Answer:

Explanation:
The mass of radioactive isotope at a certain time is given by the following expression:

Time constant can be calculed in terms of half-life:



The initial mass is:


Asteroids are made up of metals and rocky material , while comets are made up of ice ,dust and rocky material.
<span>2NaCN + (1)H2SO4 → Na2SO4 + 2HCN
</span><span>The coefficient of sulfuric acid is 1.</span>