Which of these statements best explains why pure water has a ph of 7?
1) pure water contains only h20 molecules, but ph is based on the concentration of h30+ ions.
2)each molecule of water can dissociate to form 7 h30+ ions.
3) water self-ionizes to form an equilibrium system that has [h30+]=1.0x10^-7m

Water self-ionizes to form an equilibrium system that has [h30+]=1.0*10^-7M

Your answer is C

A neutral solution would have a pH of 7, which means that the acid and base concentrations are equal. For the case of water, the concentrations of H3O+ and OH- are equal, which is 1.0 x 10^-7 M. Thus, the 3rd statement best explains the neutral pH of water.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .