A solution contains Al 3 and Co 2 . The addition of 0.3657 L of 1.676 M NaOH results in the complete precipitation of the ions as Al ( OH ) 3 and Co ( OH ) 2 . The total mass of the precipitate is 21.72 g . Find the masses of Al 3 and Co 2 in the solution.

catya that's not even a b or c

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter  

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.