Homework Help: chemistry

Posted by Sarah on Friday, May 23, 2008 at 10:58am.

calculate number of atoms in 4.67 mol of Ca(NO3)2
I got:
2.81 X 10^24 C atoms or should it be 28.11 x 10^23 C atoms?
5.62 X 10^24 N atoms or should it be 9.34 x 10^23 N atoms?
1.69 x 10^25 O atoms....but are you allowed to do ^25 or should it be 168.7 X 10^23 O atoms I'm confused about exponents again.
also, do I need to worry about rounding to the correct number of signifcant digits when doing these questions?

chemistry - bobpursley, Friday, May 23, 2008 at 11:38am
Always round to the correct number of significant digits.

Proper scientific notation is X.SY*10^qr

2.84*10^24
5.62*10^24
1.69*10^25 are all correct.
- chemistry - BOB PURSLEY - Sarah, Friday, May 23, 2008 at 12:20pm
  would it have still been right if I didn't change the exponent, and say for C atoms, left it at 28.11 X 10^23?
chemistry - bobpursley, Friday, May 23, 2008 at 1:02pm
It is not in correct scientific notation, The number is of course, correct.

Answer this Question

Related Questions

chemistry - please help! - #1) how many atoms are represented by 2.0 mol of ...
chemistry - Calculate the mass, in grams, of each of the following. a) 1.2×...
chemistry - Can somebody please check my answer for this one? Calculate the ...
Science - How many atoms of aluminum can be produced by the decomposition of 47....
Chem - Superscript 15 How many moles of Pb is 9.3 X 1015 atoms of pb? 1 mol of ...
Chemistry - How would you approach a question like There are 6.02x 10 to the ...
chemistry - Calculate the following quantities. (See the periodic table.) (a) ...
chemistry - Find the mass in grams. a. 4.30 x 10^16 atoms He, 4.00 g/mol b. 5....
CHEMISTRY - what is the symbol for chromium (II) sulfate? You mean the formula? ...
Science - Chemistry - How many atoms are in 12g of Zinc? There are 6.02 x 10^23 ...

For Further Reading

First Name:
School Subject:
Answer: