2024 Semester 2 Final Study Guide Supplemental Questions

hey guys welcome back to chemistry second semester final exam study guide so this video's purpose is last year made tutorial videos where walk through every single unit on the study guide and solved all the questions together with you guys but that was for 2023 and for the 2024 school year they are the zville chemistry Department added lot of key Concepts that did not cover on that video last year so this video serves the purpose of answering some of the questions that did not answer on that study guide because they were't there last year so if you guys go through your study guide based on the videos from last year that made you'll notice some of the questions that my study guide from 2023 are you know it's not on there so these questions are there for you guys so that you know at least go over some of this stuff with you so you know what you're doing for your final let's get started always start with the equations review every single equation you're given that call unit zero because you know equations are you know where you start for all these calculations you need your equations to solve the frq portion of your examination so getting started with the first equation you're given here that is P1 V1 that is your combined gas law so you're going to have pressure volume temperature and and moles you won't see moles very often but you might that's so just keep that in mind and you're going to be setting this in proportions so just make sure how to do that algebraically that is the combined gas law next up we have pvnr that is going to be your ideal gas law where is constant it's given there just remember that you're going to be given just randomly solve for unless it tells you to so yeah just keep that in mind next one we have Dalton's law of partial pressures it's saying that the total pressure of container is going to be the sum of this each individual gases pressures pretty simple to use next up we have the mole Road conversion factors we have one mole and particles we have the moles to lers and moles to molar mass remember that the molar mass is going to be in gr per mole and this number comes from your periodic table so it comes from periodic table all right horrible spelling but periodic table right you're going to always use that remember driled this into so grams per mole keep that in mind and then we have analytical stuff with percent yield and percent error so we're going to have for percent yield it's going to be your experimental over theoretical time 100 and then for percent error it's going to be experimental minus theoretical over theoretical * 100 that's going to be in the absolute value form for the experimental minus theoretical for percent error that just means that whatever number you get as percentage if there's negative attached to that percentage just ignore that negative and you'll be fine that's all it's saying next up we have marity and mality capital and lowercase do not confuse those on your test they're there to trick you you don't see mality very often poiter of course Mal marity for concentration mity moles of solute per kilogram of solvent remember that stuff as well and then we have one of my most favorite equations delta equals ikm this is used to solve for your colletive properties so you're going to be solving your boiling point elevation and freezing point depression with these equations just remember that the can be can be the freezing or boiling the in this equation is your vant off Factor always misspell this guy's name believe it's POS goes here factor let me see that factor remember calent compounds have one for that ion compounds is the degree of disassociation of its ions you'll probably see that more often in my previous videos in that respective unit but just quick review and then lowercase of course it's mality so keep that in mind M1 V1 equal M2 V2 the classic dilution equation where is marity even I'm getting confused marity and is volume right so as long as your volume's in the same unit for V1 and V2 you can use either milliliters or liters just make sure you know keep that in mind you can't just go use liters and milliliters at the same time they have to be the same unit all right and my favorite equation as well equals MC delta right qal MC delta that is your thermodynamics or thermochemistry equations to calculate heat which is this is for the phase changes and then this is your Gibs free energy calculation remember is entropy temperature Delta is enthalpy and yeah then we have the pH calculations pH is negative log of the concentration of your H+ ions is the negative log of the concentration of your minus ions that of course you should all know by now you can go back and forth from the H+ concentration to the pH by using the log it's just log math if you're in calcul calus or pre-calculus you should probably know this well it's very simple log math your calculator would do it all for you you just need to know these formulas and there's the same for pH or and same for H+ and minus you just got to know how to use them remember that when you raise it to the the power there's negative in front of that so when you raise it to 10 to the power right that is going to be 10 the power right and the Su of the ph and will be 14 remember that if your pH is less than seven