[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.18,0:00:01.14,Default,,0000,0000,0000,,- [Presenter] Your\Nfriends are coming over.
Dialogue: 0,0:00:01.14,0:00:03.09,Default,,0000,0000,0000,,So you decide to make\Nsome Kool-Aid for them.
Dialogue: 0,0:00:03.09,0:00:06.66,Default,,0000,0000,0000,,You happen to have a very\Nconcentrated Kool-Aid solution.
Dialogue: 0,0:00:06.66,0:00:09.24,Default,,0000,0000,0000,,This is the molarity of the\Namount of sugar that you have,
Dialogue: 0,0:00:09.24,0:00:12.72,Default,,0000,0000,0000,,so this is four moles of sugar per liter,
Dialogue: 0,0:00:12.72,0:00:15.96,Default,,0000,0000,0000,,which is apparently a very sweet syrup,
Dialogue: 0,0:00:15.96,0:00:17.43,Default,,0000,0000,0000,,you don't wanna drink that directly.
Dialogue: 0,0:00:17.43,0:00:18.57,Default,,0000,0000,0000,,So what you're gonna do,
Dialogue: 0,0:00:18.57,0:00:20.70,Default,,0000,0000,0000,,well, of course you\Nare going to dilute it.
Dialogue: 0,0:00:20.70,0:00:22.23,Default,,0000,0000,0000,,So you're gonna take a jug,
Dialogue: 0,0:00:22.23,0:00:24.21,Default,,0000,0000,0000,,you're gonna add some of this over here
Dialogue: 0,0:00:24.21,0:00:25.80,Default,,0000,0000,0000,,and then you're gonna add a lot of water
Dialogue: 0,0:00:25.80,0:00:29.19,Default,,0000,0000,0000,,and that'll give you a much\Nmore drinkable, dilute solution
Dialogue: 0,0:00:29.19,0:00:30.74,Default,,0000,0000,0000,,that you can serve to all your friends.
Dialogue: 0,0:00:30.74,0:00:33.18,Default,,0000,0000,0000,,Now, let's say you wanna\Nmake about, I don't know,
Dialogue: 0,0:00:33.18,0:00:36.57,Default,,0000,0000,0000,,five liters of this solution,\Nthis drinkable Kool-Aid,
Dialogue: 0,0:00:36.57,0:00:40.17,Default,,0000,0000,0000,,and let's say the concentration\Nfor it to be drinkable
Dialogue: 0,0:00:40.17,0:00:41.97,Default,,0000,0000,0000,,needs to be about 0.2 molar,
Dialogue: 0,0:00:41.97,0:00:43.80,Default,,0000,0000,0000,,so that's the molarity of the sugar
Dialogue: 0,0:00:43.80,0:00:46.96,Default,,0000,0000,0000,,that you want in this Kool-Aid solution.
Dialogue: 0,0:00:46.96,0:00:49.08,Default,,0000,0000,0000,,So the big question we\Nwanna try and answer
Dialogue: 0,0:00:49.08,0:00:51.06,Default,,0000,0000,0000,,is, in order for this to happen,
Dialogue: 0,0:00:51.06,0:00:53.31,Default,,0000,0000,0000,,in order for you to get\Nthis diluted solution,
Dialogue: 0,0:00:53.31,0:00:55.89,Default,,0000,0000,0000,,how much of the concentrated\Nsyrup should you take?
Dialogue: 0,0:00:55.89,0:00:58.67,Default,,0000,0000,0000,,What should be the volume that\Nyou should take over here?
Dialogue: 0,0:00:58.67,0:01:00.54,Default,,0000,0000,0000,,So that after you add water
Dialogue: 0,0:01:00.54,0:01:03.21,Default,,0000,0000,0000,,and fill it up all the way to five liters,
Dialogue: 0,0:01:03.21,0:01:06.20,Default,,0000,0000,0000,,you'll precisely end up with 0.2 molar
Dialogue: 0,0:01:06.20,0:01:09.12,Default,,0000,0000,0000,,concentration solution,\Nhow do you figure this out?
Dialogue: 0,0:01:09.12,0:01:10.38,Default,,0000,0000,0000,,And by the way, if you're wondering
Dialogue: 0,0:01:10.38,0:01:13.59,Default,,0000,0000,0000,,why do we have so many zeroes\Nand decimals over here?
