10 Pack Unknown Composition Potassium Hydrogen Phthalate Samples, 100g Each, Varying Purities 20 65% Chemical_Potassium Acid Phthalate NYS intermediate learning kit provides NYS intermediate learning kit provides guided inquiry experiments aligned with state standards for environmental chemistry and earth science instruction Fullerene C60 kit with 60 atoms and 90 bonds for building the spherical cage structure characteristic of fullerene carbon allotropes this 10 pack of 100g potassium hydrogen phthalate samples ranges 20 65% purity for analytical chemistry practice Used to challenge students in determining purity by titration of unknowns