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Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.18,0:00:01.77,Default,,0000,0000,0000,,- [Instructor] I used to\Nalways think of solutions
Dialogue: 0,0:00:01.77,0:00:04.08,Default,,0000,0000,0000,,as liquids of some kind,
Dialogue: 0,0:00:04.08,0:00:05.76,Default,,0000,0000,0000,,but turns out that it's wrong.
Dialogue: 0,0:00:05.76,0:00:07.68,Default,,0000,0000,0000,,Not all liquids are solutions.
Dialogue: 0,0:00:07.68,0:00:10.35,Default,,0000,0000,0000,,And more importantly,\Nsolutions can be solids,
Dialogue: 0,0:00:10.35,0:00:12.15,Default,,0000,0000,0000,,liquids, or gases.
Dialogue: 0,0:00:12.15,0:00:12.99,Default,,0000,0000,0000,,So, in this video,
Dialogue: 0,0:00:12.99,0:00:15.15,Default,,0000,0000,0000,,let's understand exactly\Nwhat solutions are.
Dialogue: 0,0:00:15.15,0:00:16.86,Default,,0000,0000,0000,,So, let's take a concrete example.
Dialogue: 0,0:00:16.86,0:00:19.83,Default,,0000,0000,0000,,Let's put some salt in water\Nand stir it very nicely.
Dialogue: 0,0:00:19.83,0:00:24.33,Default,,0000,0000,0000,,We get salt water, but\Nwhat exactly is salt water?
Dialogue: 0,0:00:24.33,0:00:25.41,Default,,0000,0000,0000,,Let's analyze.
Dialogue: 0,0:00:25.41,0:00:27.27,Default,,0000,0000,0000,,Do you think salt water is an element?
Dialogue: 0,0:00:27.27,0:00:30.06,Default,,0000,0000,0000,,Elements are made of\Njust one kind of atoms.
Dialogue: 0,0:00:30.06,0:00:31.83,Default,,0000,0000,0000,,For example, you have oxygen
Dialogue: 0,0:00:31.83,0:00:33.15,Default,,0000,0000,0000,,which is made of only oxygen atoms
Dialogue: 0,0:00:33.15,0:00:35.25,Default,,0000,0000,0000,,or gold made of only gold atoms.
Dialogue: 0,0:00:35.25,0:00:38.07,Default,,0000,0000,0000,,Well, salt water has different\Nkinds of atoms in them.
Dialogue: 0,0:00:38.07,0:00:40.35,Default,,0000,0000,0000,,There's water, therefore\Nthere's hydrogen and oxygen,
Dialogue: 0,0:00:40.35,0:00:41.55,Default,,0000,0000,0000,,and we also put salt.
Dialogue: 0,0:00:41.55,0:00:43.77,Default,,0000,0000,0000,,So, there's sodium and\Nthere's also chlorine.
Dialogue: 0,0:00:43.77,0:00:47.61,Default,,0000,0000,0000,,So, since salt water is made\Nof several different elements,
Dialogue: 0,0:00:47.61,0:00:49.68,Default,,0000,0000,0000,,it is not an element.
Dialogue: 0,0:00:49.68,0:00:50.91,Default,,0000,0000,0000,,What else could it be?
Dialogue: 0,0:00:50.91,0:00:53.13,Default,,0000,0000,0000,,Hey, what about compounds?
Dialogue: 0,0:00:53.13,0:00:54.21,Default,,0000,0000,0000,,Remember in compounds,
Dialogue: 0,0:00:54.21,0:00:57.54,Default,,0000,0000,0000,,two or more atoms are chemically\Nbonded in fixed ratios.
Dialogue: 0,0:00:57.54,0:00:59.19,Default,,0000,0000,0000,,For example, water is a compound
Dialogue: 0,0:00:59.19,0:01:01.83,Default,,0000,0000,0000,,because hydrogen and oxygen\Nare chemically bonded
Dialogue: 0,0:01:01.83,0:01:05.31,Default,,0000,0000,0000,,in the ratio two is to one,\Ntwo hydrogen for every oxygen.
Dialogue: 0,0:01:05.31,0:01:06.63,Default,,0000,0000,0000,,Carbon dioxide is a compound,
Dialogue: 0,0:01:06.63,0:01:08.73,Default,,0000,0000,0000,,because carbon and oxygen\Nare chemically bonded
Dialogue: 0,0:01:08.73,0:01:10.83,Default,,0000,0000,0000,,in the ratio one is to two,
Dialogue: 0,0:01:10.83,0:01:13.08,Default,,0000,0000,0000,,one carbon for every two oxygens.
