help me

[tigertiger No.3640954]

>chemistry retard here, need help. just started at uni and doing significant figures, problem is

(3.52 times 10^-11) / (7.823 times 10^11)

>get 4.49955E^-23 on calculator
>wtf, answer is 0.450times10^-22
>freaking out right now

[Anonymous No.3640965]

Calculator gives scientific notation. 4.50E-23 is the same thing as 0.450E-22

[Anonymous No.3640967]

>-22
>-23

Look at the decimal places of each answer.

But seriously, you're dividing two numbers of equal powers, so your answer is 0.450, with no powers.

[tigertiger No.3640968]

>>3640965
wow i am really really dumb
thanks man!

[Anonymous No.3640972]

>>3640967

Eh, scratch that second part. Didn't realize they were one positive and the other negative.

[Anonymous No.3640985]

Is OP retarded or trolling?

[tigertiger No.3640990]

>>3640985

i haven't even taken calculus yet
so E is a mysterious thing to me

[Anonymous No.3640999]

>>3640990
>Calculus
>E

[Anonymous No.3641013]

>>3640954
Here's how you should look at this.

(3.52 * 10^-11)(7.823 * 10^11) is the question given.

You can multiply in any order. So...

=(3.52 * 7.823)(10^-11 * 10^11)
=(27.53696)(10^0)
=27.5, after sig figs.

The idea is that you can multiply all the scientific notation separately from the actual significant digits, and doing so makes the answers a bit more obvious.

[Anonymous No.3641017]

OP I'm learning the same shit as you I'm taking general college chem as a high school senior (AP chemistry).

I don't know how much you already know of this info, but I'll try to help.

-When dividing and multiplying numbers, always round your answer to the least number of sig figs used in the calculation. For example, 4.50*9=40. 9 has the least # of sig figs (1) so you answer has to have 1 as well.

-When adding/subtracting, always use the least amount of DECIMAL places that were used in your calculation. For example, 5.44-2=3.

non zero integers are ALWAYS sig figs

3 kinds of zeros-

leading zeros - ex. 0.0004555 are NEVER sig figs

captive zeros - ex. 5005 has 4 sig figs, you count the 2 "captive" zeros in the number

trailing zeros - ex. 0.000500 has 3 sig figs. remember, leading zeros never count as sig figs. IMPORTANT- trailing zeros only count as sig figs if there is a decimal point in the number. 500 has 1 sig fig.

hope that helped

[Anonymous No.3641018]

>>3641013
I'm a retard and multiplied instead of divided. Whoops!

[tigertiger No.3641032]

>>3641017
i think i love you
>>3641013
didn't know you could do that! i'll use it for multiplying then

[Anonymous No.3641043]

ITT: people trolling me bigtime with their fail in maths.

[Anonymous No.3641047]

>>3641043

Welcome to /sci/.

[Anonymous No.3641053]

>>3641047
I only wonder if it's on purpose ...

[Anonymous No.3641061]

>>3641053

Only about half of it. Here, have this image macro. It will come in handy when replying to threads on this board.

[Anonymous No.3641074]

>>3641061
I take this as an invitation to come here more often ...

[Anonymous No.3641075]

>>3641032
love u too sweetheart.

btw i forgot to tell u about rounding.

consider the problem 6.348-2.0

since it's subtraction, we round to the least number of decimal places used in the problem right? so we would end up with
6.348 , and then have to round it to 2 sig figs.

BE CAREFUL, do not say 6.348 -->6.35 -->6.4

you have to round AT the sig fig

the answer is 6.3 because you only look at the number IMMEDIATELY to the right of the sig fig.
6.34 rounds to 6.3, don't fuck with the 8.

[Anonymous No.3641084]

>>3641074

Well, you can't possibly make this place any worse. Pull up a chair and stay a while. You might unlearn a thing or two, but what's the fun in always being right?

[Anonymous No.3641093]

>>3641075
how is it
that you are explaining it better than my teacher?
i have got it now and am finishing my work

[Anonymous No.3641116]

>>3641093
your teacher must be awful.. sig figs aren't bad, they're really just a list of rules that you have to apply to certain calculations. good luck in chem this year , i know i'm gonna need it too..

by the way, I know know if your college requires you to get a textbook or anything, or if you have one... but if you can, get Zumdahl's Chemistry 5th edition. It's pretty good at delivering concepts to the reader without cluster fucking everything.