[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.09,0:00:05.07,Default,,0000,0000,0000,,In this video we're gonna look at how to\Nconvert back and forth between moles and
Dialogue: 0,0:00:05.07,0:00:08.00,Default,,0000,0000,0000,,the number of atoms or\Nmolecules that we have.
Dialogue: 0,0:00:08.00,0:00:10.36,Default,,0000,0000,0000,,Now, when we do conversions\Nlike this atoms and
Dialogue: 0,0:00:10.36,0:00:14.90,Default,,0000,0000,0000,,molecules are sometimes both\Nreferred to as particles.
Dialogue: 0,0:00:14.90,0:00:19.67,Default,,0000,0000,0000,,A particle is just a word for\Nany individual thing.
Dialogue: 0,0:00:19.67,0:00:24.65,Default,,0000,0000,0000,,So, a particle could be a jelly bean or\Na coin or a paperclip or
Dialogue: 0,0:00:24.65,0:00:26.68,Default,,0000,0000,0000,,an atom or a molecule.
Dialogue: 0,0:00:26.68,0:00:31.13,Default,,0000,0000,0000,,So, we'll work through problems like\Nthis where we have to go from moles to,
Dialogue: 0,0:00:31.13,0:00:36.68,Default,,0000,0000,0000,,say atoms, where we have to go from\Natoms and convert back to moles.
Dialogue: 0,0:00:36.68,0:00:38.91,Default,,0000,0000,0000,,Okay, so here's our first question.
Dialogue: 0,0:00:38.91,0:00:41.61,Default,,0000,0000,0000,,For each one of these problems and\Ndo it two ways.
Dialogue: 0,0:00:41.61,0:00:44.06,Default,,0000,0000,0000,,First, I’m gonna show you\Nhow to think through it,
Dialogue: 0,0:00:44.06,0:00:49.16,Default,,0000,0000,0000,,in kinda simple straightforward way, so\Nyou can understand what you’re doing.
Dialogue: 0,0:00:49.16,0:00:52.43,Default,,0000,0000,0000,,Then, I’m gonna show you how\Nto use conversion factors.
Dialogue: 0,0:00:52.43,0:00:54.88,Default,,0000,0000,0000,,I think conversion factors don’t\Nalways make a lot of sense and
Dialogue: 0,0:00:54.88,0:00:56.76,Default,,0000,0000,0000,,I know a lot of students\Nare confused by them.
Dialogue: 0,0:00:56.76,0:00:59.83,Default,,0000,0000,0000,,But, teachers and textbooks tend\Nto really like conversion factors.
Dialogue: 0,0:00:59.83,0:01:03.06,Default,,0000,0000,0000,,So, it's important to know how to solve\Nquestions like this using conversion
Dialogue: 0,0:01:03.06,0:01:04.44,Default,,0000,0000,0000,,factors, too.
Dialogue: 0,0:01:04.44,0:01:10.67,Default,,0000,0000,0000,,Okay so,\Nhow many atoms are in 5.5 moles of atoms?
Dialogue: 0,0:01:10.67,0:01:12.11,Default,,0000,0000,0000,,We're talking about moles and atoms here,
Dialogue: 0,0:01:12.11,0:01:15.21,Default,,0000,0000,0000,,so lets just refresh our\Nmemory about moles, okay?
Dialogue: 0,0:01:15.21,0:01:16.80,Default,,0000,0000,0000,,A mole is like a dozen, but
Dialogue: 0,0:01:16.80,0:01:23.43,Default,,0000,0000,0000,,there are 12 things in a dozen,and there\Nare 602 hexillion things in a mol.
Dialogue: 0,0:01:23.43,0:01:28.35,Default,,0000,0000,0000,,We often abbreviate this super\Nlong number with all these 0s,
Dialogue: 0,0:01:28.35,0:01:32.53,Default,,0000,0000,0000,,602 hexillion, as 6.02 x 10 to the 23rd.
Dialogue: 0,0:01:32.53,0:01:35.28,Default,,0000,0000,0000,,Mols can be a little bit tricky at first,\Nand so
Dialogue: 0,0:01:35.28,0:01:39.14,Default,,0000,0000,0000,,I wanna keep talking about\Nthe similarity to dozen.
