To calculate the total number of neutrons in 7mg of C^14, we need to know the atomic mass of C^14 and the number of protons it has. The atomic number of carbon is 6, which means it has 6 protons in its nucleus. C^14 is a radioactive isotope of carbon, which means it has 6 protons and 8 neutrons in its nucleus.

The atomic mass of C^14 is 14, which means it has a total of 14 particles in its nucleus. To find the number of neutrons in C^14, we subtract the number of protons (6) from the total number of particles (14). Therefore, the number of neutrons in C^14 is:

14 - 6 = 8

This means that each atom of C^14 has 8 neutrons in its nucleus. To find the total number of neutrons in 7mg of C^14, we need to use Avogadro's number, which is 6.022 x 10^23 particles per mole. We can use this number to convert the mass of C^14 into the number of moles, and then multiply by the number of neutrons per mole:

Number of moles of C^14 = Mass of C^14 / Atomic mass of C^14
= 7mg / 14 g/mol
= 0.0005 mol

Total number of neutrons in 7mg of C^14 = Number of moles of C^14 x Avogadro's number x Number of neutrons per mole
= 0.0005 mol x 6.022 x 10^23 particles/mol x 8 neutrons/particle
= 2.41 x 10^20 neutrons

Therefore, the total number of neutrons in 7mg of C^14 is 2.41 x 10^20 neutrons.



To calculate the total mass of neutrons in 7mg of C^14, we can use the mass of a single neutron, which is approximately 1.0087 atomic mass units (u). Therefore, the mass of 8 neutrons is:

8 neutrons x 1.0087 u/neutron = 8.0696 u

To find the total mass of neutrons in 7mg of C^14, we need to use the total number of neutrons we calculated earlier and multiply by the mass of a single neutron:

Total mass of neutrons in 7mg of C^14 = Total number of neutrons x Mass of a single neutron
= 2.41 x 10^20 neutrons x 1.0087 u/neutron
= 2.43 x 10^20 u

To convert this mass into grams, we can use the conversion factor 1 u = 1.6605 x 10^-27 kg:

Total mass of neutrons in 7mg of C^14 = 2.43 x 10^20 u x 1.6605 x 10^-27 kg/u x 10^3 g/kg

I)carbon has 6 atomic no= no of protons
mass no= no of protons+no of neutrons
14=6+n
8=n
ii)no of atoms in 1mole=6.022*10^23
no of atoms in 7mg =0.007/14 *6.022*20^23
=5*10-4*6.022*10^23
=30.1*10^19
=3.01*10^20
therefore no of neutrons in 7mg of c=8*3.01*10^20
=24.08*10^20
=2.41*10^21
mass of one neutron=1.67*10-27kg
mass of 2.41*10^21neutrons=2.41*10^21*(1.67*10^-27)
=4.02*10-6kg