WEBVTT
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All right, so we're asked to find the temperature
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at which this reaction will be spontaneous. So the
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best way to do that is to set our equation
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. Delta G, um, equals don't h minus
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T Delta s 20 So what we're gonna have to
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do is find Delta h and Delta s of reaction
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for our reaction here. So let's start off of
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finding the Delta h of reaction again. We're gonna
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use our equation of products minus reactant, and I
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always like to write out a little skeleton here,
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so I don't get confused. So we're gonna have
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to Delta f information or the Delta H of formation
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of C two h two plus the adult age information
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of age two plus the Delta H information reached 20
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minus. These are all these are all our X
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and then minus or react insists the Delta H information
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of ch four and the Delta H of formation of
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Oh, to remember when we have coefficients in our
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equation, we always need to put them in our
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products minus reactant. That is, on a coefficient
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. Our products minus reaction equation. So we are
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going to put a two here, so two times
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developed age information of H two. And then we're
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going to have to hear times two and times,
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one half Great. So you can find the Delta
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H informations most like being the appendix of your textbook
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. You can also google them. Um, I
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have filled in the little skeleton the years, so
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these values correspond to the built age formation of these
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molecules. Up here again, we're gonna want to
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add in our coefficients do that again. It's always
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good practice on half. Great. So if you
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want to pause the video and do that calculation really
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quickly, you should get a Delta age of reaction
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of, ah, 134 0.914 killer jewels. And
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since we know we're going to put this in an
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equation with Delta s, which is in jewels,
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were gonna want to change our Delta H into jewels
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so that we have the same units throughout. So
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again, we're just gonna multiply by 1000 and will
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get 134 914 Jules Great. So we're going to
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do the exact same thing. We're Goto s reaction
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now. So again, I wrote on our little
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skeleton and let's fill in our I'll just do this
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. Um, our coefficients times two times. One
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half great again. I have provided the standard entropy
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use for all of these, But again, they
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should be in your, um, in textbook where
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you can find them online. So fill in our
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coefficients times two half. If you want to pause
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the video and do that calculation really quick, you
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should get a standard entropy. Uh, 176 0.7
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jewels. Great. So now we're gonna again use
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the equation above Delta G equals Don't age minus t
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Built s. So again, we're cell setting Delta
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G 20 We're gonna fill in our delta age and
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jewels. So 1000 134,000 914 jewels minus X is
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temperature. That's what we're solving for. And 176.7
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jewels. Great. And that should come out to
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be a temperature of 775 Kellman. So above this
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temperature, the reaction will be spontaneous. All right
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. So be asks us to find the temperature at
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which the formation of a pseudo lean will be spontaneous
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again. This is from its component parts. So
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we're gonna have C plus H two. And remember
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, we always have to balance our equations. Never
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assume they're balanced. So that is just going to
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be putting a to see here. So we have
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to seize on this side to H is on the
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side. To seize to H is perfect. Now
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we're gonna do the exact same thing again. We're
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wanted gonna want to get our Delta H in Delta
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s so we can set our Delta G equals Delta
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H minus T. Delta s Sorry. That's a
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little messy. We're gonna set Delta G 20 again
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. So we're gonna want to find our Delta h
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of reaction and our delta acid reaction. So let's
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start with our Delta H again. It's always products
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minus reactions. You want to drill that into your
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brain products minus reactant have my little skeleton here and
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again. Always remember to fill in the coefficient.
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So again, we have a two there, so
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we're gonna put it into our equation. So I
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have not provided the standard h of formation or the
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standard age. Yeah, the standard entropy of formation
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. But again, you should be able to find
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them in your textbook. And if you want to
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pause the video, do that calculation. They should
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come out to me. 227. Kill it,
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Jules. And just like last time, we're gonna
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want to change this into jewels. Since we know
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that Delta s is usually given in jewels, so
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that is going to come out to be 200 27,000
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, Jules. Great. And now we're gonna do
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the X. The same exact thing with our standard
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enter peace. So again, remember, to code
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are coefficients, and I haven't provided the standard entropy
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use. But again, they should be in your
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textbook, or you can google them. So pause
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video and do that quick calculation, and you should
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get 58.8 jewels. All right, You know where
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we're going from here? We're gonna plug it in
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to our equation up here again. So again,
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we're setting Delta G 20 So when you're trying to
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find the temperature that a reaction becomes spontaneous, you're
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always going to sell to set your Delta G 20
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out. So we have 227,000 kill it, er
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, jewels on this for a delta H and then
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X is going to be our temperature we're solving for
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. And then we have 58.8 jewels over there and
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then solving for X, we should get a T
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equals 385. Excuse me. 3855 point for Calvin
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and above this temperature of the reaction will be spontaneous
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. All right, So for the last question,
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we know that it's asking us about this initial equation
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up here. This is how they make a settling
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, um, in a lab. I think it
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says yes. Okay, so we know it.
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We're told that this process happens at 15 100 degrees
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Celsius, which is about adding 273 to changes into
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Calvin Ah, 170 our 1000. Gosh, I'm
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having a rough day 1773 Calvin. And from the
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first part of this question, we know that above
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775 we Kelvin, the reaction will be spontaneous.
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So we know that at this temperature the reaction will
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be spontaneous. That means that it's just going to
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continue going. It doesn't need any input of energy
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. So we want to cool the reaction reaction.
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So we know that the reaction will stop. Because
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by cooling this down, once we get below 775
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Calvin, the reaction is no longer going to be
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spontaneous, so we're able to stop it.