Final answer:
The mass of 3.5 moles of sodium hydroxide (NaOH) is 139.99 g.
Step-by-step explanation:
In order to calculate the mass of 3.5 moles of sodium hydroxide (NaOH), we need to determine the molar mass of NaOH first. The molar mass of NaOH is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). Using the given atomic masses from the periodic table, we calculate:
Na: 22.990 g/mol x 1 = 22.990 g/mol
O: 15.999 g/mol x 1 = 15.999 g/mol
H: 1.008 g/mol x 1 = 1.008 g/mol
Adding up these values, we find that the molar mass of NaOH is 39.997 g/mol. Therefore, the mass of 3.5 moles of NaOH is:
39.997 g/mol x 3.5 mol = 139.99 g