1 mol of Carbon = 12 grams.
x mol of Carbon = 55 grams
12*x = 1 * 55
x = 55/12
x = 4.583333 mols of carbon
1 mol of anything is 6.02 * 10^23 atoms
4.58333333 mol = x
1/4.5833333 = 6.02 * 10^23/x
x = 4.58333* 6.02*10^23
x = 2.7591 * 10^23 Carbon atoms
Neutrons were discovered by James Chadwick<span> in 1932, when he demonstrated that penetrating radiation incorporated beams of neutral particles. Neutrons are located in the nucleus with the protons. Along with protons, they make up almost all of the mass of the </span>atom<span>.
Hope this helps. </span>
Let's write the equation

According to law of conservation of mass .
- Mass of products=Mass of reactants
Let required value be x




Density * Volume = Mass
Now we substitute the values in.
19.3 g/cm^3 + 20 cm^3 = 386 g
Mass = 386 g