1 (a) why is aluminium and copper used in making cooking pan ? (b) the melting point of silicon is 1410 c while that of chlorine is -101 c explain the difference. 2 with reference to chlorine (a) explain why most covalent compound are in gaseous at room temperature (b) why do silicon (IV)oxide,diamond and graphite exist as solid at room temperature ?
Answers
Answer:
1.(a) Clad aluminium or copper
Cladding is a technique for fabricating pans with a layer of efficient heat conducting material, such as copper or aluminum, covered on the cooking surface by a non-reactive material such as stainless steel, and often covered on the exterior aspect of the pan ("dual-clad") as well.
(b) The Editors of Encyclopaedia Britannica
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree...
Silicon (Si), a nonmetallic chemical element in the carbon family (Group 14 [IVa] of the periodic table). Silicon makes up 27.7 percent of Earth’s crust; it is the second most abundant element in the crust, being surpassed only by oxygen.
2. (a) In a covalent compound, the bond strength between atoms are strong. ... Since low melting points are mostly between the room temperature, the covalent compounds exist as liquids in room temperature. Some compounds have low boiling points also less than room temperature. Hence they exist as gases.
(b) The atoms within a sheet are held together by strong covalent bonds - stronger, in fact, than in diamond because of the additional bonding caused by the delocalised electrons. So what holds the sheets together? In graphite you have the ultimate example of van der Waals dispersion forces.