Final answer:
To find the mass of 1.43 x 10^28 atoms of potassium, you need to calculate the number of moles. The molar amount of a substance can be calculated by dividing its mass in grams by its molar mass. Referring to the periodic table, the atomic mass of K (potassium) is 39.10 amu, so its molar mass is 39.10 g/mol.
Step-by-step explanation:
The mass of K is provided, and the corresponding amount of K in moles is requested. Referring to the periodic table, the atomic mass of K is 39.10 amu, and so its molar mass is 39.10 g/mol. The given mass of K (4.7 g) is a bit more than one-tenth the molar mass (39.10 g), so a reasonable "ballpark" estimate of the number of moles would be slightly greater than 0.1 mol.
The molar amount of a substance may be calculated by dividing its mass (g) by its molar mass (g/mol):