How many Ta atoms are found in a 1.321 g sample of Ta?

Question

anonymous · Answer

I set it up as 1.231 x ((2.06 x 10^23)/(180.94)) and got 1.40.  I'm not sure what I did wrong

anonymous · Answer

I'm sure it's just the syntax you've put in your calculator. Break it down by steps. 

You have 1.231 grams of tantalum, and your mR reference value is 180.94. This gives you 6.80 millimoles (6x10^-3). 

If you have 1 mole then that's 6.022*10^23 atoms, so just multiply the number of moles you have by avogadros number and you'll get 4.10*10^21 atoms

If you need more sig figs, give it a try

anonymous · Answer

@pking8786 is right. The problem is that you might put the wrong value for $\sf N_A$. The Avogadro's number is $6.022\times 10^{23}$.