it is acidic and if your pH is greater than seven it is going to be basic so that's the basically the you know really really quick and rushed rundown of your equations yeah so let's get started with unit one right get this over with all right unit one is the states of matter and gas laws there was one question that did not answer on that last year's video and so let's go over it now Define the following freezing melting boiling condensing sublimation deposition evaporation and STP so we all know that freezing is when we go from let me just write this to the side freeze freezing we're we're going to freezing is we're going to go from liquid to solid right and so that is going to be freezing melting is going to be and we'll talk more about this in thermm later on we're going to talk about endothermic and exothermic so we're not going to know mention that too much right now so this melting we're going to go from solid to liquid right boiling we're going to go from boiling we're going to go from liquid to gas condensing we're going to go backwards condensing we're going to go from gas to liquid sublimation sublimation that's big word sublimation did even spell that correctly yes did sublimation we're going to go directly from solid to gas deposition is backwards deposition we're going to go from gas to solid evaporation this is key concept let me actually move it over to the side here little bit so evaporation is funny concept right and you guys talk more about this in AP Chemistry if you decide to take it but evaporation is interesting because say you have liquid in container right that's beaker and you have container and your solute is what's it called or Sal like the liquid solution is going to be evaporating right and certain level of particles reaches into that and exerts pressure right and once that pressure reaches equilibrium that pressure will directly imp so that this pressure is called vapor pressure right and so when your vapor pressure is in equilibrium with the amount of evaporation occurring then you're going to have equilibrium and then that's just saying that know you're evaporating as much as you're un evaporating the liquid it's kind of doesn't make sense if you hear it this way but it's it's strange concept and recommend that you go back into your notes actually and look at evaporation as part of your gas laws just you do need to know vvor pressure and you need to know equilibrium relating to evaporation so keep just keep those in mind and then of course we have my favorite standard temperature and pressure standard temperature and pressure have to write this all out cuz it's review guide but standard temp pressure and standard temperature and pressure you're going to be at what the you're going to be at 0° which is 273 Kelvin and 1 atmospheres right and keep that in mind lot of people get confused with room temperature which is 25° so if someone asks you about room temperature that's not sdp room temperature is considered 25° which is 298 Kelvin so just keep that in mind remember just draw line in between that don't get it confused standard temperature is different than room temperature so yeah okay so let's go ahead with unit 4 solution there's one question in unit 4 that did not answer from last year's video and it's just another defining one how boring all right so solute solvent and all that jazz so go ahead and write it up top all right so solute is going to be the stuff you dissolve right and solvent is the stuff that is dissolving the stuff you okay so it's confusing already so let's just write it out solute that is the stuff SL substance you're dissolving you put in to dissolve right that's the solute solvent is the stuff actually doing the dissolving stuff doing the so stuff doing the actual dissolving and this together makes solution we have to talk about unsaturated and saturated so unsaturated easy way to describe this is say you have beaker with the water right like just plain old water and we're going to assume that that amount of water that you have in the beaker Can Only Hold 100 of salt like table salt sodium chloride so anywhere between 0 and 99.99999 right before you hit the maximum amount of solid dissolvable which we said was 100 that is going to be unsaturated so an easy way to define this is can still can dissolve more solute and then when you hit your 100 exactly 100 no more no less you're going to have fully dissolved to capacity and then super saturated of course you're forcing the you're forcing it solution or solvent forcing solvent to the dissolve more than it can take more than capacity that is going to be your super saturated colletive properties you need to know Bing Point El let's just write this out as well cative properties colligative properties my favorite you're going to have boiling point elevation boiling point elevation and this is going to be where the more stuff you put in more solute higher temperature to dissolve or boil is what meant right it's kind of logical right the more stuff you put in the solution the more energy you're going to need to boil that Solution that's boiling point elevation all right let's talk about freezing point depression actually just kidding we're talking about vapor pressure elevation first vapor pressure elevation that's VP we're sorry I'm going crazy vapor pressure depression is what it is all right so that's basically saying that the more solute you put in more Sal you put in the lower the pressure will be the lower the vapor pressure and remember what we talked about evaporation in vapor pressure that's the amount of pressure exerted back onto the solution right the more solute you put in the harder it's going to become evaporated so the vapor pressure will be lowered last but not least we have freezing point depression freezing point depression fpd that's just saying that more Sol the more solute you put in the more solute you put in the lower the temperature you need to freeze and this is the same concept as boiling point elevation right the more stuff you have in it the more energy you're going to need to take out of the the substance or solution or solvent in order to actually freeze the thing because you have more solute in it you have more stuff in it to freeze so you're going to need more energy removed to freeze that solution that's your colligative properties it's not bad just it's just memorization you just if you understand like the concepts of solutions and how that works you're probably going to be fine for the test yeah so last but not least we have to talk about concentrated versus dilute concentrated vs dilute right concentrated you're going to have more solute per solvent right higher marity higher marity and for dilute you're going to have less solvent or solute per solvent consequently your marity will be lower remember that dealing with concentration you're going to be using units in molarity molarity capital for concentration all right just keep that in mind for concentration and you'll be all set all right that covers that question and let's go on to thermochemistry all right so Define the following endothermic and exothermic right easy way to remember this endothermic heat enters the system let's do this in purple endothermic heat heat enters system and exothermic heat will exit the system heat exits system okay that is horrible got to rewrite it okay so for the sign of each endothermic will be positive because you're entering heat in so endothermic is positive exothermic you're releasing heat so it has to be negative it's just memorization thing for specific heat that is the amount of heat required amount heat needed to increase temperature by one whole unit per mass unit of substance so it's the amount of heat it needs to raise the temperature by one whole number unit per mass of unit of substance next up phase change endothermic versus exothermic it can be summarized into Quick diagrams here if you go from solid to liquid to gas this is going to be endothermic right you're increasing heat in order to make it into gas if you go backwards to gas to liquid to solid this is going to be exothermic right you're releasing heat to become lower energized state of phase is what you would say CI says does temperature change during phase change and the answer to that is no with four exclamation marks no no no no temperature does not change during the phase change because that's the moment it's that's when your potential energy changes so it will not have the temperature change no slope is what wanted to say no slope last but not least we have enthalpy per enthalpy for phase changes where Delta Fusion equals Delta solid or solidification and then we have Delta vaporization and then Delta condensation so in this case Delta Fusion refers to to the solid to liquid right solid to liquid so then the this will be positive it's endothermic as we mentioned here next up we have Delta solidification where we go from liquid to solid which will be negative as we go liquid to solid it is exothermic same logic Delta vaporization we go from liquid to gas which of course is endothermic positive Delta sorry Delta condensation right going from gas back to liquid which is negative because we talked about how it is exothermic so that is unit five of thermochemistry that's the only question that was neglected off of that unit so moving forth down to unit six which is rate laws or more officially reaction rates there's crap ton of terms got to Define here so hold on if you will and let me get through these real quick so it says Define the following activation energy activated complex yada yada yada yada okay so let's get started here there's rate law question down here so have to like be aware of space as well why don't we move this out here and we'll just Define it here how's that okay so activation energy is the active energy so activation energy is the energy required needed to start chemical reaction right that's the amount of energy you need to start the chemical reaction the reaction does not start unless that activ activation energy is provided to its fullest extent so think about lighting bunson burner right that methane gas off the tap that's still coming out but what do you need you need is that activation energy provided by the spark with your flint and steel right without that activation energy provided by the spark of the flint and steel you're never going to get that fire to light methane to light on fire so that's good example of activation energy yeah and then we have activated complex right activated complex is going to be write this out give me second activated complex okay activated complex is at the top of your like