Answer:
151.4863 years
Explanation:
Half life, t1/2 = 100 years
Initial concentration,[A]o = 100%
Final concentration, [A] = 35% (after 65% have been decayed)
Time = ?
Half life for a first Order reaction is given as;
t1/2 = ln (2) / k
k = ln(2) / 100
k = 0.00693y-1
The integral rate law for first order reactions is given as;
ln[A] = ln[A]o − kt
kt = ln[A]o - ln[A]
t = ( ln[A]o - ln[A]) / k
t = [ln(100) - ln(35)] /0.00693
t = 1.0498 / 0.00693
t = 151.4863 years
Answer:
Atoms
Explanation:
According to the law of conservation of matter, matter is neither created nor destroyed, so we must have the same number and kind of atoms after the chemical change as were present before the chemical change.
First calculate the electric charge used to deposit 1.0 g Pt
C = (1.0 g Pt) (1 mol Pt / 195.1 g Pt) ( 2 mol e / 1 mol Pt)
( 96485 C / 1 mol e)
C = 989.08 C
C = It
Where I is the current
T is the time
T = C / i
T = 989.08 C / 0.15 A
T = 6593.88 s
T = 1.83 hrs
