Question

How do i use the factor-label method to calculate the number of grams of kmno4 that you would need to make 100 ml of a 0.0045 m potassium permanganate solution?

Answer 1

Factor-label, also known as dimensional analysis, describes a technique to convert one quantity - a length, mass or anything else for that matter - to another quantity.
V(KMnO₄) = 100 ml.
c(KMnO₄) = 0,0045 mol/l = 0,0000045 mol/ml.
m(KMnO₄) = V(KMnO₄) · c(KMnO₄) · M(KMnO₄).
m(KMnO₄) = 100 ml/1 · 0,0000045 mol/ml · 158 g/mol.
m(KMnO₄) = 0,0711 g.