Dialogue: 0,0:01:39.14,0:01:42.10,Default,,0000,0000,0000,,As we work through this first problem,\Nokay?
Dialogue: 0,0:01:42.10,0:01:45.95,Default,,0000,0000,0000,,We wanna know how many atoms\Nare in 5.5 moles of atoms.
Dialogue: 0,0:01:45.95,0:01:49.04,Default,,0000,0000,0000,,But, to get a handle on\Nhow to think through this,
Dialogue: 0,0:01:49.04,0:01:51.85,Default,,0000,0000,0000,,let's first think about how we\Nwould do this kind of problem
Dialogue: 0,0:01:51.85,0:01:54.87,Default,,0000,0000,0000,,if we were talking about\Ndozens instead of moles.
Dialogue: 0,0:01:56.21,0:02:00.53,Default,,0000,0000,0000,,So, what if instead of 5.5 moles\Nwe're talking about 5.5 dozen?
Dialogue: 0,0:02:00.53,0:02:03.39,Default,,0000,0000,0000,,Well, this math is probably\Npretty straightforward.
Dialogue: 0,0:02:03.39,0:02:05.79,Default,,0000,0000,0000,,There are 12 things in a dozen, so
Dialogue: 0,0:02:05.79,0:02:09.22,Default,,0000,0000,0000,,if you figure out how many\Natoms are in 5.5 dozen.
Dialogue: 0,0:02:09.22,0:02:14.21,Default,,0000,0000,0000,,We take 5.5 and then we multiply it by 12,\Nthe number of things in one dozen, and
Dialogue: 0,0:02:14.21,0:02:19.02,Default,,0000,0000,0000,,that would tell us how many atoms, or\Nhow many things, are in 5.5 dozen, okay?
Dialogue: 0,0:02:19.02,0:02:22.65,Default,,0000,0000,0000,,But, we're not talking about dozen here,\Nwe're talking about moles instead.
Dialogue: 0,0:02:22.65,0:02:26.72,Default,,0000,0000,0000,,So, instead of multiplying this by 12,\Nthe number of things in a dozen.
Dialogue: 0,0:02:26.72,0:02:29.24,Default,,0000,0000,0000,,We're gonna take 5.5 and\Nwe're gonna multiply it
Dialogue: 0,0:02:29.24,0:02:33.84,Default,,0000,0000,0000,,by 602,000,000,000,000,000,000,000,\Nthe number of things in one mole.
Dialogue: 0,0:02:36.06,0:02:40.55,Default,,0000,0000,0000,,Now, this big number here is\Na real pain with all the zeroes.
Dialogue: 0,0:02:40.55,0:02:43.32,Default,,0000,0000,0000,,And if you were actually\Ngonna do this math,
Dialogue: 0,0:02:43.32,0:02:46.56,Default,,0000,0000,0000,,chances are you wouldn't wanna\Nuse this long version here.
Dialogue: 0,0:02:46.56,0:02:50.38,Default,,0000,0000,0000,,You'd wanna use the shorter\Nversion in scientific notation.
Dialogue: 0,0:02:50.38,0:02:55.55,Default,,0000,0000,0000,,So, let's take this big number,\N602 hexillion,
Dialogue: 0,0:02:55.55,0:03:02.22,Default,,0000,0000,0000,,and write it in a more manageable\Nform of 6.02 x10 to the 23rd.
Dialogue: 0,0:03:02.22,0:03:04.36,Default,,0000,0000,0000,,This is the same number,
Dialogue: 0,0:03:04.36,0:03:09.13,Default,,0000,0000,0000,,6.02, as 602 hexillion,\Nit's just an abbreviated version here.
Dialogue: 0,0:03:09.13,0:03:10.79,Default,,0000,0000,0000,,So, you've written this out.
Dialogue: 0,0:03:10.79,0:03:13.96,Default,,0000,0000,0000,,Chances are you're going to use\Na calculator, scientific calculator or
Dialogue: 0,0:03:13.96,0:03:15.73,Default,,0000,0000,0000,,graphic calculator to solve this problem.
Dialogue: 0,0:03:15.73,0:03:22.71,Default,,0000,0000,0000,,So, here's how you're gonna\Ntype it 5.5*(6.02E23).
