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Topic: [EMERGENCY!!!] Please help me ASAP (9/4/2009)  (Read 2273 times)

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Offline zerox0o

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[EMERGENCY!!!] Please help me ASAP (9/4/2009)
« on: September 04, 2009, 02:38:40 PM »
i have to do these 2 problems, but i keep on getting them wrong. please help me asap!!! it's urgent please!!!

3. A sample of electrons is found to have a total charge of -2.24x10^10C. How many electrons are in this sample?
Enter numeric answer only.

 
 
(i did -2.24x10^10 C/ 1.602176487x10^-19) = -1.398e29  <<< but it's wrong T__T
 
4. What is the mas of the above sample of electrons in grams?
Enter a numerica answer only.


( i did  -1.398e29 x9.1093826x10^-28) = -127.349g and it's wrong T__T

PLEASE HELP ME!!! pleas :(

Offline Borek

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Re: [EMERGENCY!!!] Please help me ASAP (9/4/2009)
« Reply #1 on: September 04, 2009, 02:49:58 PM »
You can't have negative number of electrons. Besides, 1010x10-19 is not 1029.
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Offline renge ishyo

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Re: [EMERGENCY!!!] Please help me ASAP (9/4/2009)
« Reply #2 on: September 04, 2009, 04:34:14 PM »
If you get the right answer for number 3 then you will get the right answer for number 4 as the steps are correct for number 4. Use a calculator for number 3 if you need to, putting all the scientific notation terms in parenthesis between each operation.

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