D. Ratio of Neutrons to Protons
You need to find the formula mass of NaCl first, which you find the amu of both sodium and chlorine on the periodic table and you add them both. Then you divide the 175.5g by the formula mass which I got 58 g to get 3.026 moles of NaCl. 4 sig figs because of the 175.5. I recommend doing it on your own to make sure you get the right answer. You divide the 175.5g of NaCl by the formula mass.
Avogadro's number is 6.02<span> x </span><span>1023 atoms</span><span>. So, </span>6.02<span> x </span><span>1023 atoms</span><span> of sodium would have a mass of 23 g (sodium's relative atomic mass).</span>
<span> kg/m</span>³