Dialogue: 0,0:01:13.59,0:01:15.39,Default,,0000,0000,0000,,Well that's because we\Nhave precisely measured
Dialogue: 0,0:01:15.39,0:01:17.16,Default,,0000,0000,0000,,this to three significant figures.
Dialogue: 0,0:01:17.16,0:01:20.60,Default,,0000,0000,0000,,I mean, we take our Kool-Aid\Nvery seriously, okay?
Dialogue: 0,0:01:20.60,0:01:21.43,Default,,0000,0000,0000,,(Presenter laughing)
Dialogue: 0,0:01:21.43,0:01:23.36,Default,,0000,0000,0000,,But again, how do you figure this out?
Dialogue: 0,0:01:23.36,0:01:24.81,Default,,0000,0000,0000,,How do you figure out how much
Dialogue: 0,0:01:24.81,0:01:26.16,Default,,0000,0000,0000,,of the concentrated syrup do we need?
Dialogue: 0,0:01:26.16,0:01:27.12,Default,,0000,0000,0000,,How do you do this?
Dialogue: 0,0:01:27.12,0:01:28.68,Default,,0000,0000,0000,,Well, here's the key idea.
Dialogue: 0,0:01:28.68,0:01:30.60,Default,,0000,0000,0000,,If you look at this concentrated syrup
Dialogue: 0,0:01:30.60,0:01:32.13,Default,,0000,0000,0000,,that you have poured in a jug,
Dialogue: 0,0:01:32.13,0:01:35.57,Default,,0000,0000,0000,,it contains some moles of sugar.
Dialogue: 0,0:01:35.57,0:01:38.97,Default,,0000,0000,0000,,Now, when you add water to it,
Dialogue: 0,0:01:38.97,0:01:40.41,Default,,0000,0000,0000,,the amount of sugar,
Dialogue: 0,0:01:40.41,0:01:43.58,Default,,0000,0000,0000,,the amount of solute that\Nyou have doesn't change.
Dialogue: 0,0:01:43.58,0:01:48.36,Default,,0000,0000,0000,,Even this dilute solution\Nhas the same amount of sugar,
Dialogue: 0,0:01:48.36,0:01:50.94,Default,,0000,0000,0000,,but because now the volume of water,
Dialogue: 0,0:01:50.94,0:01:52.44,Default,,0000,0000,0000,,the solvent has increased,
Dialogue: 0,0:01:52.44,0:01:54.24,Default,,0000,0000,0000,,that's why it has become more dilute.
Dialogue: 0,0:01:54.24,0:01:55.07,Default,,0000,0000,0000,,So the key idea is,
Dialogue: 0,0:01:55.07,0:01:57.21,Default,,0000,0000,0000,,when you're diluting the amount of solute,
Dialogue: 0,0:01:57.21,0:02:00.90,Default,,0000,0000,0000,,which is sugar over here,\Nthat stays the same.
Dialogue: 0,0:02:00.90,0:02:02.43,Default,,0000,0000,0000,,And so let's write that down.
Dialogue: 0,0:02:02.43,0:02:05.04,Default,,0000,0000,0000,,I write this way, so this\Nrepresents the moles of sugar
Dialogue: 0,0:02:05.04,0:02:06.93,Default,,0000,0000,0000,,in the concentrated solution over here
Dialogue: 0,0:02:06.93,0:02:08.64,Default,,0000,0000,0000,,and this represent the moles of sugar
Dialogue: 0,0:02:08.64,0:02:10.47,Default,,0000,0000,0000,,in this dilute solution over here.
Dialogue: 0,0:02:10.47,0:02:12.72,Default,,0000,0000,0000,,But it has to be equal\Nbecause after adding water,
Dialogue: 0,0:02:12.72,0:02:14.61,Default,,0000,0000,0000,,the amount does not change.
Dialogue: 0,0:02:14.61,0:02:15.84,Default,,0000,0000,0000,,Well next I'm thinking,
Dialogue: 0,0:02:15.84,0:02:18.03,Default,,0000,0000,0000,,how do I figure out moles
Dialogue: 0,0:02:18.03,0:02:20.76,Default,,0000,0000,0000,,if I know the molarity and the volume?
Dialogue: 0,0:02:20.76,0:02:23.31,Default,,0000,0000,0000,,What's the connection between\Nmoles, molarity, and volume?
