Author Question: Sometimes silica gel is dried in a microwave oven. Explain why the silica gel is hot to the touch ... (Read 112 times)

genevieve1028 · **on:** Aug 23, 2018

Sometimes silica gel is dried in a microwave oven. Explain why the silica gel is hot to the touch when removed from the oven even though it does not absorb appreciable amounts of microwave radiation.

Question 2

Some polymerization reactions are carried out using microwave energy. Although the reaction temperatures can be relatively high at the beginning of the reaction, they decrease as a function of time. Explain this observation, assuming that the monomer used in the polymerization reaction has a significant molecular dipole moment. An example of such a polymerization reaction is shown in Equation PE19.2.

Question 3

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leahchrapun · **Reply #1 on:** Aug 23, 2018

Answer to Question 1

The water within the silica gel is heated and eventually evaporates from the silica gel. Much of the heat that is generated from the water is transferred to the silica gel.

Answer to Question 2

Answer to Question 3

As the concentration of monomer decreases with time, the amount of polymer increases. The monomeric units within the polymer have restricted movement and dielectric heating is dramatically decreased, leading to a reduction in temperature with time.