What is the percent by mass of potassium in k3fe(cn)6?
16.96%
21.88%
25.53%
35.62%

The percent mass of potassium in K3Fe(CN)6 is 35.62%. The molar mass (Mr) of K3Fe(CN)6 is the sum of atomic masses (Ar) of its elements. Ar(K) = 39.1 g/mol, Ar(Fe) = 55.84 g/mol; Ar(C) = 12.01 g/mol; Ar(N) = 14.01 g/mol. Mr(K3Fe(CN)6) = 3Ar(K) + Ar(Fe) + 6Ar(C) + 6Ar(N) = 3 * 39.1 + 55.85 + 6 * 12.01 + 6 * 14.01 = 117.3 + 55.85 + 72.06 + 84.06 = 329.27 g/mol. There are 3 atoms of K, so total mass of K in K3Fe(CN)6 is: 3Ar(K) = 3 * 39.1 = 117.3 g/mol. In percents, this is: 329.27 : 100% = 117.3 : x. x = 100% * 117.3 : 329.27 = 35.62%

Elias is almost correct. he just got it backwards.the correct answer is that it demonstrates elastic potential energy transforming into kinetic energy.

The air is going to come out because of the low pressure.