Dialogue: 0,0:01:13.08,0:01:14.94,Default,,0000,0000,0000,,So, what about salt water?
Dialogue: 0,0:01:14.94,0:01:16.44,Default,,0000,0000,0000,,Is that a compound?
Dialogue: 0,0:01:16.44,0:01:18.57,Default,,0000,0000,0000,,No, it's not, and this is important,
Dialogue: 0,0:01:18.57,0:01:21.78,Default,,0000,0000,0000,,because salt and water\Nare not chemically bonded,
Dialogue: 0,0:01:21.78,0:01:24.18,Default,,0000,0000,0000,,they are physically mixed over here,
Dialogue: 0,0:01:24.18,0:01:25.80,Default,,0000,0000,0000,,and they don't have a fixed ratio.
Dialogue: 0,0:01:25.80,0:01:27.96,Default,,0000,0000,0000,,You can have different ratios\Nof salt and water here.
Dialogue: 0,0:01:27.96,0:01:29.79,Default,,0000,0000,0000,,Now, of course, salt is a compound,
Dialogue: 0,0:01:29.79,0:01:32.55,Default,,0000,0000,0000,,because sodium and chlorine\Nare chemically bonded in.
Dialogue: 0,0:01:32.55,0:01:35.55,Default,,0000,0000,0000,,One is to one fixed ratio,\Nand water is a compound.
Dialogue: 0,0:01:35.55,0:01:36.96,Default,,0000,0000,0000,,But salt water?
Dialogue: 0,0:01:36.96,0:01:38.31,Default,,0000,0000,0000,,That's not a compound at all.
Dialogue: 0,0:01:38.31,0:01:40.74,Default,,0000,0000,0000,,And more importantly,\Ncompounds are new substances
Dialogue: 0,0:01:40.74,0:01:42.42,Default,,0000,0000,0000,,with different properties altogether.
Dialogue: 0,0:01:42.42,0:01:44.61,Default,,0000,0000,0000,,When hydrogen and oxygen form a compound,
Dialogue: 0,0:01:44.61,0:01:46.17,Default,,0000,0000,0000,,you get water, which is a new substance.
Dialogue: 0,0:01:46.17,0:01:48.27,Default,,0000,0000,0000,,It has its own properties,\Nit has its own taste,
Dialogue: 0,0:01:48.27,0:01:50.01,Default,,0000,0000,0000,,it has its own boiling point.
Dialogue: 0,0:01:50.01,0:01:51.72,Default,,0000,0000,0000,,Similarly, sodium and\Nchlorine coming together,
Dialogue: 0,0:01:51.72,0:01:54.18,Default,,0000,0000,0000,,you get salt, which is a\Nnew substance altogether.
Dialogue: 0,0:01:54.18,0:01:55.68,Default,,0000,0000,0000,,It has its own taste,
Dialogue: 0,0:01:55.68,0:01:58.35,Default,,0000,0000,0000,,it has its own melting\Npoint, boiling point.
Dialogue: 0,0:01:58.35,0:02:00.21,Default,,0000,0000,0000,,But when you dissolve salt in water,
Dialogue: 0,0:02:00.21,0:02:01.98,Default,,0000,0000,0000,,you don't get a new substance.
Dialogue: 0,0:02:01.98,0:02:04.05,Default,,0000,0000,0000,,You basically get salt water,
Dialogue: 0,0:02:04.05,0:02:06.21,Default,,0000,0000,0000,,and you don't have new properties.
Dialogue: 0,0:02:06.21,0:02:08.82,Default,,0000,0000,0000,,It's still salty, it's still watery.
Dialogue: 0,0:02:08.82,0:02:11.07,Default,,0000,0000,0000,,And finally, remember, the\Natoms of that compounds
Dialogue: 0,0:02:11.07,0:02:13.29,Default,,0000,0000,0000,,cannot be physically separated.
Dialogue: 0,0:02:13.29,0:02:15.24,Default,,0000,0000,0000,,For example, when you heat\Nwater to its boiling point,
Dialogue: 0,0:02:15.24,0:02:17.58,Default,,0000,0000,0000,,the hydrogen and oxygen\Natoms do not separate.
Dialogue: 0,0:02:17.58,0:02:19.92,Default,,0000,0000,0000,,The water molecule just move\Nfarther away from each other
Dialogue: 0,0:02:19.92,0:02:21.27,Default,,0000,0000,0000,,as it changes to gas.
