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Question
The number of molecules in 4.25 g of ammonia is ______.
Options
1.0 x 1023
1.5 x 1023
2.0 x 1023
3.5 x 1023
Solution
The number of molecules in 4.25 g of ammonia is 1.5 x 1023.
Explanation:
Molecular mass of NH3 = 17 g
So, 17 g of NH3 has molecules= 6 x 1023
∴ 4.25 g of NH3 has molecules
= `425/(17 xx 100) xx 6 xx 10^23`
= `6/4 xx 10^23`
= 1.5 × 1023
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