text
stringlengths 19
206
|
|---|
Xt-yom79grM-018|So you would guess that this reaction in the standard state must favor the reactants.
|
Xt-yom79grM-019|The pressure is too high.
|
Xt-yom79grM-020|1 atmosphere is too high a pressure for 25 degrees C.
|
Xt-yom79grM-021|So, we're going to favor the reactant.
|
Xt-yom79grM-022|That means delta G will be positive.
|
Xt-yom79grM-023|Delta G positive in the standard means K has to be less than 1.
|
Xt-yom79grM-024|Those two things go together by our definition of delta G standard is minus RTLNK.
|
Xt-yom79grM-025|So, I can make the correlation that delta G is bigger than zero, and K is less than 1.
|
Xt-yom79grM-027|And it's equal to the equilibrium constant.
|
Xt-yom79grM-028|So, I could have started from that direction and said, the equilibrium constant for this reaction at 25 degrees C is less than 1.
|
Xt-yom79grM-029|That means the standard state free energy difference must be greater than zero.
|
Xt-yom79grM-031|And that's what I'm looking at.
|
Xt-yom79grM-032|So, in either case, standard state free energy, greater than zero.
|
QL6TFnaXvMg-000|Let's look at a can of a carbonated beverage that's been, say, left in the back of a car and it's warmed up.
|
QL6TFnaXvMg-001|A warm day, carbonated beverage expands.
|
QL6TFnaXvMg-002|So you'll notice the can is larger, about ready to pop.
|
QL6TFnaXvMg-003|What does that mean about the dissolution of carbon dioxide?
|
QL6TFnaXvMg-011|We're talking about carbon dioxide gas dissolved in a carbonated beverage.
|
QL6TFnaXvMg-012|As the beverage warms, the can expands.
|
QL6TFnaXvMg-013|Now, the can expands because carbon dioxide is coming out of solution.
|
QL6TFnaXvMg-014|You might have thought, well, the can expands because there's a little gas in the can and that warms up and that expands.
|
QL6TFnaXvMg-015|But the amount of gas in the can is very small, so it doesn't account for all the expansion of the can.
|
QL6TFnaXvMg-016|The big factor accounting for the expansion of the can is carbon dioxide in the solution coming out and creating a larger volume of carbon dioxide.
|
QL6TFnaXvMg-017|And why would that happen?
|
QL6TFnaXvMg-018|Well, as you warm it, if this is an exothermic reaction, heat would be a product.
|
QL6TFnaXvMg-019|Then warming it would cause the reaction to shift back towards reactants-- the carbon dioxide gas.
|
pKQgwIPlNL4-000|Let's look at the equilibrium in the bloodstream between hemoglobin, carbon monoxide, and oxygen.
|
pKQgwIPlNL4-001|Now, carbon monoxide bonds strongly to hemoglobin.
|
pKQgwIPlNL4-002|And that's why carbon monoxide is poison.
|
pKQgwIPlNL4-003|It can displace the oxygen from your blood and replace it with carbon monoxide.
|
pKQgwIPlNL4-004|That ties up that oxygen-carrying molecule.
|
pKQgwIPlNL4-005|And even though you could breathe in and out, you can't bind any of the oxygen you're breathing in.
|
pKQgwIPlNL4-006|So you can actually suffocate while you breathe because carbon monoxide has bound the hemoglobin.
|
pKQgwIPlNL4-007|The question I have for you is, how could you reverse that?
|
pKQgwIPlNL4-008|What's the best procedure?
|
pKQgwIPlNL4-016|We're looking at the reaction between hemoglobin oxygenated and carbon monoxide.
|
pKQgwIPlNL4-017|Carbon monoxide strongly binds the hemoglobin and displaces oxygen. What we're looking for is a strategy to reverse that.
|
pKQgwIPlNL4-018|So our options are increase the partial pressure of oxygen.
|
pKQgwIPlNL4-019|And if we increase the partial pressure of oxygen, that's a product.
|
pKQgwIPlNL4-020|Increasing something on the product side will tend to shift the reaction back towards reactants.
|
pKQgwIPlNL4-021|Increasing a product will automatically make Q larger than K. You're increasing the numerator.
|
pKQgwIPlNL4-022|If you increase the numerator, what do you need to do?
|
pKQgwIPlNL4-023|Shift back towards reactants, increase the size of the denominator, decrease the size of the numerator, a shift back towards reactants.
|
pKQgwIPlNL4-024|We could also just look at it as you put something on this side, the reaction we want to shift back towards this side.
|
pKQgwIPlNL4-027|You will put an oxygen mask, have them breathe pure oxygen.
|
pKQgwIPlNL4-028|That increases the partial pressure of oxygen and drives the carbon monoxide out of the system.
|
pKQgwIPlNL4-029|So here, the correct answer, increase the partial pressure of oxygen.
|
V_0Bnc_URos-000|What causes condensation in a real gas?
|
V_0Bnc_URos-001|Well, in an ideal gas, the particles don't interact.
|
V_0Bnc_URos-002|There's no attraction or repulsion energy between them.