Dialogue: 0,0:02:23.31,0:02:24.81,Default,,0000,0000,0000,,Hey, we know that!
Dialogue: 0,0:02:24.81,0:02:29.40,Default,,0000,0000,0000,,Molarity is the amount\Nof moles per volume.
Dialogue: 0,0:02:29.40,0:02:32.04,Default,,0000,0000,0000,,So from this, I can rearrange\Nand find out what moles is.
Dialogue: 0,0:02:32.04,0:02:33.75,Default,,0000,0000,0000,,So I can rearrange this for moles,
Dialogue: 0,0:02:33.75,0:02:38.58,Default,,0000,0000,0000,,so I'll get moles equals\Nmolarity times volume.
Dialogue: 0,0:02:38.58,0:02:40.56,Default,,0000,0000,0000,,So I can plug in over here
Dialogue: 0,0:02:40.56,0:02:43.77,Default,,0000,0000,0000,,the molarity times\Nvolume for this solution
Dialogue: 0,0:02:43.77,0:02:45.24,Default,,0000,0000,0000,,and over here,
Dialogue: 0,0:02:45.24,0:02:47.79,Default,,0000,0000,0000,,molarity times volume\Nfor the dilute solution,
Dialogue: 0,0:02:47.79,0:02:50.13,Default,,0000,0000,0000,,equate it and I can figure out what V is.
Dialogue: 0,0:02:50.13,0:02:51.45,Default,,0000,0000,0000,,So feel free to pause the video
Dialogue: 0,0:02:51.45,0:02:53.69,Default,,0000,0000,0000,,and try it out yourself first.
Dialogue: 0,0:02:53.69,0:02:55.29,Default,,0000,0000,0000,,Alright, here we go.
Dialogue: 0,0:02:55.29,0:02:56.67,Default,,0000,0000,0000,,So the amount of moles over here
Dialogue: 0,0:02:56.67,0:03:00.12,Default,,0000,0000,0000,,would be the molarity over\Nhere, the molarity is four,
Dialogue: 0,0:03:00.12,0:03:05.12,Default,,0000,0000,0000,,so 4.00 molar times the\Nvolume, which I don't know,
Dialogue: 0,0:03:06.81,0:03:08.46,Default,,0000,0000,0000,,that's what I need to\Nfigure out, the volume
Dialogue: 0,0:03:08.46,0:03:11.91,Default,,0000,0000,0000,,of this concentrated\Nsolution, concentrated syrup.
Dialogue: 0,0:03:11.91,0:03:14.28,Default,,0000,0000,0000,,But that should equal the\Nmolarity times volume here,
Dialogue: 0,0:03:14.28,0:03:19.28,Default,,0000,0000,0000,,the molarity is 0.200 and\Nthe volume is five liters.
Dialogue: 0,0:03:22.92,0:03:23.79,Default,,0000,0000,0000,,So let's simplify this.
Dialogue: 0,0:03:23.79,0:03:25.47,Default,,0000,0000,0000,,The moles cancels out over here.
Dialogue: 0,0:03:25.47,0:03:28.47,Default,,0000,0000,0000,,On the right hand side, I\Nhave five multiplied by 0.2.
Dialogue: 0,0:03:28.47,0:03:30.87,Default,,0000,0000,0000,,Five times 0.2 is one
Dialogue: 0,0:03:30.87,0:03:32.64,Default,,0000,0000,0000,,and then if I divide\Nby four on both sides,
Dialogue: 0,0:03:32.64,0:03:33.78,Default,,0000,0000,0000,,I'll get one over four.
Dialogue: 0,0:03:33.78,0:03:38.78,Default,,0000,0000,0000,,So I get V equals one\Nliter divide by four,
Dialogue: 0,0:03:40.36,0:03:42.48,Default,,0000,0000,0000,,which equals 0.25.
Dialogue: 0,0:03:45.84,0:03:48.51,Default,,0000,0000,0000,,And I'm gonna put one more zero over here,
Dialogue: 0,0:03:48.51,0:03:52.56,Default,,0000,0000,0000,,because we have three\Nsignificant figures over here.
