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)

$$8.0 \times 10^{-6} mol\cdot dm^{-3}\times2.5\times 10^{-6}dm^3$$

$$=2\times10^{-11} mol$$

(b)

$$2.6 \times 10^{7}\times 3 \times 10^{-4} \times 1.3 \times 10^{3}$$

$$=1.014\times10^7$$