Dialogue: 0,0:02:21.27,0:02:24.39,Default,,0000,0000,0000,,But here, salt and water\Ncan be physically separated,
Dialogue: 0,0:02:24.39,0:02:27.21,Default,,0000,0000,0000,,just evaporate the water,\Nsalt will be left behind.
Dialogue: 0,0:02:27.21,0:02:29.55,Default,,0000,0000,0000,,So, hopefully it's clear\Nthat this is not a compound.
Dialogue: 0,0:02:29.55,0:02:30.60,Default,,0000,0000,0000,,But what is this?
Dialogue: 0,0:02:30.60,0:02:32.31,Default,,0000,0000,0000,,Well, when you mix two\Nsubstances together,
Dialogue: 0,0:02:32.31,0:02:34.32,Default,,0000,0000,0000,,we get what is called a mixture.
Dialogue: 0,0:02:34.32,0:02:36.51,Default,,0000,0000,0000,,And since this mixture\Nis uniformed throughout,
Dialogue: 0,0:02:36.51,0:02:39.03,Default,,0000,0000,0000,,you cannot, with your\Nnaked eyes, see the salt
Dialogue: 0,0:02:39.03,0:02:41.04,Default,,0000,0000,0000,,and the water to be different over here.
Dialogue: 0,0:02:41.04,0:02:43.83,Default,,0000,0000,0000,,We call such mixtures homogenous mixtures.
Dialogue: 0,0:02:43.83,0:02:46.44,Default,,0000,0000,0000,,In contrast, mixtures in\Nwhich the different components
Dialogue: 0,0:02:46.44,0:02:49.26,Default,,0000,0000,0000,,can be easily seen, like\Nfor example, water and oil,
Dialogue: 0,0:02:49.26,0:02:50.82,Default,,0000,0000,0000,,you can clearly see oil over here,
Dialogue: 0,0:02:50.82,0:02:52.74,Default,,0000,0000,0000,,you can see water here,\Nyou can see the boundary.
Dialogue: 0,0:02:52.74,0:02:55.38,Default,,0000,0000,0000,,In such cases, we call them\Nheterogeneous mixtures.
Dialogue: 0,0:02:55.38,0:02:57.00,Default,,0000,0000,0000,,But anyways, in our example,
Dialogue: 0,0:02:57.00,0:02:58.68,Default,,0000,0000,0000,,salt water is a homogenous mixture.
Dialogue: 0,0:02:58.68,0:02:59.52,Default,,0000,0000,0000,,And guess what?
Dialogue: 0,0:02:59.52,0:03:03.48,Default,,0000,0000,0000,,These homogenous mixtures\Nare what we call solutions.
Dialogue: 0,0:03:03.48,0:03:06.39,Default,,0000,0000,0000,,So, let's look at solutions in\Na little bit more detail now.
Dialogue: 0,0:03:06.39,0:03:08.52,Default,,0000,0000,0000,,Solutions usually contain two things.
Dialogue: 0,0:03:08.52,0:03:11.49,Default,,0000,0000,0000,,We have the solute and the solvent.
Dialogue: 0,0:03:11.49,0:03:14.19,Default,,0000,0000,0000,,Here, you can think of solute\Nas something that is dissolved
Dialogue: 0,0:03:14.19,0:03:17.64,Default,,0000,0000,0000,,in the solvent to form a\Nsolution, but in general,
Dialogue: 0,0:03:17.64,0:03:19.20,Default,,0000,0000,0000,,you can think of solute as a substance
Dialogue: 0,0:03:19.20,0:03:20.43,Default,,0000,0000,0000,,which is in less quantity,
Dialogue: 0,0:03:20.43,0:03:23.19,Default,,0000,0000,0000,,and solvent is is the substance\Nthat is in more quantity.
Dialogue: 0,0:03:23.19,0:03:24.99,Default,,0000,0000,0000,,But now, let's look at more examples.
Dialogue: 0,0:03:24.99,0:03:26.16,Default,,0000,0000,0000,,What about air?
Dialogue: 0,0:03:26.16,0:03:29.28,Default,,0000,0000,0000,,Well, air is a homogenous\Nmixture of oxygen, nitrogen,
Dialogue: 0,0:03:29.28,0:03:31.23,Default,,0000,0000,0000,,carbon dioxide, and many other gases.
Dialogue: 0,0:03:31.23,0:03:32.94,Default,,0000,0000,0000,,So, air is a solution.
Dialogue: 0,0:03:32.94,0:03:35.49,Default,,0000,0000,0000,,So, look, solution need\Nnot be just liquids.