Dialogue: 0,0:03:52.56,0:03:55.95,Default,,0000,0000,0000,,So 0.250 liters,
Dialogue: 0,0:03:55.95,0:03:58.59,Default,,0000,0000,0000,,that's the volume of the\Nconcentrated solution
Dialogue: 0,0:03:58.59,0:04:01.02,Default,,0000,0000,0000,,that I should take, and the\Nrest, I should add water
Dialogue: 0,0:04:01.02,0:04:02.07,Default,,0000,0000,0000,,to fill it up to five liters
Dialogue: 0,0:04:02.07,0:04:06.12,Default,,0000,0000,0000,,and then I'll get 0.2\Nmolar solution that I want.
Dialogue: 0,0:04:06.12,0:04:08.25,Default,,0000,0000,0000,,Now, actually, we can generalize this.
Dialogue: 0,0:04:08.25,0:04:09.78,Default,,0000,0000,0000,,So if the concentration
Dialogue: 0,0:04:09.78,0:04:12.81,Default,,0000,0000,0000,,of the concentrate syrup was, say, M1
Dialogue: 0,0:04:12.81,0:04:15.57,Default,,0000,0000,0000,,and the volume of that syrup was V1,
Dialogue: 0,0:04:15.57,0:04:18.17,Default,,0000,0000,0000,,and let's say the dilute syrup\Nhad a concentration of M2,
Dialogue: 0,0:04:18.17,0:04:22.83,Default,,0000,0000,0000,,molarity was M2 and V2 was the\Namount of volume we needed,
Dialogue: 0,0:04:22.83,0:04:25.65,Default,,0000,0000,0000,,then after equating the moles,\Nwhat would we have gotten?
Dialogue: 0,0:04:25.65,0:04:30.65,Default,,0000,0000,0000,,We would've gotten M1 V1 equals M2 V2.
Dialogue: 0,0:04:31.17,0:04:33.12,Default,,0000,0000,0000,,And you can think of that
Dialogue: 0,0:04:33.12,0:04:35.55,Default,,0000,0000,0000,,as an equation that you\Ncan use for dilution.
Dialogue: 0,0:04:35.55,0:04:37.98,Default,,0000,0000,0000,,So we can write that down\Nas our dilution equation,
Dialogue: 0,0:04:37.98,0:04:39.81,Default,,0000,0000,0000,,which means whenever we're\Nsolving for such problems,
Dialogue: 0,0:04:39.81,0:04:43.20,Default,,0000,0000,0000,,all we have to do is equate the product
Dialogue: 0,0:04:43.20,0:04:44.43,Default,,0000,0000,0000,,of molarity and volume.
Dialogue: 0,0:04:44.43,0:04:46.47,Default,,0000,0000,0000,,The product of molarity and\Nvolume will stay the same
Dialogue: 0,0:04:46.47,0:04:47.58,Default,,0000,0000,0000,,even after dilution.
Dialogue: 0,0:04:47.58,0:04:48.54,Default,,0000,0000,0000,,What's the logic behind it?
Dialogue: 0,0:04:48.54,0:04:49.77,Default,,0000,0000,0000,,Why does that product stay the same?
Dialogue: 0,0:04:49.77,0:04:50.60,Default,,0000,0000,0000,,Well, because look,
Dialogue: 0,0:04:50.60,0:04:53.43,Default,,0000,0000,0000,,the product represents\Nthe moles of salute.
Dialogue: 0,0:04:53.43,0:04:56.19,Default,,0000,0000,0000,,Here, the salute is sugar,\Nbut it'll work for any salute,
Dialogue: 0,0:04:56.19,0:04:58.05,Default,,0000,0000,0000,,any dilution case, this will work.
Dialogue: 0,0:04:58.05,0:04:59.61,Default,,0000,0000,0000,,The whole point is when you dilute it,
Dialogue: 0,0:04:59.61,0:05:02.16,Default,,0000,0000,0000,,the salute and the amount\Nof salute does not change,
Dialogue: 0,0:05:02.16,0:05:03.81,Default,,0000,0000,0000,,so the moles of salute stay the same
Dialogue: 0,0:05:03.81,0:05:05.67,Default,,0000,0000,0000,,and that's why the product stays the same
Dialogue: 0,0:05:05.67,0:05:08.70,Default,,0000,0000,0000,,and we can now use this dilution equation
Dialogue: 0,0:05:08.70,0:05:09.96,Default,,0000,0000,0000,,to try and solve the problem.
