Question

PLEASE!!! I NEED HELP ASAP!!

Answer 1

W=m₁/m₀=2^(-t/T)

t=4.6·10⁹ years
T=5·10¹⁰ years

w=2^(-4.6·10⁹/5·10¹⁰)

w=0.9382
w=93.82%

Answer 2

Answer:

the ratio of parent to daughter =  15.38 : 1

Explanation:

The radioactive disintegration is considered to be first order reaction.

The relation between first order rate constant and the half life is:

$k=\frac{0.693}{t_{\frac{1}{2} }}$

Let us calculate the rate constant from half life as

$k=\frac{0.693}{50}=0.01386 (billionyr)^{-1}$

The rate law expression for first order reaction is

$kt=ln\frac{[A0]}{At}$

Where

A0 = initial amount of rubidium isotope = say 100

At= final amount of rubidium isotope after 4.6 billion years

putting all values

$0.1386X4.6=ln\frac{100}{At}$

1.065=100/At

At=93.897

The amount of daughter isotope formed =100-93.897 = 6.103

the ratio of parent to daughter = 93.897:6.103 = 15.38 : 1