In this video you are going to learn how

to write numbers in scientific notation and in standard form. Alright let’s do

this! hello-hello Melissa Maribel here and I help

students like you understand what you just learned in class so you stress less

and you graduate faster. Hit that subscribe button and we’ll pass

chemistry together. On to scientific notation. Scientific notation is just an

easier way to write really small or really large numbers. You will have two

different forms, standard form is just the expanded form of that number or the

number itself and scientific notation is just the condensed form of that same

number. The proper set up for scientific notation, you will always have one

non-zero number followed by a decimal then after that decimal you will have

one or more numbers. Doesn’t matter if it’s 0 or not and that would have been

times 10 to the some sort of exponent. So you’ll see for example we have 2.30×10 to the 4th. That is an example of your proper scientific notation. If

you wanted to then write a really really small number into scientific notation,

remember that all small numbers will have negative exponents when you put

them in scientific notation. So all numbers less than 1 have negative

exponents. Let’s try one. Write 0.0007211 in scientific notation. This is your clue

this is a very small number or it’s less than 1. So it will have a negative

exponent. What we’re going do, take that decimal place and we’re going to

move it all the way to that 7 because that is your first non-zero number. So

moving this over 1, 2, 3, & 4 putting our decimal place there, we know

that we will have a negative 4 as our exponent because that’s how many places

we move to get to that first nonzero number.

So our proper scientific notation is then 7.211×10 to the negative

4th. When we’re writing numbers that are already in scientific notation and going

back to standard form that exponent tells you whether or not

to move to the right or to the left. So if it’s negative you’re actually going

to move to the left and if it’s positive you’re gonna move to the right. 8.72×10 to -3rd we’re gonna write that in standard form. You’ll see that we have a -3 as our exponent so a -3 recall that tells us it’s going to be a

number that is less than one so we’re going to move the decimal place to the

left three. So I’m going to move this over one two and three and my decimal

place is here. I’m going to place a zero wherever I had any missing spaces and

our final answer is 0.00872. When you’re converting

really large numbers into scientific notation large numbers have positive

exponents. All numbers larger than one have positive exponents. For example

let’s write this ridiculously large number into scientific notation. So

clearly this is larger than 1 so we know it will have a positive exponent.

Your decimal place is always after the 0 or always after that last value

since there wasn’t initially a decimal place and we’re going to move this all

the way over to this 9 because that’s our first non-zero number. So I’m going

to just count one, two, three, four, five, six and seven. So our setup will be 9.0 and then following with all of the numbers that we had before times

10 to the positive 7. Seven because we move that decimal place over seven

times. Let’s write 1.489×10 to the 5th in standard form. Remember standard form now, is just the

expanded form of this number. That 5 tells us it’s a very large number. So

from that decimal place we’re going to actually move over to the right five

times. One, two, three, four, five, placing that decimal place here which

really it’s gone. This would have been zero and zero. The reason I say that that

decimal place is gone is because it’s now a really large number and there’s no

need to put a decimal place since there is no numbers following. So this would be

our correct number in standard form. Sometimes you have numbers that look

like they’re in scientific notation but they actually have two numbers in front

of that decimal place and we know that that’s not correct. So how do you change

them back? If you’re trying to move that decimal place to the left, you will add

how many decimal places you’re moving to that exponent. Now if you’re going the

other way if you’re going to the right, you’re actually going to subtract. I know

it’s always the opposite of what you’re thinking or what you’re used to, but

let’s try some. Though this number looks like it’s in scientific notation, it’s

not because remember we have to have one non-zero number in front of that decimal

place but instead we have two. So we have to move this decimal place over one,

whenever you move over one to the left you will add 1 to that exponent. So

instead we have 1.2409×10^-5 because we added a 1 to that exponent. Now we’re trying to move this decimal

place over one. When we move that over once to the right we will subtract this

exponent by one making it a negative four so when we move over to the left

you add and when we move to the right we subtract. Now it’s just you me and these

practice problems. For practice problems with

step-by-step answers, check the description box. Also let me know if you

want to see more “How to pass Chemistry” videos by liking and subscribing. And

leave a comment below letting me know why you want to pass chemistry and I’ll

see you next week.

Hi Melissa. To answer your question i'm studying chemistry because it's a very interesting subject. All these chemicals get mixed together and BOOM you get a change in colour…explosion…a gas etc. I'm thinking about taking a (BS) degree in chemistry. The thing is i'm not really sure about it because as you already know i have to be very good at maths and calculations. Maths has always been a problem for me. I have to look over and over again to understand something. I know it will cause a huge problem for me specially when it comes to practical chemistry. I'm not even sure if chemistry is the right major for me. I'm so confused and my mind is all over the place. University is such a big step for me and i don't know what to do. Sorry for the very long comment, but i have no one to talk to about this since i'm homeschooled.

Hi Melissa, I am studying Chemistry because I have to take it in High School LOL. I am currently a Junior. Chemistry is not my favorite subject at all-mostly because it's science and math combine- but your videos are the first ones I go to when I feel stuck. They are EXTREMELY helpful! Can you do a video on electron configurations sometime in the future? Would be very much appreciated:)

Thank you so much! I missed some school and have tons of work to catch up on and your channel (especially this video) Is so much help!

Can you do equations with scientific notation with the equation having subtracting an addition or multiplication with addition

MELISSA! I'm taking chemistry this semester and I'm not so good with math. I hope I pass this course using your helpful videos. If I don't pass then I believe Nursing ain't for me. ๐

Thank you so much! I relied on calculators so much but you make it so easy to learn without using a Calculator Thanks! Do you have a channel on how to convert metric conversions for volume, length, mass and height?

You're awesome, God has really blessed you with an amazing gift!!!

thank you! i was struggling to understand this and now it makes so much sense:)

kenz and destiny yall are correct…love u melissa

this. i need!

We are using this video to study chemistry ??

This helped a lot!

nice explanation keep making more video like this and thank you for your effort.

You looking so good

Remembering tip: remember LADD if going to the Left, then add.

Thank you so much!

THANK YOU SOOOO MUCH!! KEEP UP THE FANTABULOUS WORK!!!!!!!

Thank you for this video! My professor is very smart & explained it 5 different ways which confused me. Thankful for your time in putting this together ?