Dialogue: 0,0:05:09.96,0:05:12.78,Default,,0000,0000,0000,,So let's try and solve\Nanother problem here.
Dialogue: 0,0:05:12.78,0:05:16.20,Default,,0000,0000,0000,,How much of 12 molar H2SO4 sulfuric acid,
Dialogue: 0,0:05:16.20,0:05:21.20,Default,,0000,0000,0000,,do we need to create a 0.5\Nliter of three molar acid?
Dialogue: 0,0:05:21.54,0:05:24.69,Default,,0000,0000,0000,,So we have a 12 molar\NH2SO4 solution with us,
Dialogue: 0,0:05:24.69,0:05:27.24,Default,,0000,0000,0000,,that's the stock solution\Nthat we usually find in labs,
Dialogue: 0,0:05:27.24,0:05:28.47,Default,,0000,0000,0000,,it's very concentrated.
Dialogue: 0,0:05:28.47,0:05:32.25,Default,,0000,0000,0000,,So that's the concentrate\Nsolution that we have.
Dialogue: 0,0:05:32.25,0:05:34.23,Default,,0000,0000,0000,,Now what we need to do is create
Dialogue: 0,0:05:34.23,0:05:36.21,Default,,0000,0000,0000,,a much more dilute\Nsolution, as you can see.
Dialogue: 0,0:05:36.21,0:05:41.21,Default,,0000,0000,0000,,So we want to create 0.5\Nliters of three molar.
Dialogue: 0,0:05:42.15,0:05:43.83,Default,,0000,0000,0000,,So you can see it's very dilute.
Dialogue: 0,0:05:43.83,0:05:46.05,Default,,0000,0000,0000,,We need to create a\Ndilute solution of H2SO4
Dialogue: 0,0:05:46.05,0:05:47.91,Default,,0000,0000,0000,,and just like before, we're\Ngonna take a little bit of this
Dialogue: 0,0:05:47.91,0:05:50.91,Default,,0000,0000,0000,,and add it to a lot of water\Nto create our dilute solution.
Dialogue: 0,0:05:50.91,0:05:51.87,Default,,0000,0000,0000,,And the question is,
Dialogue: 0,0:05:51.87,0:05:54.72,Default,,0000,0000,0000,,how much of the concentrated\Nstuff do we need?
Dialogue: 0,0:05:54.72,0:05:56.37,Default,,0000,0000,0000,,So how do we solve it?
Dialogue: 0,0:05:56.37,0:05:57.80,Default,,0000,0000,0000,,Well, we have our dilution equation,
Dialogue: 0,0:05:57.80,0:05:59.94,Default,,0000,0000,0000,,so let's see what's given to us.
Dialogue: 0,0:05:59.94,0:06:01.02,Default,,0000,0000,0000,,Well, we have the molarity
Dialogue: 0,0:06:01.02,0:06:03.90,Default,,0000,0000,0000,,of the concentrate H2HSO4,\Nwe can call this M1,
Dialogue: 0,0:06:03.90,0:06:05.82,Default,,0000,0000,0000,,so we know M1, what about V1?
Dialogue: 0,0:06:05.82,0:06:08.91,Default,,0000,0000,0000,,V1 would be then the volume\Nof the concentered H2SO4,
Dialogue: 0,0:06:08.91,0:06:10.08,Default,,0000,0000,0000,,hey, that's what we don't have,
Dialogue: 0,0:06:10.08,0:06:11.46,Default,,0000,0000,0000,,that's what we need to figure out.
Dialogue: 0,0:06:11.46,0:06:14.31,Default,,0000,0000,0000,,Then M2 would now be the volume,
Dialogue: 0,0:06:14.31,0:06:16.41,Default,,0000,0000,0000,,the molarity of the dilute\Nsolution that's given to us
Dialogue: 0,0:06:16.41,0:06:18.39,Default,,0000,0000,0000,,and V2 would be the volume\Nof the dilute solution
Dialogue: 0,0:06:18.39,0:06:19.71,Default,,0000,0000,0000,,that's given to us as well.
Dialogue: 0,0:06:19.71,0:06:21.96,Default,,0000,0000,0000,,So we're given M1, we are\Ngiven M2, we are given V2,
Dialogue: 0,0:06:21.96,0:06:23.19,Default,,0000,0000,0000,,we need to figure out V1.
