There are 2 grams remain
<h3>Further explanation</h3>
Given
t1/2 = 30 years
t = 170 years
No = 100 g
Required
Remaining sample
Solution
General formulas used in decay:

Input the value :

Explanation:
100 liter because it is measured
Take 82 grams and divide it by the gfm of water which is 18 g/mole...(82g)/(18.0g/mole)=4.555 -> the answer is 4.6 moles