In a first order reaction, what fraction of the reactant will remain after 4 half-lives?

The answer is 1/16 because pretend you have a whole pie and every time you slice it, you cut it in halves...so therefore O is the whole pie, after the 1st half there's 1/2, after the second half life there is 1/4, after the third half life there is 1/8 and after the fourth half life you have 1/16 left. Hope I made it clear enough.

answer: the figure is attached herewith.

step-by-step explanation:   we are given to sketch a unit circle and label the terminal points corresponding to

in the attached figure, we have drawn a unit circle, with centre at o(0,0) and radius 1 unit. we have labelled the points a, b, c, d and e corresponding to the angles below

∠aox = 60°,

∠box = 120°,

∠cox = 180°,

∠dox = 240°,

∠eox = 300°.

and the coordinates are a(0.5,1), b(-0.5,1), c(-1,0), d(-0.5,-1) and e(0.5,-1).

thus, the answer is complete.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.