Answer:
The half life is 
Explanation:
The half life of a first order reaction is mathematically represented as
Substituting 
for the rate constant
Answer is: chemical.
Making a pancake from batter is chemical change (chemical reaction), because new substances are formed, the atoms are rearranged and the reaction is followed by an energy change.
Batter is thin dough that is poured into a pan to make pancakes.
In physical change, the same substance is present before and after the psysical change, just with different form or state of matter.
Answer:
2 half-lives=0.8
6 half-lives= 0.05
Explanation
Half-lives are constant and always decrease by half, implying that the concentration decreases by half at a consistent rate.
3.2/2= 1.6/2= 0.8 is two half-lives
3.2/2= 1.6/2= 0.8/2= 0.4/2= 0.2/2= 0.1/2=0.05 is six half-lives