chemical reaction like the curve right this is where your products are like first formed the point we'll call it the point at which your the point at which the reactants turn into products products and this is at the top of the curve highest point of on curve is what want to say the that is the activated complex next up we have the rate of reaction rate of reaction and the rate of reaction is simple it's it's very simple concept it's measure of the change in the concentration of your disappearance and appearance so elabor in elaboration that's measures the rate at which the concentration of your reactants disappear or your concentration of the products up here that is rate law or rate of reaction it's just measuring the rate at which your concentration of reactants and products disappears and appears respectively Elementary steps these are simple to understand Elementary steps Elementary steps are going to be individual reactions that kind of sum up the overall reaction right so individual reactions that occur prior to the overall reaction so it's just you know the reactions that kind of have to lead up to the overall reaction that is what elementary steps would be and then intermediates give me second to write this intermediates are going to be substances that are made in in the reaction and used up while reaction proceeds so this stuff is like if you make like certain like byproduct but that byproduct is then used used to drive that overall reaction to completion that is an intermediate so say you have like the synthesis of like some random compound and you're making hydrogen in between of it but then immediately after that you use that same hydrogen to make water in order to get to that mysterious compound don't even know what it is that is going to be the intermediate because you're using that you're making it and then using it immediately to get to the final product it's like Gateway the gate way Gateway compounds as you know you would call them so that's intermediates and then we have Gibbs free energy right got to scroll down even more Gibbs free energy Gibbs free energy is Delta is what you would call it that looks like an that's not good Delta that tells you the spontaneity of something spontaneity of substance if Delta is less than zero which means if it's negative it's spontaneous it's spontaneous if Delta is greater than zero not spontaneous and another way for to say spont like to mention spontaneity is going to be thermodynamic favorability right so if it's spontaneous it is thermodynamically favored if it's not spontaneous it is not thermodynamically favored enthalpy and entropy hope you know this by now but enthalpy enthalpy is Delta that's the change in heat is what you would say change in heat change in internal heat and then entropy is Delta and this is the degree of Randomness degree of Randomness the substance or anything it holds so entropy is like the chaos chaos right the degree of chaos and then last but not least we have spontaneous reactions we kind of talked about this with the Gibs free energy but spontaneous reactions spontaneous reactions spontaneous reactions are going to be like Delta is negative is negative and is thermodynamically favored big words big words but that just saying that it it tends to occur more naturally in the Natural State rather than you having to force it by plugging in other extraneous sources of energy to make that equation or chemical reaction happen so that's just what it means by spontaneous reactions all right so that's that and then continuing on with the unit 6 reaction rates we have evaluations of increases and decreases in entropy right so for entropy so we have think we have space to just straight right on here includ in my favorite color purple here so if you heat water from 0 to 20° right you're increasing might have to erase this stuff it's lagging okay so just going to grab this eraser and erase this stuff there we go right all right we have increases and decreases in eng ropy right so we have here if we heat water from 0 to 20° we're increasing the movement of the molecules of water right from Frozen to liquid state we're increasing the amount of movement that occurs which means that it there's an innate increase in chaos that means there is an increase in entropy next we have decomposition reaction decomposition reaction is where one molecule splits into its respective components that separates into two parts which is two separate molecules which are innately more have more entropy so you're increasing the degree of entropy in this as well next we have gas condensing into liquid right if you're going from gas to liquid you're going to have decrease in entropy because this is from going to gas to liquid this is an exothermic process and you're going to be releasing all that energy and so you're going to be less chaotic in movement in the particles associated with the substance therefore it will be decrease in entropy and last but not least we have solid dissolving in water this is an increase in entropy and let me explain why if you have solid solute that dissolves in the water liquid solvent your solid solute had less movement as solid form but now it's dissolved in water which means that it takes into account the properties of the liquid water which means that it's going to be moving more chaotic