Dialogue: 0,0:03:22.71,0:03:26.97,Default,,0000,0000,0000,,Yes, E23 is usually how we do\Nexponents in a scientific calculator.
Dialogue: 0,0:03:26.97,0:03:29.79,Default,,0000,0000,0000,,The E is 10 to the exponent.
Dialogue: 0,0:03:29.79,0:03:32.64,Default,,0000,0000,0000,,And then 23 here is the exponent.
Dialogue: 0,0:03:32.64,0:03:37.69,Default,,0000,0000,0000,,Plug this into the calculator, and\Nwe're gonna get this as our final answer.
Dialogue: 0,0:03:37.69,0:03:41.23,Default,,0000,0000,0000,,There are two things that I\Nneed to do to this answer.
Dialogue: 0,0:03:41.23,0:03:45.89,Default,,0000,0000,0000,,The first thing I need to do is sorta take\Nit out of calculator scientific notation,
Dialogue: 0,0:03:45.89,0:03:48.84,Default,,0000,0000,0000,,and put it into normal\Nperson scientific notation.
Dialogue: 0,0:03:48.84,0:03:54.44,Default,,0000,0000,0000,,So, I'm gonna write 3.311E24
Dialogue: 0,0:03:54.44,0:03:58.69,Default,,0000,0000,0000,,is 10 to the 24th, okay?
Dialogue: 0,0:03:58.69,0:04:00.96,Default,,0000,0000,0000,,So now, it's in regular person\Nscientific notation but
Dialogue: 0,0:04:00.96,0:04:06.69,Default,,0000,0000,0000,,the next thing that we gotta do is take\Ninto account significant figures, okay?
Dialogue: 0,0:04:06.69,0:04:08.98,Default,,0000,0000,0000,,We'll look at the numbers\Nthat went into this,
Dialogue: 0,0:04:08.98,0:04:11.49,Default,,0000,0000,0000,,to figure out how to round it correctly,\Nokay?
Dialogue: 0,0:04:11.49,0:04:16.86,Default,,0000,0000,0000,,There are two significant figures in\N5.5 and there three significant figures
Dialogue: 0,0:04:16.86,0:04:22.79,Default,,0000,0000,0000,,in 6.02, so we're gonna round this number\Nto lower number of significant figures.
Dialogue: 0,0:04:22.79,0:04:25.00,Default,,0000,0000,0000,,We are gonna round it to two.
Dialogue: 0,0:04:25.00,0:04:27.87,Default,,0000,0000,0000,,Okay, so we are gonna take 3 and\Nwe gonna take this 3 and
Dialogue: 0,0:04:27.87,0:04:32.42,Default,,0000,0000,0000,,then we are gonna love the one to figure\Nwhether to round up or keep the same.
Dialogue: 0,0:04:32.42,0:04:35.21,Default,,0000,0000,0000,,It's a 1 its lower than 5 so\Nwe keep it the same.
Dialogue: 0,0:04:35.21,0:04:39.32,Default,,0000,0000,0000,,We'll do 3.3 x 10 to the 24th and
Dialogue: 0,0:04:39.32,0:04:43.44,Default,,0000,0000,0000,,what we're solving for here is atoms.
Dialogue: 0,0:04:45.04,0:04:47.71,Default,,0000,0000,0000,,This is our final answer.
Dialogue: 0,0:04:47.71,0:04:51.64,Default,,0000,0000,0000,,Now, so\Nmany people see a number like this,
Dialogue: 0,0:04:51.64,0:04:57.49,Default,,0000,0000,0000,,3.3 x 10 to the 24th, and\Nthey don't think of it as a real number.
Dialogue: 0,0:04:57.49,0:05:02.54,Default,,0000,0000,0000,,So, please keep in mind that this\Nnumber is just a shorthand for
Dialogue: 0,0:05:02.54,0:05:05.72,Default,,0000,0000,0000,,this super,\Nsuper long number with all these zeros.
Dialogue: 0,0:05:05.72,0:05:11.88,Default,,0000,0000,0000,,This is 3 heptillion,\N3 hundred hexillion atoms.
Dialogue: 0,0:05:11.88,0:05:13.81,Default,,0000,0000,0000,,Okay, so 3.3 x 10 is 24.