Dialogue: 0,0:03:35.49,0:03:37.29,Default,,0000,0000,0000,,Solutions can be gases.
Dialogue: 0,0:03:37.29,0:03:40.56,Default,,0000,0000,0000,,And then think about alloy,\Nwhich are made by mixing metals.
Dialogue: 0,0:03:40.56,0:03:43.47,Default,,0000,0000,0000,,Like, say, steel is made\Nby mixing iron and carbon,
Dialogue: 0,0:03:43.47,0:03:46.80,Default,,0000,0000,0000,,and bronze is made by\Nmixing copper and tin.
Dialogue: 0,0:03:46.80,0:03:48.63,Default,,0000,0000,0000,,These are also homogenous mixtures.
Dialogue: 0,0:03:48.63,0:03:50.64,Default,,0000,0000,0000,,The metals are mixed throughout uniformly.
Dialogue: 0,0:03:50.64,0:03:52.17,Default,,0000,0000,0000,,You cannot see them separately,
Dialogue: 0,0:03:52.17,0:03:54.42,Default,,0000,0000,0000,,and therefore these are also solutions.
Dialogue: 0,0:03:54.42,0:03:57.12,Default,,0000,0000,0000,,So you can see, solutions\Ncan also be solids.
Dialogue: 0,0:03:57.12,0:04:00.42,Default,,0000,0000,0000,,Now, a key thing about solutions\Nis their concentration.
Dialogue: 0,0:04:00.42,0:04:02.70,Default,,0000,0000,0000,,If you have a lot of solute, relatively,
Dialogue: 0,0:04:02.70,0:04:03.60,Default,,0000,0000,0000,,compared to the solvent,
Dialogue: 0,0:04:03.60,0:04:05.46,Default,,0000,0000,0000,,we say it's a very concentrated solution.
Dialogue: 0,0:04:05.46,0:04:07.62,Default,,0000,0000,0000,,And if you have less solute\Ncompared to the solvent,
Dialogue: 0,0:04:07.62,0:04:09.39,Default,,0000,0000,0000,,we say it is a dilute solution.
Dialogue: 0,0:04:09.39,0:04:11.43,Default,,0000,0000,0000,,But why should we care\Nabout the concentration?
Dialogue: 0,0:04:11.43,0:04:12.36,Default,,0000,0000,0000,,Well, here's the thing,
Dialogue: 0,0:04:12.36,0:04:14.13,Default,,0000,0000,0000,,although individual components will have
Dialogue: 0,0:04:14.13,0:04:16.41,Default,,0000,0000,0000,,their own separate properties\Nbecause it's a mixture,
Dialogue: 0,0:04:16.41,0:04:19.38,Default,,0000,0000,0000,,it turns out that the property\Nof the solution itself
Dialogue: 0,0:04:19.38,0:04:21.48,Default,,0000,0000,0000,,can vary, depend upon the concentration.
Dialogue: 0,0:04:21.48,0:04:23.64,Default,,0000,0000,0000,,For example, usually, water freezes
Dialogue: 0,0:04:23.64,0:04:25.65,Default,,0000,0000,0000,,at about zero degrees\NCelsius, but guess what?
Dialogue: 0,0:04:25.65,0:04:29.40,Default,,0000,0000,0000,,When you add salt to it, the\Nfreezing point of this solution
Dialogue: 0,0:04:29.40,0:04:31.71,Default,,0000,0000,0000,,is below zero degrees Celsius.
Dialogue: 0,0:04:31.71,0:04:34.44,Default,,0000,0000,0000,,Similarly, if there is\Nwater molecules in the air,
Dialogue: 0,0:04:34.44,0:04:35.91,Default,,0000,0000,0000,,we say there is humidity.
Dialogue: 0,0:04:35.91,0:04:38.97,Default,,0000,0000,0000,,A lot of water molecules means\Nthere is a lot of humidity.
Dialogue: 0,0:04:38.97,0:04:41.10,Default,,0000,0000,0000,,Humidity changes the\Nproperties of the air.
Dialogue: 0,0:04:41.10,0:04:42.78,Default,,0000,0000,0000,,For example, the speed of sound changes,
Dialogue: 0,0:04:42.78,0:04:44.85,Default,,0000,0000,0000,,its density changes, and so on.
Dialogue: 0,0:04:44.85,0:04:48.18,Default,,0000,0000,0000,,And similarly, steel is made\Nby adding carbon to iron.
