Decanting Transitional Reasoning Download PDF

Questions

1. 1.

   A student thoroughly stirs coarse quartz sand, liquid water, and vegetable oil together in a glass beaker and lets the mixture stand undisturbed for twenty minutes. Observing three clearly defined layers due to insolubility and density differences, the student intends to separate the components using only the technique of decantation. Which procedure should the student follow, and which underlying property makes this decantation possible?

   • A) Pour the entire mixture across a paper filter because decantation relies on molecular size to trap the coarse sand while collecting an oil-water emulsion.
   • B) Carefully pour off the floating vegetable oil first and then pour off the water layer, because decantation relies on density differences and immiscibility to separate settled or stratified layers.
   • C) Heat the mixture until the vegetable oil evaporates completely, because decantation relies on differences in boiling points between liquids of differing densities.
   • D) Stir the mixture continuously while tilting the beaker, because decantation relies on uniform kinetic suspension to draw out the densest solid particles first.