Dialogue: 0,0:05:13.81,0:05:15.99,Default,,0000,0000,0000,,It's not some weird martian number.
Dialogue: 0,0:05:15.99,0:05:21.54,Default,,0000,0000,0000,,Keep in mind, that it is just a shorthand\Nversion of this very long number here.
Dialogue: 0,0:05:21.54,0:05:25.89,Default,,0000,0000,0000,,And if for some reason, your teacher\Ndoesn't let you use a calculator and
Dialogue: 0,0:05:25.89,0:05:28.06,Default,,0000,0000,0000,,you have to do this out by hand.
Dialogue: 0,0:05:28.06,0:05:30.81,Default,,0000,0000,0000,,I have another video on\Ndoing more calculations
Dialogue: 0,0:05:30.81,0:05:32.21,Default,,0000,0000,0000,,by hand instead of a calculator.
Dialogue: 0,0:05:32.21,0:05:33.22,Default,,0000,0000,0000,,So, you can check that out.
Dialogue: 0,0:05:33.22,0:05:34.46,Default,,0000,0000,0000,,So anyway,
Dialogue: 0,0:05:34.46,0:05:39.21,Default,,0000,0000,0000,,this is how we do this problem using this\Nsort of simple straight forward method.
Dialogue: 0,0:05:39.21,0:05:43.48,Default,,0000,0000,0000,,We multiply 5.5 by the number of things\Nin one mole, plug in the calculator and
Dialogue: 0,0:05:43.48,0:05:44.76,Default,,0000,0000,0000,,this is what we get.
Dialogue: 0,0:05:44.76,0:05:47.89,Default,,0000,0000,0000,,Now, let's look at how we\Ncould solve the same problem
Dialogue: 0,0:05:47.89,0:05:49.75,Default,,0000,0000,0000,,using conversion factors instead.
Dialogue: 0,0:05:51.02,0:05:57.66,Default,,0000,0000,0000,,In this case, we're gonna be starting with\Nthis number here, 5.5 moles 5.5 moles.
Dialogue: 0,0:05:57.66,0:06:02.54,Default,,0000,0000,0000,,Now, we are going to want to multiply this\Nby a conversion factor that's going to get
Dialogue: 0,0:06:02.54,0:06:05.86,Default,,0000,0000,0000,,rid of moles and\Nis going to give us atoms.
Dialogue: 0,0:06:05.86,0:06:08.68,Default,,0000,0000,0000,,To write this conversion factor,\Nwe're going to think about moles.
Dialogue: 0,0:06:08.68,0:06:10.58,Default,,0000,0000,0000,,Let's look at this definition up here.
Dialogue: 0,0:06:10.58,0:06:16.09,Default,,0000,0000,0000,,I wanna rewrite this just as\Nan equation with an equals sign, okay?
Dialogue: 0,0:06:16.09,0:06:19.46,Default,,0000,0000,0000,,So, here we have 1 mole equals this much.
Dialogue: 0,0:06:19.46,0:06:21.45,Default,,0000,0000,0000,,I really haven't changed anything.
Dialogue: 0,0:06:21.45,0:06:25.38,Default,,0000,0000,0000,,But, I put the equals sign in here,\Nbecause we use relationships like
Dialogue: 0,0:06:25.38,0:06:28.94,Default,,0000,0000,0000,,this with one thing on either\Nside of the equals sign.
Dialogue: 0,0:06:28.94,0:06:32.87,Default,,0000,0000,0000,,We use relationships like this to\Nwrite conversion factors, okay?
Dialogue: 0,0:06:32.87,0:06:35.09,Default,,0000,0000,0000,,So, here's how we'll take\Nthis relationship and
Dialogue: 0,0:06:35.09,0:06:36.74,Default,,0000,0000,0000,,write a conversion factor.
Dialogue: 0,0:06:36.74,0:06:39.45,Default,,0000,0000,0000,,A conversion factor has both a top and\Na bottom.
Dialogue: 0,0:06:39.45,0:06:42.72,Default,,0000,0000,0000,,And we take something on one side\Nof the equation, one mole, and
Dialogue: 0,0:06:42.72,0:06:46.16,Default,,0000,0000,0000,,we can put it on, say,\Nthe top of the conversion factor.
