largest number that can go into 6.022 x 10^23 without changing it
yes, i know that but i need to find the largest number to go into it with out changing the 6.022 * 10^23 form.
1?
or 1X10^0?
1 is the only thing that will go into anything without changing it, except zero.
the largest number you can add to it.
1.00X10^0
9?
In chemistry, 6.022× 1023 is an important number called the Avogadro constant (or Avogadro\'s number). It expresses the number of atoms or molecules in a mole. Notice that it is a really, really big number, as indicated by scientific notation with a large positive exponent. Enter 6.022× 1023 into the calculator shown here. Then, by trial and error, find the largest number that can be added to 6.022× 1023 without changing its displayed value (as shown on the screen).
6.22X10^23=622000000000000000000000 (+9) = 6220000000000000000000009, or 6.22X10623+ hmmmm... 1.0X10^21?
6.022* 10^23 not 0.022 X 1023
yeah, so you're learning about sig figs?
so you have how many sig figs?
3?
uhm, I think that looks like 4, personally. I could be wrong.
6.022
i meant 4
so now you need to know how take that 6.022 to 6.0224
because, that would keep your sig figs at 6.022 right?
I have no idea to be honest.
so you need something that starts with a 4 and has a lot of 9's after it (because it's the highest number that will not change your 4 sig figs.
99999999999999 goes into it without changing but it isnt the correct answer.
so tell me, how would you express 6.02249999999999999999999 in scientific notation?
to 4 sig figs, that is
6.022 * 10^23
I would write 6.022x10^23 b/c you can't round up to 6.023... because the number after your 4th sig fig is a 4
I am so confused.
if i would add the to the problem it would change it.
ha ha so if I said, round 6022.49 to 4 significant figures, what would you write?
6022
yeah, that's what I would write. I am assuming if I gave you the same question with the numbers 6022.50000001, you'd write something different?
what
you'd round that up to 6023
I would
so what I am thinking, is that your number is 4.99x10^x
why x?
well, the x is for you to figure out!
you've made me more confused than I already was :/
I don't want to answer it for you, I want to put you on the right track
I am sorry, so you want to add some number to 6.022X10^23, without changing that. So in order to do that, you need to think of the highest possible number that you would add that would NOT affect how you'd round that figure of 6.022x10^23. if you had 6.0225X10^23, you'd have to express that as 6.023X10^23 if you only could use 4 sig figs
BUT, if you had 6.0224X10^23, and you had to write it with only 4 sig figs, you would write 6.022x10^23, right?
Maybe I should back up, are you learning significant figures in chemistry right now, is that what this problem is?
I am assuming so. Im sorry but I am so confused and Yes, I am.
well we are suppose to be learning it, but my teacher didnt really teach anything of it beside the definition.
okay, fair enough. So if the problem gives you 6.022X10^23, they want the answer with 4 significant figures, in this case they want 6.022. Now, they want you to NOT change the number at all, and that includes the exponent, so they want 6.022X10^23 to be expressed exactly as is.
They are asking, what is the highest possible value that you can have, and still express the number as 6.022X10^23
but if you add something, you change the number am i mistaken
so you need to find the number that is 1 less than the lowest number that would force you to round up. If that number (the lowest one that would force you to change your written number) is 5.0X10^20, which would equal 6.0225X10^23, or 6.023X10^23(with 4 sig figs), you need to subtract 1 from that.
yes, you change the value, but we are rounding!
if your sales tax is 8.25% on $1, can you pay $1.0825? Nope, you have to round it, so the cashier says your total is $1.08. In that case, the highest sales tax that would make you still pay $1.08 is 8.49%, because the cashier still HAS to round down.
i feel like a complete idiot right now.
This is the exact same concept. 6.022499999...X10^23 is the answer. Expressed as scientific notation, that would be 4.9X10^19, I think.
Don't! I'm probably just not explaining it well. I will try again.
round 9.5 to the nearest whole number for me.
10
round 10.4 to the nearest whole number for me.
10
two different values, yet still the same answer, yes?
yes
what is the maximum number I can add to 10 that, rounding, will still give me 10?
4
nope, that would give you 14
because if its 5 you round up
.4
yup!
now if I asked for the highest number to 10 decimal places that would still leave me with 10, you'd say 10.4999999999, right?
no because the .4 would round up to 5 making it 11?
it would make its 10.5 which is considered 11
ohh, that's good logic! but if you think about it in whole values, you'd say your threshold for rounding up or down is 50%, so if I have 49.99999%, I have LESS than 50%, so I can't round up.
but that does round up to 50 because of the .999999
Sure, I could round 49.999 to 50, but because I have less than 50, I can't round 5.499999 to 5.50, because that second 5 is not really five, it's a 4 with a bunch of 9's after it.
Yup! the 4.99999 rounds up to 5.0, but the 5.49999999 does not round up to 6. It rounds up to 5.5
okay.
ionly round one number, not both.
so how could 10.499999999 round up to 11? It could round up to 10.5, but we are looking for just whole numbers in my example
Yes, because you are more than half of the whole number off! .499999 < half
yes, I understand what you are saying. We are rounding to the nearest tenth, not whole. correct?
yes, so if I asked to round to the nearest whole, you couldn't make that jump because you don't have enough (money, weight, pencils, etc) to say that.
correct.
so, what's the most I could add to 6.022X10^23 that would STILL leave me with 6.022X10^23?
probably 6.022499999999...., that would round to 6.0225, but not to 6.023!
make sense?
kinda
okay, so if you had $.499999 in the bank do you think the bank would let you withdraw $1? I mean, why not, you could round it up to $.50, and they'd probably let you withdraw $.50, but they'd NEVER let you round that up to $1, you don't even have half of a dollar!
ohh! I understand that.
now apply that to Avogadro's number and see what you get!
so take 6.022 *10^23 plus 4.99999999?
no thats not right.
well, that last 2 is what you want to add your 4.9999 to but it's such a large number that you'd probably think of it as 49999.... count the 9's write it as 4.99X10^x where x=the number of 9's you've counted.
4.99 * 10^14
so 6.022x10^23 has 23 numbers (21 of them are zeros) before the decimal point, if you were to write that number out. 6.022X10^23 = 602200000000000000000000
am I even close?
499999999999999+602200000000000000000000=?
not that correct answer.
remember, you're trying to get to 6.02249999999999999999999, right?
+0.0004999999?
+0.000049X10^23, yes, because with scientific notation you can't express the 9's after your last sig fig.
four 0000 not three?
0.000049 * 10^23 would be my answer?
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