The zinc in a 1.139g sample of a foot powder was precipitated as ZnNH4PO4. Strong heating of the precipitate yielded 0.4089g Zn2P2O7. Calculate the mass percent of zinc in the sample of foot powder.

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 .

Ais your answer to this