Answer:
90yrs
Explanation:
Half life is the time taken for half of an original radioactive material to decay by half.
For the sample;
Half - life = 45yrs
Original amount = 600cpm
Start Number of atoms
0yrs 600cpm
First half life
45yrs 300cpm
Second half life
90yrs 150cpm
Answer:
The correct answer is periods. See the explanation below, please.
Explanation:
The horizontal lines in the periodic table are called periods (ranging from 1 to 7) and vertical lines (ranging from 1 to 18).
The period that an element belongs to coincides with the last electronic layer of the element (that compound in period 3 will have 2 electronic layers).
Answer:
reversible reaction or covalent bonds
Let A be the 80% solution and B be the 20% solution and P be the produce solution of 70%. Va and Vb and Vp are the volumes of A and B and P respectively.
Va + 60 = Vp
0.7Vp = 0.8Va + 0.2(60)
Substituting the value of Vp from the first equation:
0.7(Va + 60) = 0.8Va + 12
30 = 0.1Va
Va = 300 gallons
