Assume a substance has a half-life of 19 years and the initial amount is 132 grams. How long will it be until only 35 % remains?

The answer to the question is

It will be ≅ 28.8 years until only 35 % of the substance remains

Explanation:

To solve this we note the required relations and the given variables thus

The half life of the substance is

N(t) = N(0) ×

Thus when only 35% is remaining we have

35% of N(0) = N(0)×

or 0.35 =   , to solve the previous equation, we take the log of both sides thus

Log (0.35) = Log ( ) or × log (1/2) =log(0.35)

⇒   = 1.515 and since = 19 years we have

t = 19 × 1.515 = 28.776 Years

Therefore it will be 28.776 years before 35 % of the substance will be remaining

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.

each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i