Dialogue: 0,0:06:46.16,0:06:48.92,Default,,0000,0000,0000,,And then, the thing that's on\Nthe other side of the equal sign,
Dialogue: 0,0:06:48.92,0:06:50.05,Default,,0000,0000,0000,,we put that on the bottom.
Dialogue: 0,0:06:50.05,0:06:54.35,Default,,0000,0000,0000,,So, I'll do 6.02 x 10 to the 23rd.
Dialogue: 0,0:06:54.35,0:06:56.40,Default,,0000,0000,0000,,Things here, but\Nwe're talking about atoms.
Dialogue: 0,0:06:58.35,0:07:02.46,Default,,0000,0000,0000,,And this conversion factor is just telling\Nme that in one mole there are 6.02
Dialogue: 0,0:07:02.46,0:07:04.54,Default,,0000,0000,0000,,times 10 to the 23rd atoms.
Dialogue: 0,0:07:04.54,0:07:07.26,Default,,0000,0000,0000,,But, for every equation
Dialogue: 0,0:07:07.26,0:07:11.01,Default,,0000,0000,0000,,like this with an equal sign there are two\Nconversion factors that we can write.
Dialogue: 0,0:07:11.01,0:07:14.93,Default,,0000,0000,0000,,We can write it like this or\Nwe can flip it, that's cool too.
Dialogue: 0,0:07:14.93,0:07:20.19,Default,,0000,0000,0000,,So, I could also write 6.02\Nx 10 to the 23rd atoms
Dialogue: 0,0:07:20.19,0:07:23.42,Default,,0000,0000,0000,,on top, with 1 mole on the bottom.
Dialogue: 0,0:07:23.42,0:07:27.05,Default,,0000,0000,0000,,Now, both of these conversion\Nfactors are totally valid.
Dialogue: 0,0:07:27.05,0:07:30.15,Default,,0000,0000,0000,,Which one do we wanna use for\Nthis problem?
Dialogue: 0,0:07:30.15,0:07:34.34,Default,,0000,0000,0000,,Well, we wanna multiply this by a\Nconversion factor that's gonna get rid of
Dialogue: 0,0:07:34.34,0:07:36.14,Default,,0000,0000,0000,,moles, is gonna leave me with atoms.
Dialogue: 0,0:07:36.14,0:07:38.02,Default,,0000,0000,0000,,So moles is on top here.
Dialogue: 0,0:07:38.02,0:07:42.03,Default,,0000,0000,0000,,I'm gonna wanna choose the version\Nof this conversion factor
Dialogue: 0,0:07:42.03,0:07:45.66,Default,,0000,0000,0000,,that's going to give me moles on\Nthe bottom so they'll cancel out.
Dialogue: 0,0:07:45.66,0:07:46.64,Default,,0000,0000,0000,,So I'm gonna use this one.
Dialogue: 0,0:07:47.82,0:07:51.37,Default,,0000,0000,0000,,And then,\NI've got moles on the top here cancel out,
Dialogue: 0,0:07:51.37,0:07:53.46,Default,,0000,0000,0000,,moles on the bottom cancel out here.
Dialogue: 0,0:07:53.46,0:07:57.46,Default,,0000,0000,0000,,And that's gonna leave me with atoms,\Nokay.
Dialogue: 0,0:07:57.46,0:07:58.93,Default,,0000,0000,0000,,What's the math I'm gonna do?
Dialogue: 0,0:07:58.93,0:08:04.50,Default,,0000,0000,0000,,I'm gonna do 5.5 x 6.02 x10\Nto the 23rd divided by 1.
Dialogue: 0,0:08:04.50,0:08:08.82,Default,,0000,0000,0000,,Now, you might realize that\Ndividing this number by one
Dialogue: 0,0:08:08.82,0:08:10.38,Default,,0000,0000,0000,,doesn't really change anything.
Dialogue: 0,0:08:10.38,0:08:16.79,Default,,0000,0000,0000,,So, all the math we're really\Ndoing is just 5.5 x 6.02 x 10^23.
Dialogue: 0,0:08:16.79,0:08:19.10,Default,,0000,0000,0000,,Which is exactly what we did up here.