Dialogue: 0,0:06:23.19,0:06:25.20,Default,,0000,0000,0000,,We just plug in over here and do that.
Dialogue: 0,0:06:25.20,0:06:26.91,Default,,0000,0000,0000,,So let's do that, feel\Nfree to pause the video
Dialogue: 0,0:06:26.91,0:06:29.22,Default,,0000,0000,0000,,and try it on your own\Nfirst, we can do that now.
Dialogue: 0,0:06:29.22,0:06:34.22,Default,,0000,0000,0000,,So M1, V1 equals M2, so that's 3.00
Dialogue: 0,0:06:38.76,0:06:42.75,Default,,0000,0000,0000,,times V2 that's 0.500.
Dialogue: 0,0:06:42.75,0:06:45.93,Default,,0000,0000,0000,,And we can simplify, so the\Nmolar cancels out over here
Dialogue: 0,0:06:45.93,0:06:47.67,Default,,0000,0000,0000,,and so how much is our V1?
Dialogue: 0,0:06:47.67,0:06:51.63,Default,,0000,0000,0000,,Well, three times 0.5 is 1.5,
Dialogue: 0,0:06:51.63,0:06:53.22,Default,,0000,0000,0000,,and then I divide by 12 on both sides,
Dialogue: 0,0:06:53.22,0:06:58.22,Default,,0000,0000,0000,,so V1 equals 1.5, let\Nme use the same color,
Dialogue: 0,0:06:58.29,0:07:03.29,Default,,0000,0000,0000,,1.500 liters divided by 12, 12.0,
Dialogue: 0,0:07:05.03,0:07:09.95,Default,,0000,0000,0000,,and that gives me 1.5, divided by 12.125
Dialogue: 0,0:07:12.12,0:07:15.06,Default,,0000,0000,0000,,and I have to write it down\Nto three significant figures,
Dialogue: 0,0:07:15.06,0:07:16.91,Default,,0000,0000,0000,,so that's going to be 0.125.
Dialogue: 0,0:07:19.05,0:07:20.55,Default,,0000,0000,0000,,So three significant figures,
Dialogue: 0,0:07:20.55,0:07:23.61,Default,,0000,0000,0000,,liters, that's the unit that\Nwe have and there we have it.
Dialogue: 0,0:07:23.61,0:07:25.23,Default,,0000,0000,0000,,So this is the amount\Nof concentrated stuff
Dialogue: 0,0:07:25.23,0:07:28.53,Default,,0000,0000,0000,,that we need to add to water\Nto get our desired solution.
Dialogue: 0,0:07:28.53,0:07:30.51,Default,,0000,0000,0000,,So how exactly would we carry it out?
Dialogue: 0,0:07:30.51,0:07:34.98,Default,,0000,0000,0000,,Well, we'll first extract\N0.125 liters of this
Dialogue: 0,0:07:34.98,0:07:39.03,Default,,0000,0000,0000,,in a pipet or usually in a\Ngraduated cylinder like this.
Dialogue: 0,0:07:39.03,0:07:40.86,Default,,0000,0000,0000,,Then we'll take the\Nrequired amount of water
Dialogue: 0,0:07:40.86,0:07:42.81,Default,,0000,0000,0000,,in a separate flask, say a clinical flask,
Dialogue: 0,0:07:42.81,0:07:44.55,Default,,0000,0000,0000,,but how do I know how\Nmuch water do I need?
Dialogue: 0,0:07:44.55,0:07:46.11,Default,,0000,0000,0000,,We'll, think about, this is how much,
Dialogue: 0,0:07:46.11,0:07:48.00,Default,,0000,0000,0000,,this is the final volume I need,
Dialogue: 0,0:07:48.00,0:07:51.66,Default,,0000,0000,0000,,in this, this is the amount of acid,
Dialogue: 0,0:07:51.66,0:07:54.63,Default,,0000,0000,0000,,so the remaining must be water.
Dialogue: 0,0:07:54.63,0:07:58.35,Default,,0000,0000,0000,,So the amount of water\Nmust be this minus this,
Dialogue: 0,0:07:58.35,0:07:59.67,Default,,0000,0000,0000,,so we do minus V1,
Dialogue: 0,0:07:59.67,0:08:01.71,Default,,0000,0000,0000,,so this is the exact\Namount of water I need.
