How many neutrons does a calcium atom have if the mass number is 42

22

Explanation:

calcium has 20 proteins

and given the mass number is 42.

mass number = protons + neutrons

42= 20+ n

n= 42-20

n= 22

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

you did not give any options thus this is the best answer i can give to you with this little information you have given

> they are both natural and not man made

> they can be tracked and predicted by the right tools

-love shrooms