Answer:
approximately equal to 152 grams of uranium
Step-by-step explanation:
1. to find the number of atoms in 25.0 grams of potassium, we can find the number of moles of potassium in 25.0 g by dividing that by the molar mass (found on a standard IUPAC periodic table) and then multiply that by Avogadro's constant, the number of 'items' (molecules, atoms, ions, etc...), which is 6.022×10²³ to get the number of atoms in 25.0 g of potassium.
n(K) = m/M = 25.0/39.10 = 0.639386... mol of potassium.
N(K) = n×Nₐ = 0.639386...×6.022×10²³ = 3.85038...×10²³ atoms
2. In uranium, 3.85038...×10²³ atoms also equals 0.639386... moles. We can multiply this number by the molar mass of uranium (grams per mole), to get the mass of uranium.
m(U) = nM = 0.639386...×238.0 = 152.1738...
Therefore, the mass of uranium which contains the same number of atoms as 25.0 g of potassium ≈ 152 g