Question

how many number of molecules presents in 7.4 g of ninhydrin ?

Answer 1

Chemical formula of Ninhydrin is C₉H₆O₄ 
Molar mass = 9×12 + 6×1 + 4×16 = 108+6+64 = 178g

178 gram of Ninhydrin contains = 1 mole = 6.022×10²³ molecules
1 gram of Ninhydrin contains = 6.022×10²³/178 molecules
7.4 gram of Ninhydrin contains = 7.4×6.022×10²³/178 = 2.561×10²² molecules

So number of molecules in 7.4 gram Ninhydrin is 2.561×10²² molecules.

Answer 2

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Chemical formula of Ninhydrin is C₉H₆O₄ 

Molar mass = 9×12 + 6×1 + 4×16 = 108+6+64 = 178g

178 gram of Ninhydrin contains = 1 mole = 6.022×10²³ molecules

1 gram of Ninhydrin contains = 6.022×10²³/178 molecules

7.4 gram of Ninhydrin contains = 7.4×6.022×10²³/178 = 2.561×10²² molecules

So number of molecules in 7.4 gram Ninhydrin is 2.561×10²² molecules.

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