Dark colored moths survived better in the Industrial Revolution because their dark color helped them camouflage in soot. When the industrial revolution ended there wasn't as much soot, so the light colored moths now had a better chance of survival.
<span>HNO2 =====> H+ + NO2-
</span>I<span>nitial concentration</span> = 0.311
<span>C = -x,x,x </span>
<span>E = 0.311-x,x,x
</span>KNO2 ====>K+ + NO2-
<span>Initial concentration = 0.189 </span>
<span>C= -0.189,0.189,0.189 </span>
E = 0,0.189,0.189
Since you didn't give the actual volume (or any of the experimental values) I can only tell you how to do it. Do the calculation using the real (determined) volume of the flask. Then, re-do the calculation with v = 125ml. Take the two values and calculate % error; m = measured vol; g = guessed vol.
<span>[mW (m) - mW (g)]/mW (m) x 100% </span>
<span>(they want % error so, if it is negative, just get rid of the sign) </span>
Frequency, f = v / λ
f = 2.998 * 10⁸ / 3.55*10⁻⁸
f = 8.445 * 10¹⁵ Hz.