Hello! There are many indicators to show a sign that a chemical reaction has occured. These are 3 as followed.
1. An odor is produced.
2. A change in temperature.
3. A color change.
Others can be a formation of a solid or a gas.

Where r is the radius of balloon.
Here mass of woman = 68 kg
Mass of air displaced by a balloon with volume V = 1.29*V
Mass of helium inside balloon = 0.178*V
Total mass to be lifted by balloon = 68 +0.178*V
Buoyant force = 1.29V-0.178V=1.112V
So we have 1.112 V = 68+ 0.178*V
0.934 V = 68
V = 72.81 
\frac{4}{3} \pi r^{3}[/tex]= 72.81
r = 2.59 m
So radius of helium balloon = 2.59 m
<span>it fairly is going to attain a speed of 24 m/s in a 2d, yet between t = 0 and t = a million, it fairly is not any longer vacationing at that speed, yet at slower speeds. it fairly is 12 meters. ?D = [ ( a?T^2 + 2?Tv_i ) ] / 2 the place: ?D = displacement a = acceleration ?T = elapsed time v_i = preliminary speed ?D = [ ( 24m/s^2 • 1s • 1s + 2 • 1s • 0m/s ) ] / 2 ?D = 24 / 2 ?D = 12m</span>