How many grams of nickel (ii) chloride hexahydrate are required to prepare 250. ml of aqueous solution whose concentration is 0.255 m? the molar mass of nickel (ii) chloride hexahydrate is 237.69 g mol−1.

15.2 grams

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

where,

n= moles of solute

  = volume of solution in ml

moles of solute (nickel (II) chloride hexahydrate ) =

Putting the values , we get

Thus 15.2 grams of nickel (II) chloride hexahydrate are required to prepare 250. mL of aqueous solution whose concentration is 0.255 M.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"