Dialogue: 0,0:08:01.71,0:08:04.23,Default,,0000,0000,0000,,So I'm gonna take that\Nin the clinical flask
Dialogue: 0,0:08:04.23,0:08:06.99,Default,,0000,0000,0000,,and then never add water to the acid,
Dialogue: 0,0:08:06.99,0:08:08.43,Default,,0000,0000,0000,,that can be very dangerous
Dialogue: 0,0:08:08.43,0:08:09.60,Default,,0000,0000,0000,,because this is concentrated stuff.
Dialogue: 0,0:08:09.60,0:08:11.79,Default,,0000,0000,0000,,The water over here can\Njust boil and splash
Dialogue: 0,0:08:11.79,0:08:12.84,Default,,0000,0000,0000,,and in fact, that's one of the reasons
Dialogue: 0,0:08:12.84,0:08:14.19,Default,,0000,0000,0000,,you should always have your safety,
Dialogue: 0,0:08:14.19,0:08:15.63,Default,,0000,0000,0000,,you should have your safety goggles,
Dialogue: 0,0:08:15.63,0:08:17.58,Default,,0000,0000,0000,,your lab coat and all of that stuff.
Dialogue: 0,0:08:17.58,0:08:20.67,Default,,0000,0000,0000,,But anyways, never add water\Nto the acid to dilute it out,
Dialogue: 0,0:08:20.67,0:08:22.02,Default,,0000,0000,0000,,it's the always the other way around,
Dialogue: 0,0:08:22.02,0:08:25.56,Default,,0000,0000,0000,,you add this acid to the water, slowly,
Dialogue: 0,0:08:25.56,0:08:26.76,Default,,0000,0000,0000,,and you keep mixing it
Dialogue: 0,0:08:26.76,0:08:31.76,Default,,0000,0000,0000,,and finally, that's how you're\Ngonna prepare your solution.
Dialogue: 0,0:08:32.06,0:08:35.01,Default,,0000,0000,0000,,All right, let's try another problem.
Dialogue: 0,0:08:35.01,0:08:38.31,Default,,0000,0000,0000,,What volume of three molar HCL can be made
Dialogue: 0,0:08:38.31,0:08:42.90,Default,,0000,0000,0000,,if we only have 10 ml of 12 molar HCL,
Dialogue: 0,0:08:42.90,0:08:43.83,Default,,0000,0000,0000,,Why don't you pause the video
Dialogue: 0,0:08:43.83,0:08:45.36,Default,,0000,0000,0000,,and see if we can solve this problem
Dialogue: 0,0:08:45.36,0:08:47.22,Default,,0000,0000,0000,,using the dilution equation?
Dialogue: 0,0:08:48.27,0:08:49.17,Default,,0000,0000,0000,,Alright, let's see.
Dialogue: 0,0:08:49.17,0:08:52.59,Default,,0000,0000,0000,,So we have 10 ml of 12 molar HCL,
Dialogue: 0,0:08:52.59,0:08:55.95,Default,,0000,0000,0000,,that's what we have right\Nnow and we to convert it
Dialogue: 0,0:08:55.95,0:08:59.01,Default,,0000,0000,0000,,into a much more dilute\Nthree molar HCL solution,
Dialogue: 0,0:08:59.01,0:09:00.96,Default,,0000,0000,0000,,which means we are\Ngoing to add water to it
Dialogue: 0,0:09:00.96,0:09:02.76,Default,,0000,0000,0000,,and if we're going to increase its volume,
Dialogue: 0,0:09:02.76,0:09:04.89,Default,,0000,0000,0000,,the big question is what\Nwould that volume be
Dialogue: 0,0:09:04.89,0:09:07.83,Default,,0000,0000,0000,,in order for it to become three molar HCL?
Dialogue: 0,0:09:07.83,0:09:09.09,Default,,0000,0000,0000,,So this is the concentrated stuff,
Dialogue: 0,0:09:09.09,0:09:10.17,Default,,0000,0000,0000,,so let me color code that.
Dialogue: 0,0:09:10.17,0:09:12.18,Default,,0000,0000,0000,,So this is our...