Dialogue: 0,0:08:19.10,0:08:23.13,Default,,0000,0000,0000,,So, you could just type this into your\Ncalculator and get this as an answer, or
Dialogue: 0,0:08:23.13,0:08:24.66,Default,,0000,0000,0000,,which would be totally fine.
Dialogue: 0,0:08:24.66,0:08:29.84,Default,,0000,0000,0000,,You could decide that you wanna put\Nthis whole conversion factor in and
Dialogue: 0,0:08:29.84,0:08:36.45,Default,,0000,0000,0000,,you could type it in like this 5.5 x and\Nthen parentheses 6.02E23 divided by 1.
Dialogue: 0,0:08:36.45,0:08:41.95,Default,,0000,0000,0000,,Whichever one you type in,\Nyou are going to get the same number here,
Dialogue: 0,0:08:41.95,0:08:47.13,Default,,0000,0000,0000,,which in regular person scientific\Nnotation is gonna look like this, and
Dialogue: 0,0:08:47.13,0:08:51.26,Default,,0000,0000,0000,,then we round it using sig\Nfigs to get this number here.
Dialogue: 0,0:08:51.26,0:08:56.05,Default,,0000,0000,0000,,Now, once again,\Ndon't forget that 3.3 x10 24,
Dialogue: 0,0:08:56.05,0:09:03.00,Default,,0000,0000,0000,,is just an abbreviated version of this\Nvery long number of atoms here, okay.
Dialogue: 0,0:09:03.00,0:09:07.06,Default,,0000,0000,0000,,So, that's how we go\Nfrom moles to say atoms.
Dialogue: 0,0:09:07.06,0:09:11.54,Default,,0000,0000,0000,,Now, let's look at how to do problems in\Nthe other direction from say atoms or
Dialogue: 0,0:09:11.54,0:09:14.02,Default,,0000,0000,0000,,molecules to number of moles.
Dialogue: 0,0:09:14.02,0:09:18.06,Default,,0000,0000,0000,,How many moles is 4.6 x 10\Nto the 24th Sulphur atoms?
Dialogue: 0,0:09:19.97,0:09:21.41,Default,,0000,0000,0000,,Okay, check out this number.
Dialogue: 0,0:09:21.41,0:09:24.48,Default,,0000,0000,0000,,I just wanna remind you that this\Nisn't some weird martian number,
Dialogue: 0,0:09:24.48,0:09:26.90,Default,,0000,0000,0000,,that this is just\Na shorthand abbreviation for
Dialogue: 0,0:09:26.90,0:09:30.19,Default,,0000,0000,0000,,this very long number with\Na whole bunch of zeros.
Dialogue: 0,0:09:31.26,0:09:32.29,Default,,0000,0000,0000,,As we did before,
Dialogue: 0,0:09:32.29,0:09:36.67,Default,,0000,0000,0000,,instead of jumping right to moles, Let's\Nredo this common sense approach, where we
Dialogue: 0,0:09:36.67,0:09:41.52,Default,,0000,0000,0000,,think about what we would do if instead\Nof moles we were talking about dozen.
Dialogue: 0,0:09:41.52,0:09:45.56,Default,,0000,0000,0000,,If we wanna know how many\Ndozen this big number were.
Dialogue: 0,0:09:45.56,0:09:48.73,Default,,0000,0000,0000,,Well, we'd recognize that there\Nare 12 things in dozen, and so
Dialogue: 0,0:09:48.73,0:09:52.52,Default,,0000,0000,0000,,we would divide this number by 12.
Dialogue: 0,0:09:52.52,0:09:58.47,Default,,0000,0000,0000,,12 things in a dozen,we wanna know how\Nmany times will 12 go into this one, okay?
Dialogue: 0,0:09:58.47,0:10:01.80,Default,,0000,0000,0000,,So, we are gonna be dividing by\Nthe number of things in a dozen.
Dialogue: 0,0:10:01.80,0:10:04.96,Default,,0000,0000,0000,,But, as before we are not talking about\Ndozens, we are talking about moles.
Dialogue: 0,0:10:04.96,0:10:07.52,Default,,0000,0000,0000,,So, instead of dividing by\Nthe number of things in a dozen,
Dialogue: 0,0:10:07.52,0:10:11.41,Default,,0000,0000,0000,,we wanna find out how many moles is it,\Nso we are going to divide.
Dialogue: 0,0:10:11.41,0:10:13.60,Default,,0000,0000,0000,,By the number of things in one mole.
Dialogue: 0,0:10:13.60,0:10:16.55,Default,,0000,0000,0000,,So, we're going to\Ndivide by 602 hexillion.
Dialogue: 0,0:10:18.42,0:10:22.51,Default,,0000,0000,0000,,As before, you're probably not\Ngonna wanna use these giant
Dialogue: 0,0:10:22.51,0:10:24.73,Default,,0000,0000,0000,,versions of each number\Nwith all these zeroes.
Dialogue: 0,0:10:24.73,0:10:27.77,Default,,0000,0000,0000,,So, this is where the scientific\Nnotation comes in handy.
Dialogue: 0,0:10:27.77,0:10:31.18,Default,,0000,0000,0000,,Let's rewrite this in scientific notation,\Nokay.
Dialogue: 0,0:10:31.18,0:10:35.59,Default,,0000,0000,0000,,We're 4.6 x 10 to the 24
Dialogue: 0,0:10:35.59,0:10:40.84,Default,,0000,0000,0000,,divided 6.02 x 10 to
Dialogue: 0,0:10:40.84,0:10:45.85,Default,,0000,0000,0000,,the 23, put this into the calculator.
Dialogue: 0,0:10:46.97,0:10:51.11,Default,,0000,0000,0000,,And you'll wanna type it in like\Nthis where we replace the 10 to
Dialogue: 0,0:10:51.11,0:10:54.04,Default,,0000,0000,0000,,the 24 with E24 or 10 x 23 with E23.
Dialogue: 0,0:10:56.42,0:11:00.18,Default,,0000,0000,0000,,Hit return, and\Nwe're gonna get a number like this.
Dialogue: 0,0:11:00.18,0:11:03.54,Default,,0000,0000,0000,,Now, it's not in scientific notation,\Nso we don't have to worry about that.
Dialogue: 0,0:11:03.54,0:11:08.91,Default,,0000,0000,0000,,But, we are going to want to round\Nthis with significant figures.
Dialogue: 0,0:11:08.91,0:11:12.41,Default,,0000,0000,0000,,There are two significant figures here,\Nthree significant figures here.
Dialogue: 0,0:11:12.41,0:11:15.00,Default,,0000,0000,0000,,So, we're gonna round this\Nto two significant figures.
Dialogue: 0,0:11:15.00,0:11:18.50,Default,,0000,0000,0000,,We're gonna take the 7 and the 6,
Dialogue: 0,0:11:18.50,0:11:21.19,Default,,0000,0000,0000,,look next door to figure out whether\Nwe round up or keep the same.
Dialogue: 0,0:11:21.19,0:11:23.18,Default,,0000,0000,0000,,It's a 4, so we keep it the same.
Dialogue: 0,0:11:23.18,0:11:24.91,Default,,0000,0000,0000,,And we're solving here for moles.
Dialogue: 0,0:11:24.91,0:11:30.34,Default,,0000,0000,0000,,It's gonna be 7.6 moles of sulfur atoms
Dialogue: 0,0:11:30.34,0:11:35.53,Default,,0000,0000,0000,,are in this super huge\Nnumber of Sulfur atoms.
Dialogue: 0,0:11:35.53,0:11:37.32,Default,,0000,0000,0000,,Okay, I am going to just stop.
Dialogue: 0,0:11:37.32,0:11:40.25,Default,,0000,0000,0000,,Slip it in right here, and
Dialogue: 0,0:11:40.25,0:11:44.69,Default,,0000,0000,0000,,now let's look at how we'd use conversion\Nfactors to solve this same problem.
Dialogue: 0,0:11:44.69,0:11:52.46,Default,,0000,0000,0000,,Okay, here we're gonna be starting\Nwith 4.6 x 10 to the 24th atoms.
Dialogue: 0,0:11:54.61,0:11:58.85,Default,,0000,0000,0000,,And we wanna multiple this by a conversion\Nfactor that's gonna get rid of atoms.
