It is an imaginary line called the axis.
Mass number is the sum of protons and neutrons inside an atom.
Atomic mass = no. of protons + no. of neutrons
Answer:
are a gas at very low volumes, when gas particles are very close together
a gas at very low temperatures, when gas particles have very little kinetic energy
a gas with highly polar molecules that have very strong intermolecular forces
Explanation:
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
