Calculate the amounts of the substance in order to prepare a certain amount of the solution

   I have tried using Molarity= Moles of Solute/Liters of Solution, but i cannot figure the answer out. If you can only get the first two questions, that is okay, thank you!

1) Calculate the amount of potassium ferrocyanide trihydrate [K4Fe(CN)6•3H2O] needed to prepare 250 ml of 0.025 M solution. 

2) Calculate the amount of zinc sulfate heptahydrate [ZnSO4•7H2O] needed to prepare 250 ml of 0.050 M solution. 

3) Assuming that the actual molarities of your stock solutions are equal to the target molarities given above, calculate what titration volume of zinc sulfate would be expected for titrating  a 25.00 ml aliquot of the ferrocyanide solution for each of the five  possible reactions presented below:

   K4Fe(CN)6(aq)  +  ZnSO4(aq) -----> K2ZnFe(CN)6(s)  +  K2SO4(aq)

   K4Fe(CN)6(aq)  +  2 ZnSO4(aq) ----> Zn2Fe(CN)6(s)  +  2 K2SO4(aq)

   2 K4Fe(CN)6(aq)  +  ZnSO4(aq) ----> K6Zn[Fe(CN)6]2(s)  +  K2SO4(aq)

   2 K4Fe(CN)6(aq)  +  3 ZnSO4(aq) ----> K2Zn3[Fe(CN)6]2(s)  +  3 K2SO4(aq)

   3 K4Fe(CN)6(aq)  +  2 ZnSO4(aq) ----> K8Zn2[Fe(CN)6]3(s)  +  2 K2SO4(aq)