Dialogue: 0,0:11:58.85,0:12:03.26,Default,,0000,0000,0000,,And is going to move me to moles,\Nso let’s look at the two conversion
Dialogue: 0,0:12:03.26,0:12:07.61,Default,,0000,0000,0000,,factors that we could write using\Nthis relationship here, okay.
Dialogue: 0,0:12:07.61,0:12:12.70,Default,,0000,0000,0000,,The first one is gonna\Nput one mole on top.
Dialogue: 0,0:12:14.34,0:12:19.44,Default,,0000,0000,0000,,We are talking about atoms here,\Nso there are 6.02 x 10 to
Dialogue: 0,0:12:20.73,0:12:24.74,Default,,0000,0000,0000,,the 23rd atoms, in 1 mole.
Dialogue: 0,0:12:24.74,0:12:29.38,Default,,0000,0000,0000,,Or we could write this other conversion\Nfactor where we put 6.02 x 10 to
Dialogue: 0,0:12:29.38,0:12:31.80,Default,,0000,0000,0000,,the 23rd atoms on top and\N1 mole on the bottom.
Dialogue: 0,0:12:31.80,0:12:37.65,Default,,0000,0000,0000,,Which of these do we wanna use?
Dialogue: 0,0:12:37.65,0:12:41.30,Default,,0000,0000,0000,,We want to use the 1 that\Nis gonna get rid of atoms.
Dialogue: 0,0:12:41.30,0:12:43.30,Default,,0000,0000,0000,,Atoms is on the top up here,\Nit's on the bottom here.
Dialogue: 0,0:12:43.30,0:12:44.85,Default,,0000,0000,0000,,So, they're gonna cancel out.
Dialogue: 0,0:12:44.85,0:12:48.85,Default,,0000,0000,0000,,Okay, get rid of this.
Dialogue: 0,0:12:50.66,0:12:52.28,Default,,0000,0000,0000,,And now what's the math we're going to do?
Dialogue: 0,0:12:52.28,0:13:00.14,Default,,0000,0000,0000,,The math is going to be 4.6 x 10 to the\N24th x 1 divided by 6.02 x 10 to the 23rd.
Dialogue: 0,0:13:01.89,0:13:06.23,Default,,0000,0000,0000,,Now, multiplying this number by 1\Nisn't really gonna change anything.
Dialogue: 0,0:13:06.23,0:13:09.33,Default,,0000,0000,0000,,So, all we're really doing is\Nwe're taking this number and
Dialogue: 0,0:13:09.33,0:13:13.35,Default,,0000,0000,0000,,dividing it by this number,\Nthe exact same math that we did up here.
Dialogue: 0,0:13:13.35,0:13:17.93,Default,,0000,0000,0000,,But, just as we did previously, if you\Nprefer to put this as a big fraction into
Dialogue: 0,0:13:17.93,0:13:20.58,Default,,0000,0000,0000,,the calculator, that's totally cool too.
Dialogue: 0,0:13:20.58,0:13:24.87,Default,,0000,0000,0000,,It's gonnalook like this\N4.6E24 x this whole fraction,
Dialogue: 0,0:13:24.87,0:13:30.70,Default,,0000,0000,0000,,1/6.02 x10 to the 23, but all you're\Ndoing is just dividing this by this,
Dialogue: 0,0:13:30.70,0:13:34.28,Default,,0000,0000,0000,,because this 1 doesn't really matter.
Dialogue: 0,0:13:34.28,0:13:41.24,Default,,0000,0000,0000,,We're gonna get the same number here,\Nwhich rounds to 7.6 moles.
Dialogue: 0,0:13:41.24,0:13:45.69,Default,,0000,0000,0000,,So, that's how we go from a number\Nof things, like atoms, molecules,
Dialogue: 0,0:13:45.69,0:13:48.58,Default,,0000,0000,0000,,jellybeans or coins,\Nto figure out how many moles are in it.
Dialogue: 0,0:13:48.58,0:13:51.99,Default,,0000,0000,0000,,We divide it by the number\Nof things in 1 mole.
Dialogue: 0,0:13:51.99,0:13:55.76,Default,,0000,0000,0000,,Okay, so if you want some more practice\Nwith these kind of problems, check out
Dialogue: 0,0:13:55.76,0:13:59.39,Default,,0000,0000,0000,,the next video, converting between moles,\Natoms, and molecules part two.