How many Cr atoms in 78.82 g potassium dichromate?(adsbygoogle = window.adsbygoogle || []).push({});

Potassium dichromate is [tex]\textrm{K}_{2}\textrm{Cr}_{2}\textrm{O}_{7}[/tex].

I said:

The molecular mass of potassium dichromate is:

39.1*2+52*2+16*7=294.2

So, in 78.82 g potassium dichromate, there are 78.82/294.2= 0.2680 moles of potassium dichromate. Each mole of potassium dichromate has [tex]6.022~x~10^{23}[/tex] molecules, each with 2 chromium atoms. So, in one mole, there are [tex]1.204~×~10^{24}[/tex] chromium atoms. So, in .2680 moles, there are [tex].2680(1.2044~×~10^{24})~=~3.228~×~10^{23}[/tex], correct?

As a sidenote, it appears that LaTeX graphical formulas can't be seen in the preview mode -- the only way to check them is to post the message then edit the message if they're wrong? Also, where can I find a better LaTeX tutorial than https://www.physicsforums.com/misc/howtolatex.pdf which just doesn't give enough information? Ah, https://www.physicsforums.com/showthread.php?t=9021 has some pretty good information, but I still don't seem to be doing my LaTeX correctly.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# How many Cr atoms in 78.82 g potassium dichromate?

**Physics Forums | Science Articles, Homework Help, Discussion**