Hey there!
A half-life means after a certain amount of time, half of that substance will gave decayed after that time.
So, we divide the 120 atom sample in half 3 times.
120 ÷ 2 = 60
60 ÷ 2 = 30
30 ÷ 2 = 15
There will be 15 atoms of the radioactive sample remaining after three half lives.
Hope this helps!
Answer:
Explanation:
The nuclear model of the atom was suggested by Ernest Rutherford based on his experiment on a thin gold foil.
To explain his observations, he suggested the atomic or nuclear model.
In this model, the atom has a small positively charged center called the nucleus.
All the mass of the atom is concentrated here in the nucleus.
Surrounding the nucleus is a large space
It is the extranuclear part
This part contains electrons.
A nucleus surrounded by electrons forms the nuclear model of the atom.
This
can be solved using Dalton's Law of Partial pressures. This law states that the
total pressure exerted by a gas mixture is equal to the sum of the partial
pressure of each gas in the mixture as if it exist alone in a container. In
order to solve, we need the partial pressures of the gases given. Calculations
are as follows:<span>
P = P1 + P2 + P3
<span>P = (0.08206 atm.L/mol.K)( 298.15
K)/1.50) x (0.158 mole + 0.09 mol + 0.044 mol) = <span>4.76
atm</span></span></span>
