Chemistry Experiment 9.1

January 16, 2014 Peter Fenger 

Experiment 9.1 Polar Covalent vs. Purely Covalent Compounds I. Purpose

The purpose of this experiment is to see the electrical changes that polar covalent compounds and  purely covalent compounds mae! " covalent #ond is a #ond in $hich the electrons are shared e%ually  #et$een the atoms involved! " polar #ond on the other hand, is a covalent #ond in $hich the electrons are shared une%ually #et$een the atoms involved! II. II. Hypo Hypoth thes esis is

&f a molecule is polar covalent then, it is electrically charged! III. Materials/Supplies Materials/Supplies •

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'ater from the tap or sin  (egeta#le )il *tyrofoam or paper cup com# " person $illing to use their hair for the experiment Pen

IV. IV. Procedure Procedure

1! tae the pen pen and punch a small small hole hole into the #ottom #ottom of the the cup +the +the smaller smaller the hole hole the #etter #etter 2! 'hile holding holding your your cup over the the sin, sin, pour some some $ater into into the cup from from the glass! glass! -ae -ae sure the $ater is streaming out of the hole not .ust dripping! /! 'hen the $ater $ater is pouring pouring out out of the cup in in a steady stream, stream, tae tae the com# com# and vigorously vigorously com# your hair  4! 'hen you have com#ed com#ed your hair, hair, #ring the the com# +#ristles +#ristles first first near the stream stream of $ater! $ater! ! epeat this this experiment experiment using using vegeta#le vegeta#le oil oil instead instead of $ater $ater o#serving o#serving $hat happens happens!! 6! lea lean n up up you yourr mes mess! s! V. ! !ser serva vatio tion n and "at "ata a

1! The first first hole hole punch $e did $as good, $e did not need to do do another another one! 2! The $ater $ater stre streame amed d out in in a good stea steady dy strea stream! m! /! *omeone in in our class class #rought #rought a metal com# com# and so it did did not $or $ith $ith the first first try try #ecause #ecause in chemistry metal al$ays messes messes things up! 3o$ever $hen $e used a plastic com# it finally $ored after com#ing someones hair the $ater $a ter $as finally reacting! 4! 5ringing 5ringing the com# com# near the $ater $ater very close close to to the $ater #ut #ut not actually actually touching touching it, it, caused the the $ater to move side$ays some of the $ater $a ter coming closer to the com# in a #ending motion other   parts of the $ater moving a$ay from the com#!

January 16, 2014 Peter Fenger  ! 'hen $e repeated the experiment $ith oil nothing happened!

VI. Conclusion

'hat made the oil stream #end, #ut the vegeta#le oil not #end The ans$er is that $ater is a polar covalent compound, $hile vegeta#le oil is purely covalent! &n a $ater molecule, electrons are #eing shared #et$een hydrogen atoms and the oxygen atom! The oxygen atom $ins the tug of $ar for electrons so it develops a partial negative charge! The hydrogen electrons have a slight electron deficit giving them a partial positive charge! 'hen our demonstrator com#ed his hair the com# #ecame negatively charged! *o $hen $e put the com# up close to the $ater the positive charge in the $ater $as attracted to the com#, $hile the negative charge in the $ater moved a$ay from the com#! This is $hat made the $ater #end7 electrical attraction! The vegeta#le oil on the other hand, is a purely covalent compound so it is not electrically charged and that is $hy nothing happened $e put the com# next to it! *ince $ater, a polar covalent molecule, $as proven in this experiment to have an electrical charge it  proves that my hypothesis is correct!