Chemistry - Ionic and Covalent bondings

• bonkysleuth

  1 Jun 08, 20:11

  Substance                          electrical conductivity                    melting point

                      in solid state         in liq. state.     when dissolved in water

  A                 poor                           poor                  good                 -114 deg. cel.

  B                 good                          good                 good                     63

  C                 poor                           poor                  insoluble             1660

  D                good                          (sublimes)          insoluble             3730 (sublimes)

  E               poor                           good                    good                    772

  F                poor                            good                  insoluble               370

  G               poor                               good            good                        1074

   

  using letter A-G, select the substances with the following structures.

  i) giant ionic ___________

  ii) simple molecular__________

  iii) giant molecular_____________

  iv) metallic bonding______________

   

  state with a reason which substance could be potassium.

   

   

  URGENT HELP NEEDED. THANKS!

• UltimaOnline

  2 Jun 08, 00:53

  Based on all previous posts in which he chose not reply to assistance given therein, Bonkysleuth seems to be more interested in straight answers rather than understanding the underlying principles, which will be necessary if you/he wants to have a chance at scoring a distinction.

  Nonwithstanding, or regardless, since Bonkysleuth has put in the effort to type out the entire question, I'll give the correct answers directly, nothing more, nothing less.

   

  Substance                          electrical conductivity                    melting point

                      in solid state         in liq. state.     when dissolved in water

  A                 poor                           poor                  good                 -114 deg. cel.

  B                 good                          good                 good                     63

  C                 poor                           poor                  insoluble             1660

  D                good                          (sublimes)          insoluble             3730 (sublimes)

  E               poor                           good                    good                    772

  F                poor                            good                  insoluble               370

  G               poor                               good            good                        1074

   

  using letter A-G, select the substances with the following structures.

  i) giant ionic ___________ Echo, Foxtrot, Golf. 

  ii) simple molecular__________ Alpha (covalent gas which ionizes in water)

  iii) giant molecular_____________ Delta (graphite) and Charlie (silicon dioxide)

  iv) metallic bonding______________ Bravo (except that metals don't dissolve in water per se, rather, they react with water to form soluble ions/compounds in a redox reaction.)

   

  state with a reason which substance could be potassium.

  Obviously, Bravo. Low melting point. Reacts with water to form K+ and OH- ions that are available to conduct electricity. K is oxidized to K+ and 2H+ is reduced to H2 gas.

   

  URGENT HELP NEEDED. THANKS!

  You're welcome. A suggestion to you : try to want to truly understand and enjoy learning about the principles of chemistry for the sake of understanding the universe around you, rather than memorizing for the sake of school or marks or exams. Only when a student truly enjoys a subject, is the subject easy to score distinctions in, and fun, and worth studying. Of course, different people will naturally gravitate and excel in different subjects, eg. some love literature, some geography, some mathematics, etc. But no regardless, it's a universally understood pedagogical principle that students perform well in subjects they enjoy, and vice-versa. So as a student, the best way to improve in a subject is to (somehow!) enjoy it. Take care.