|
V_0Bnc_URos-003|In fact, if you plotted their interaction energy versus distance, it would be very boring.
|
V_0Bnc_URos-004|There's no interaction energy, regardless of the distance between the ideal gas particles.
|
V_0Bnc_URos-005|For real gas particles, there is an interaction energy.
|
V_0Bnc_URos-009|Large distances, the interaction between the particles, isn't very important.
|
V_0Bnc_URos-010|As the particles get closer, that interaction energy is more important.
|
V_0Bnc_URos-011|And you'll see, the plot goes to a stabilization energy as the particles get closer.
|
V_0Bnc_URos-012|As the particles get very close, then that interaction energy becomes unfavorable.
|
V_0Bnc_URos-013|That is, there's an actual repulsion.
|
V_0Bnc_URos-014|You can't push the particles on top of each other.
|
V_0Bnc_URos-017|And this attraction energy, if that is higher than the kinetic energy of the particles, then the particles can actually associate.
|
V_0Bnc_URos-018|That is, for low attraction energies, the kinetic energy is larger than the attraction energy, and the kinetic energy of the particles overwhelms the attraction energy.
|
V_0Bnc_URos-019|But as the kinetic energy goes down-- and how do I lower kinetic energy?
|
V_0Bnc_URos-020|Lower the temperature.
|
V_0Bnc_URos-021|As I lower the kinetic energy, then the attraction energy becomes a more important factor, and the particles associate.
|
V_0Bnc_URos-022|That's the nature of condensation.
|
o6fk49PNN2s-000|The natural direction of a process is determined by the entropy change in the universe, but it's difficult to track the entropy of the system in the surroundings.
|
o6fk49PNN2s-001|So we'd rather have an expression that involves just the system.
|
o6fk49PNN2s-005|Now, this entropy of the surroundings.
|
o6fk49PNN2s-006|What's happening in this reaction?
|
o6fk49PNN2s-007|Well, water liquid is changing into water gas.
|
o6fk49PNN2s-008|In order for that to happen, heat needs to flow from the surroundings into the system.
|
o6fk49PNN2s-009|How much heat?
|
o6fk49PNN2s-010|Well, the enthalpy of vaporization of water.
|
o6fk49PNN2s-011|So I can write this entropy change of the surroundings in terms of the enthalpy change in the system.
|
o6fk49PNN2s-012|And I'm going to give it a negative sign because it's the surroundings that's sending heat into the system, so the surroundings is losing heat.
|
o6fk49PNN2s-018|So when minus delta S is less than 0, the forward direction is favored by the universe.
|
o6fk49PNN2s-021|And when the Gibbs free energy of the system is less than or equal to 0, the forward process is favored.
|
o6fk49PNN2s-022|When it's equal to 0 exactly, you're in equilibrium.
|
LOSpsszfwWU-000|Let's look at the effect of temperature on a chemical reaction from a kinetic standpoint.
|
LOSpsszfwWU-001|So for the following chemical reaction, the forward rate constant is larger than the reversed rate constant-- this chemical reaction here.
|
LOSpsszfwWU-002|What does that mean about the equilibrium constant for an increase in temperature?
|
LOSpsszfwWU-011|We're looking at the effect of temperature on an equilibrium constant from a kinetic standpoint.
|
LOSpsszfwWU-012|So the equilibrium constant is the ratio of K forward to K reverse, the rate constants.
|
LOSpsszfwWU-013|So we should be able to predict the temperature effect on that equilibrium constant.
|
LOSpsszfwWU-015|This doesn't give us the whole rate.
|
LOSpsszfwWU-017|But, what this ratio tells us is that the rate constant for the forward is larger.
|
LOSpsszfwWU-018|That means the activation energy for the forward is smaller.
|
LOSpsszfwWU-019|There is a lower barrier, that's what makes the forward reaction intrinsically faster.
|
LOSpsszfwWU-020|The reverse activation energy is slightly larger.
|
LOSpsszfwWU-024|The larger the activation energy, the more sensitive the rate constant is to a change in temperature.
|
LOSpsszfwWU-025|So for a large activation energy, K changes a lot with a small change in temperature.
|
LOSpsszfwWU-029|This one will change more dramatically.
|
LOSpsszfwWU-030|This will get larger with temperature faster.
|
LOSpsszfwWU-031|That will make the overall equilibrium constant get smaller with an increase in temperature.
|
LOSpsszfwWU-032|So for this, the equilibrium constant decreases with temperature.
|
LOSpsszfwWU-033|Now there's another way you could have looked at that.
|
LOSpsszfwWU-035|And if it's exothermic, heat is a product.
|
LOSpsszfwWU-036|I increase the temperature, that favors the reactants and leads to a decrease in equilibrium constant.
|
LOSpsszfwWU-037|Two arguments that lead to the same conclusion for the equilibrium constant and temperature.
|
ESX5q4FtkAo-000|For a sample of gases, even if that's a mixture of gases, the gases have the same pressure and the same kinetic energy, as long as they're at the same temperature.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.