Question

A chemist needs 0.0700 mol of potassium for a reaction. What mass of potassium should the chemist use?

2.737 g K
2.74 g K
39.1 g K

Answer 1

moles = mass divided by molar mass
\[moles (n) = \frac{ mass (m) }{Molar mass (M) }\]
So here we know the no. of moles and the molar mass of Potassium which is 39.0983 g per moles
if moles = mass divided by molar mass
then , mass = moles * molar mass
therefore mass = 0.07 * 39.0983= 2.737gK

Answer 2

ok that makes more sense thank you