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| 1. |
Calculate the molarity of the following Solution : (a) 30g of Co (NO3)2 . 6H2O in 4.3L of solution. |
| Answer» MASS of Co(NO₃)₂.6H₂O = 30gVolume of solution = 4.3 LTo find :Molarity of solutionFormula used :Number of mole = Mass ÷ molar massMolarity = Number of moles ÷ Volume of solution in LSolution :First of all we NEED to find molar mass of Co(NO₃)₂.6H₂O Molar mass of Co(NO₃)₂.6H₂O = ( 1 × Atomic mass of Co ) + 2 × [ ( 1 × Atomic mass of N ) + ( 3 × Atomic mass of O ) ] + 6 × [ ( 2 × Atomic mass of H ) + ( 1 × Atomic mass of O ) ]➝ Molar mass of Co(NO₃)₂.6H₂O = ( 1 × 59 ) + 2× [ (1×14) + (3×16) ] + 6×[ (2×1) + (1×16) ]➝ Molar mass of Co(NO₃)₂.6H₂O = 59 + 2×[ 14 + 48 ] + 6×[ 2 + 16 ] ➝ Molar mass of Co(NO₃)₂.6H₂O = 59 + (2×62) + (6×18)➝ Molar mass of Co(NO₃)₂.6H₂O = 59 + 124 + 108➝ Molar mass of Co(NO₃)₂.6H₂O = 291 g/mol_______________________________________________Number of mole of Co(NO₃)₂.6H₂O = mass ÷ molar mass➝ Number of mole of Co(NO₃)₂.6H₂O = 30G ÷ 291g/mol➝ Number of mole of Co(NO₃)₂.6H₂O = 0.1 mole_______________________________________________Molarity of solution = Number of mole of Co(NO₃)₂.6H₂O ÷ Volume of Solution in L➝ Molarity of solution = 0.1 mol ÷ 4.3 L➝ Molarity of solution = 0.023 M_______________________________________________ANSWER : 0.023 M | |