First we have to understand what a half life is. A half life is a measure of time when the amount of a certain object is 50% of the original amount. Hence the answer for this is letter A. The initial amount is 100. fifty percent of 100 is 50 and that happens after 15 hours. Hence, 15 hours is the half life period.
Amount of Niobium-91 initially
= 300/91 =3.2967mol
2040 years = 3 ×680 = 3 half-lives
therefore, amount left = 0.4121mol
mass of Niobium-91 remaining = 0.4121 ×91 =37.5g
A wax is a type of lipid. Waxes are nonpolar, so they are not soluble in water.
They are all in forest climax means forest