Dialogue: 0,0:09:12.18,0:09:14.34,Default,,0000,0000,0000,,I'm gonna use dark red\Nfor the concentrated one,
Dialogue: 0,0:09:14.34,0:09:15.71,Default,,0000,0000,0000,,so this is our concentrated stuff
Dialogue: 0,0:09:15.71,0:09:18.30,Default,,0000,0000,0000,,and we are going to convert it
Dialogue: 0,0:09:18.30,0:09:20.52,Default,,0000,0000,0000,,into a much more dilute stuff
Dialogue: 0,0:09:20.52,0:09:24.18,Default,,0000,0000,0000,,and the question is,\Nwhat's the volume for that?
Dialogue: 0,0:09:24.18,0:09:27.06,Default,,0000,0000,0000,,So we can now write down what\Nour M1, V1 and M2, V2 are.
Dialogue: 0,0:09:27.06,0:09:32.05,Default,,0000,0000,0000,,So we can say this is our\NM1 and this would be our V1,
Dialogue: 0,0:09:32.05,0:09:34.83,Default,,0000,0000,0000,,then this would be our M2,
Dialogue: 0,0:09:34.83,0:09:36.81,Default,,0000,0000,0000,,and then we have to figure out what V2 is.
Dialogue: 0,0:09:36.81,0:09:38.22,Default,,0000,0000,0000,,I mean, of course
Dialogue: 0,0:09:38.22,0:09:40.33,Default,,0000,0000,0000,,you can call anything\None and anything two.
Dialogue: 0,0:09:40.33,0:09:42.03,Default,,0000,0000,0000,,But now that we have this
Dialogue: 0,0:09:42.03,0:09:43.83,Default,,0000,0000,0000,,or we can just plug into this equation
Dialogue: 0,0:09:43.83,0:09:45.69,Default,,0000,0000,0000,,and figure out what V2 is going to be.
Dialogue: 0,0:09:45.69,0:09:48.41,Default,,0000,0000,0000,,So if we do that, we'll get M1, V1,
Dialogue: 0,0:09:48.41,0:09:51.48,Default,,0000,0000,0000,,12 times 10 should equal three times V2.
Dialogue: 0,0:09:53.29,0:09:54.21,Default,,0000,0000,0000,,And now we can just simplify this,
Dialogue: 0,0:09:54.21,0:09:56.67,Default,,0000,0000,0000,,so this molar cancels out over here
Dialogue: 0,0:09:56.67,0:09:58.26,Default,,0000,0000,0000,,and I'll be left with milliliters,
Dialogue: 0,0:09:58.26,0:09:59.45,Default,,0000,0000,0000,,do I need to convert this milliliter?
Dialogue: 0,0:09:59.45,0:10:00.78,Default,,0000,0000,0000,,I mean, in this particular case,
Dialogue: 0,0:10:00.78,0:10:02.83,Default,,0000,0000,0000,,you don't have to because\Nthis is the only unit,
Dialogue: 0,0:10:02.83,0:10:05.73,Default,,0000,0000,0000,,our V2 answer will be\Nin terms of milliliters,
Dialogue: 0,0:10:05.73,0:10:07.10,Default,,0000,0000,0000,,we can just keep it that way.
Dialogue: 0,0:10:07.10,0:10:08.19,Default,,0000,0000,0000,,So what will I get?,
Dialogue: 0,0:10:08.19,0:10:10.77,Default,,0000,0000,0000,,I get divide by three on both sides,
Dialogue: 0,0:10:10.77,0:10:12.06,Default,,0000,0000,0000,,so twelve by three would be four,
Dialogue: 0,0:10:12.06,0:10:13.80,Default,,0000,0000,0000,,four times ten would be 40.
Dialogue: 0,0:10:13.80,0:10:18.18,Default,,0000,0000,0000,,So I would actually end up with 40
Dialogue: 0,0:10:18.18,0:10:20.94,Default,,0000,0000,0000,,and I have to put three\Nsignificant figures,
Dialogue: 0,0:10:20.94,0:10:25.94,Default,,0000,0000,0000,,so it's gonna be 40.0\Nml, that will be our V2.
Dialogue: 0,0:10:26.79,0:10:29.46,Default,,0000,0000,0000,,So this means I can make 40 ml
Dialogue: 0,0:10:29.46,0:10:32.19,Default,,0000,0000,0000,,of the dilute three molar HCL solution
Dialogue: 0,0:10:32.19,0:10:34.02,Default,,0000,0000,0000,,from this concentrate stuff.