10) How many grams are there in 3.8times 10^23 molecules of Nalo?

To solve this problem, we need to find the mass of $3.8\times 10^{23}$ molecules of NaI (sodium iodide).<br /><br />Given information:<br />- The number of molecules of NaI is $3.8\times 10^{23}$.<br /><br />Step 1: Find the molar mass of NaI.<br />Molar mass of NaI = Molar mass of Na + Molar mass of I<br />Molar mass of NaI = 22.99 g/mol + 126.90 g/mol = 149.89 g/mol<br /><br />Step 2: Calculate the number of moles of NaI.<br />Number of moles = Number of molecules / Avogadro's number<br />Number of moles = $3.8\times 10^{23}$ molecules / $6.022\times 10^{23}$ molecules/mol<br />Number of moles = 0.631 moles<br /><br />Step 3: Calculate the mass of NaI.<br />Mass = Number of moles × Molar mass<br />Mass = 0.631 moles × 149.89 g/mol<br />Mass = 94.9 grams<br /><br />Therefore, there are 94.9 grams in $3.8\times 10^{23}$ molecules of NaI.