Question

How do you find the mass defect of nitrogen?

Answer 1

The mass defect is 0.108 506 u.

Explanation:

The mass defect is the difference between the calculated mass (the sum of the masses of the protons and neutrons) and the actual mass of the nucleus.

1. Calculate the total mass of the 7 protons and 7 neutrons in one nucleus of `""_7^14"N"`.

`"Calculated mass" = 7 color(red)(cancel(color(black)("protons"))) × "1.007 276 u"/(1 color(red)(cancel(color(black)("proton")))) + 7 color(red)(cancel(color(black)("neutrons"))) × "1.008 664 u"/ (1 color(red)(cancel(color(black)("neutron")))) = "7.050 932 u + 7.060 648 u" = "14.111 580 u"`

2. `"Actual mass of"color(white)(l) _7^14"N"= "14.003 074 u"`

3. Calculate the mass defect

`"Mass defect" = "calculated mass - actual mass" = "14.111 580 u - 14.003 074 u" = "0.108 506 u"`