Answer:
[tex]\boxed {\boxed {\sf 0.068 \ mol \ NaCl}}[/tex]
Explanation:
To convert from molecules to moles, Avogadro's Number must be used. This number is 6.022 *10²³. It tells us the number of particles (atoms, molecules, etc.) in 1 mole of a substance.
In this case, the particles are molecules of sodium chloride. We can make a ratio.
[tex]\frac {6.022*10^{23} \ molecules \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Multiply by the given number of molecules.
[tex]4.1*10^{22} \ molecules \ NaCl *\frac {6.022*10^{23} \ molecules \ NaCl}{ 1 \ mol \ NaCl}[/tex]
Flip the fraction so the moles of sodium chloride cancel.
[tex]4.1*10^{22} \ molecules \ NaCl *\frac {1 \ mol \ NaCl}{6.022*10^{23} \ molecules \ NaCl }[/tex]
[tex]4.1*10^{22} *\frac {1 \ mol \ NaCl}{6.022*10^{23} }[/tex]
[tex]\frac {4.1*10^{22} \ mol \ NaCl}{6.022*10^{23} }[/tex]
[tex]0.06808369313 \ mol \ NaCl[/tex]
The original measurement of molecules has 2 significant figures, so our answer must have the same. For the number we calculated that is the thousandth place.
The 0 in the ten thousandth place tells us to leave the 8.
[tex]0.068 \ mol \ NaCl[/tex]
There are 0.068 moles of sodium chloride.
