Find the number of moles in 87g of K2SO4 (K=39u, S=32u, O=16u).

Sure, here are the steps to find the number of moles in 87g of K2SO4:

1. First, calculate the molar mass of K2SO4. The molar mass is the sum of the atomic masses of all the atoms in a molecule. The atomic masses of K, S, and O are given as 39u, 32u, and 16u respectively.

   For K2SO4, there are 2 atoms of K, 1 atom of S, and 4 atoms of O. So, the molar mass would be: (239u) + (132u) + (4*16u) = 78u + 32u + 64u = 174u

2. The number of moles of a substance is given by the formula: Number of moles = mass of the substance / molar mass of the substance

3. Substituting the given mass of K2SO4 (87g) and the calculated molar mass (174u) into the formula, we get: Number of moles = 87g / 174g/mol = 0.5 mol

So, there are 0.5 moles in 87g of K2SO4.