To convert weight to moles, we must use the molar weight found on the periodic table. Sodium (Na) has a molar weight of 22.99 g/mol. So let's set up an equation and cancel out units:
[tex] \frac{1mole}{22.99g}*10.5g=0.4567mol=4.57*10^{-1}mol [/tex]
So now we know that 10.5g of sodium is equal to 0.4567 moles.