than before so you're increasing entropy all right question six says given the following data you're going to be determining the rate law this is an fq question and it's good to know how to solve these questions which I'll show you have not solved this beforehand so we'll see how this goes so we have plus yields right and so the goal to this is to find the experiment where changes but stays constant so for example here experiment 1 and two changes from 0.015 to 03 but remains constant at 0.01 that is the the the thing you want to use that that that's what you want to use to figure out for so if we have we're going to set this the higher number goes on top 0.015 goes on the bottom and we're going to set that as and this format is the same for all rate laws so you just have to memorize this or write it down somewhere and you know brain dump us before the exam so whatever number corresponding with 03 we're just going to put on top as well 3.4 * 104 on top and 8.5 * 105 on the bottom when we divide this if we divide 03 by 015 we're going to get 2 2x equal and then we divide 3.4 * 10 -4 by 8.5 * 105 when we get 4 so here if you raise two to the second power you get four right 2 * 2 is if you raise 2 by the second power it's four therefore is 2 so this is second order for in the same way we can calculate for as well we want something where it changes for but remains constant in remember the higher number also goes on top so we have 04 over 0.01 this is experiment two and three cuz changes from 0.04 to 01 but remains constant at 0 015 so this one we're going to set to and remember the higher number or the higher number concentrated the rate law we're just going to put on top it's 3.4 * 10 4 over 8.5 * 105 right and so if we divide 004 by 01 we're going to get four 4 equals and this is four this the same numbers from the previous so we can just carry that over because we know it's four so in this case equals 1 so that's first order 4 Because if we raise four to the first to the first power you're still going to get four so the rate law for this is you just take into account both of these so it's second order for and first order for so the rate law is always going to start with rate equals and then the concentration of raised to the second power because it's second order and raised to the first Power for because the concentration is first order so that is your rate law you don't really need that one there it's nice to have mean it's not nice but if you if it makes you understand better go Ahad and keep it on there but I'm going to take it off Cu it's understood that it's just one the overall order for this reaction is calculated by adding up all of its respective orders so we had order two second order for and first order for so 2 + 1 is three and there for its third order overall all right and last but not least we have to solve 4K so in order to do this we literally just grab this equation choose an experiment and just plug it in so we're just going to take into account the first experiment because always do the first experiment it's just the first one down the list so we have rate equal * a^ 2 * so rate in this case is 3 .4 * 104 equal * the concentration of 0.03 remember that's this number right there 0.03 squared time 0.01 for concentration of so when we solve this 0.03 2ar time 01 will give you this number here three so if we write this again 3.4 * 104 = * 9 * 10 -6 so if we divide this by 9 * 10 -6 we're going to get and in this case will be 3.4 * 104 / * that and your will be 37777 we're just going around that to 37.78 there's no unit for cuz it's constant and that is your value for this scenario all right moving on scrolling just little bit here make room for that Delta question here so we have reaction has Delta of 37.1 KJ per mole and Delta of 106.8 je per Kil or kin time Mo would this reaction be spontaneous at 250° so all we have to do in this scenario is literally plug and chop so we have Delta gal Delta minus Delta in this case Delta we're finding equals Delta is 37.1 minus temperature this has to be in kelvin so plus 200 73 will give you 523 Kelvin so times the Delta the entropy 106.8 right so 523 * 106.8 is very big number 37.1 minus 55856 point4 right 37.1 minus that will give you Delta = 19.3 and of course that Delta value is negative so therefore this reaction is spontaneous is spontaneous because Delta is negative it is thermodynamically favored and therefore SP continuous last but not least we have unit8 for acids and bases this is the last question we're going to go over so we're going to Define what bronzed Lowry acid and base is it doesn't say Define the acid but we're going to go ahead and Define the base and acid anyways so bronzed Lowry acid is going to be the H+ donator and the bronzed Lowry base is going to be the H+ recipient Receiver right so if your acid is HCl right so that H+ is going to be donated to the base donated to base and the base will receive the H+ ions from the acid and that is the very simple definition of bron stead Lowry ass acid and base that wraps it up for all of the questions that were neglected due to the changing curriculum for the 2024 final exam study guide for second semester for chemistry hope this helped leave questions in the comments I'll try my best to answer them and good luck on your finals thanks for watching