Chemistry - Ionic and Covalent bondings

bonkysleuth SG

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 SG

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.