
- Sun Feb 24, 2019 5:12 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n value
- Replies: 11
- Views: 967
Re: n value
n is the number of moles so it would either be given to us or we calculate it using molar mass or using the ideal gas law( in which case Pressure Volume and Temperature will be given.)
- Sun Feb 24, 2019 5:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: gibbs free energy
- Replies: 5
- Views: 619
Re: gibbs free energy
Most of the times, we use Gibbs Free Energy to tell us about the spontaneity of a reaction. It is . state function and gives us a relationship between Enthalpy and Entropy. we say a reaction is spontaneous if its change in G is negative.
- Sun Feb 10, 2019 2:34 pm
- Forum: Calculating Work of Expansion
- Topic: Using Derivative/Integral Equations
- Replies: 5
- Views: 581
Re: Using Derivative/Integral Equations
The integrals are only for derivations. We . wont be asked to derive the equations, only to use them in solving problems
- Sun Feb 10, 2019 2:32 pm
- Forum: Calculating Work of Expansion
- Topic: Integrals
- Replies: 3
- Views: 369
Re: Integrals
I dont think we need to learn the derivations, but it may be a good idea to see where the relations came from and what conditions they are valid in
- Sun Feb 10, 2019 2:30 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Q: What do you do with a sick chemist?
A: If you can't helium, and you can't curium, then you might as well barium.
A: If you can't helium, and you can't curium, then you might as well barium.
- Sun Feb 10, 2019 2:30 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Q: What is the chemical formula for "coffee"?
A: CoFe2
A: CoFe2
- Sun Feb 10, 2019 2:29 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Have you heard the one about a chemist who was reading a book about helium?
He just couldn't put it down.
He just couldn't put it down.
- Sun Feb 10, 2019 2:25 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Value of Variable Kb
- Replies: 4
- Views: 934
Re: Value of Variable Kb
Kb is a constant value, the boltzmann Constant. The value will always be given, we dont need to memorize it. but it helps determine the entropy of a system
- Sun Feb 10, 2019 2:24 pm
- Forum: Calculating Work of Expansion
- Topic: Degeneracy
- Replies: 3
- Views: 366
Re: Degeneracy
Degeneracy is the number of possible ways to attain a certain energy state, like the number os electron configurations that can require the same energy level. This can be used to then determine entropy and spontaneity of a reaction
- Sun Feb 10, 2019 2:20 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H
- Replies: 4
- Views: 429
Re: Delta H
q and H are interchangeable terms. Heat is the same thing as Enthalpy. However q is equal to U only when no work is done.
- Sun Feb 10, 2019 2:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 11
- Views: 1479
Re: Phase Changes
Yes it is very important to understand the phase changes as a lot of the times questions may ask the complete heat difference of a phase change and at the time you need to be conscious of the heat required for changing phase even though the temperature does not change.
- Sun Feb 10, 2019 2:14 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Decreasing volume and chemical equilibrium
- Replies: 8
- Views: 942
Re: Decreasing volume and chemical equilibrium
If you increase the volume, the reaction will most likely shift to the side with fewer moles
- Thu Jan 24, 2019 5:12 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 4026810
Re: Post All Chemistry Jokes Here
Helium walks into a bar,
The bar tender says "We don't serve noble gasses in here."
Helium doesn't react.
The bar tender says "We don't serve noble gasses in here."
Helium doesn't react.
- Thu Jan 24, 2019 5:10 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: using Ka and Kb to predict strengths of acids and bases
- Replies: 3
- Views: 530
Re: using Ka and Kb to predict strengths of acids and bases
yes, the same concept will apply to bases. If Kb<10^-3, the base would considered weak. Similarly, if Kb>10^-3, the base is considered strong
- Thu Jan 24, 2019 5:08 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why steam causes severe burns
- Replies: 9
- Views: 2003
Re: Why steam causes severe burns
Think of it this way, when hot water comes in contact with your skin, there will a kind of be a heat energy exchange between the two to bring them to the same temperature, or to equilibrium temperature. Thus the water will cool down and the temperature of skin will rise. Now, as he stated in the wat...
- Thu Jan 24, 2019 5:00 pm
- Forum: Phase Changes & Related Calculations
- Topic: Water heating curve
- Replies: 7
- Views: 776
Re: Water heating curve
during the change of state, there is an initial rise all of the energy supplied through heat is used in breaking bonds, thus there is none residual to increase the temperature. Once all the bonds are broken, then the energy supplied can be used to increase the temperature of the substance as the cha...
- Thu Jan 24, 2019 4:56 pm
- Forum: Phase Changes & Related Calculations
- Topic: Reversible and Irreversible Process
- Replies: 3
- Views: 372
Re: Reversible and Irreversible Process
Most of the time if its a chemical reaction, you can tell by the arrows, if it is an equilibrium arrow, its reversible and if it is a one sided arrow, it is irreversible. However when it comes to change of state and matter, processes like melting and freezing etc are usually reversible as they are t...
- Thu Jan 24, 2019 4:53 pm
- Forum: Phase Changes & Related Calculations
- Topic: Temperature vs. heat vs. energy
- Replies: 4
- Views: 421
Re: Temperature vs. heat vs. energy
Temperature is a measure of the average kinetic energy of a substance whereas heat being transferred.
- Sat Jan 19, 2019 5:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Weak Acid & Salt
- Replies: 4
- Views: 425
Re: Weak Acid & Salt
Because it is a salt, KNO2 will completely dissociate in a solution. Now when you write the reaction both K+ and NO2- show up both sides of the equation, NO2- on the product side does not have the same concentration as the NO2- on the reactant side as it adds up to the concentration of NO2- dissocia...
- Sat Jan 19, 2019 5:18 pm
- Forum: Student Social/Study Group
- Topic: ICE Table
- Replies: 6
- Views: 493
Re: ICE Table
ICE tables are usually used when you are given the initial concentration of a certain substance in the reaction and need to identify the concentration of another substance(usually hydronium or hydroxide ions you need to calculate pH or pOH).