Grade 12Physical Chemistry
The number of atoms present in 4.25 grams of NH3 is approximately
4 Answers
Arun
Molar mass NH3 = 14+3 = 17g/mol
given mass = 4.25g
no of moles = 4.25/17 = 0.25 mol of NH3
1 mol of NH3 contains 6.022*10^23 molecules
0.25 mol NH3 contains 0.25*6.022*10^23 = 1.5055*10^23 molecules
1 molecule of NH3 contains 4 atoms
Number of atoms in 1.5055*10^23 molecules = 4*1.5055*10^23 atoms.
The correct answer is = 6.022*10^23 atoms
Chhavi Jain
Dear student ,
the molar mass of NH3 = 14 + 3*1 =17
now, we will first calculate the no. of moles of NH3 :
no. of moles = given mass / molar mass
= 4.25 / 17 =0.25 moles of NH3
as , in 1 mole of NH3, no. of molecules of NH3 = 6.022 * 1023 ( Avogadro’s number )
therefore, in 0.25 moles of NH3 , no. of molecules of NH3 = 0.25 * 6.022 * 1023 = 1.5055 * 1023
as we know, in 1 molecule of NH3 , no. of atoms = 4 ( 1 atom of nitrogen and 3 atoms of hydrogen )
so, in 1.5055 *1023 molucules of NH3 , total no. of atoms = 4 * 1.5055 * 1023 = 6.022 * 1023 atoms
Chemistry Consultant
askiitians
Anjali kumari
As mole=given mass/molecular mass.So mole of NH3 =4.25/20=425/2000. = 0.25 mole So number of atoms=0.25×6.022×10^23 atoms.
Anjali kumari
As molecular mass of NH3 is 14+3=17g.And as moke= given mass /molecular mass=4.25/17= 0.25mole Now number of atims=0,.25×6.022×10^23 atoms.
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