The purple crystalline solid potassium permanganate forms a purple solution when dissolved in water.

I believe the above is an example of a physical change
Physical changes alter the physical form of substances without changing their chemical identities. A physical change may involve changing the state of a substance, such as melting ice, or changing the shape or the size of the pieces in a sample. Other physical changes involve the formation of mixtures in which all of the components retain their chemical identifies, such as dissolving sugar in water. 

About 8 gallons of fuel will be used. (8.08)

Rn in the right answer