Question

(a)  Given the formula:-

Moles  = Concentration(Moldm^-3) X Volume(dm³)

            

Use the formula to find the number of moles in

2.5 X 10 ^-6 dm³ of a 8.0 X 10 ^-6 moldm^-3 solution of potassium   permanganate.

(b)           Evaluate showing your working out without calculator use:-     

           2.6x10⁷ x 3x10^-4      

                        1.3 x 10³   

Answer 1

(a) $2.5*10^{-6}*8*10^{-6}=20.8*10^{-12}\approx 2*10^{-11}\;mol.$

(b) $2.6*10^7*3*10^{-4}=7.8*10^3=7800.$

$1.3*10^3=1300.$