Dialogue: 0,0:04:48.18,0:04:50.19,Default,,0000,0000,0000,,And by increasing the\Ncarbon concentration,
Dialogue: 0,0:04:50.19,0:04:51.90,Default,,0000,0000,0000,,we can make steel harder.
Dialogue: 0,0:04:51.90,0:04:54.15,Default,,0000,0000,0000,,We can make it stronger and more durable.
Dialogue: 0,0:04:54.15,0:04:56.88,Default,,0000,0000,0000,,So, look, by changing the\Nconcentrations of the solute,
Dialogue: 0,0:04:56.88,0:04:59.82,Default,,0000,0000,0000,,we can vary the properties\Nof the solution itself,
Dialogue: 0,0:04:59.82,0:05:01.47,Default,,0000,0000,0000,,and that is pretty awesome.
Dialogue: 0,0:05:01.47,0:05:02.97,Default,,0000,0000,0000,,So, putting it all together,
Dialogue: 0,0:05:02.97,0:05:04.83,Default,,0000,0000,0000,,matter can be classified into two parts.
Dialogue: 0,0:05:04.83,0:05:08.07,Default,,0000,0000,0000,,We have pure substances,\Nwhich are basically elements
Dialogue: 0,0:05:08.07,0:05:10.59,Default,,0000,0000,0000,,which are made of just one kind of atoms,
Dialogue: 0,0:05:10.59,0:05:12.30,Default,,0000,0000,0000,,or they can be compounds
Dialogue: 0,0:05:12.30,0:05:14.94,Default,,0000,0000,0000,,which are made of atoms that\Nare chemically bonded together
Dialogue: 0,0:05:14.94,0:05:17.79,Default,,0000,0000,0000,,in fixed ratios, like\Nwater or carbon dioxide.
Dialogue: 0,0:05:17.79,0:05:19.89,Default,,0000,0000,0000,,And when you physically\Nmix substances together,
Dialogue: 0,0:05:19.89,0:05:21.48,Default,,0000,0000,0000,,we get mixtures.
Dialogue: 0,0:05:21.48,0:05:23.67,Default,,0000,0000,0000,,Now, mixtures can be heterogeneous.
Dialogue: 0,0:05:23.67,0:05:25.80,Default,,0000,0000,0000,,If you can see the\Nindividual component apart
Dialogue: 0,0:05:25.80,0:05:27.87,Default,,0000,0000,0000,,with our naked eye, you can\Nsee the boundary, like say,
Dialogue: 0,0:05:27.87,0:05:31.53,Default,,0000,0000,0000,,when you add oil to water,\Nor they can be homogenous.
Dialogue: 0,0:05:31.53,0:05:32.36,Default,,0000,0000,0000,,In this case,
Dialogue: 0,0:05:32.36,0:05:34.74,Default,,0000,0000,0000,,the components are distributed\Nuniformly throughout,
Dialogue: 0,0:05:34.74,0:05:36.60,Default,,0000,0000,0000,,and so you cannot tell them apart.
Dialogue: 0,0:05:36.60,0:05:38.25,Default,,0000,0000,0000,,We also call them solutions.
Dialogue: 0,0:05:38.25,0:05:39.90,Default,,0000,0000,0000,,The component which is\Nin the less quantity,
Dialogue: 0,0:05:39.90,0:05:41.22,Default,,0000,0000,0000,,we call them as the solute,
Dialogue: 0,0:05:41.22,0:05:43.86,Default,,0000,0000,0000,,and the one with more quantity,\Nwe call them as a solvent.
Dialogue: 0,0:05:43.86,0:05:46.53,Default,,0000,0000,0000,,What's important is that the\Nindividual physical properties
Dialogue: 0,0:05:46.53,0:05:48.39,Default,,0000,0000,0000,,of the components, like\Ntheir boiling point,
Dialogue: 0,0:05:48.39,0:05:50.16,Default,,0000,0000,0000,,melting point, that does not change.
Dialogue: 0,0:05:50.16,0:05:53.37,Default,,0000,0000,0000,,And so, we can use that to\Nseparate them out physically.
Dialogue: 0,0:05:53.37,0:05:54.78,Default,,0000,0000,0000,,But a cool thing about solutions
Dialogue: 0,0:05:54.78,0:05:57.15,Default,,0000,0000,0000,,is that by varying the concentration,
Dialogue: 0,0:05:57.15,0:05:59.73,Default,,0000,0000,0000,,we can vary the properties\Nof the solutions
Dialogue: 0,0:05:59.73,0:06:01.14,Default,,0000,0000,0000,,to our advantage.