Because they insulate either the heat or the coolness within the food item. But keep in mind- when it comes to electricity aluminum isn’t an insulator.
I found a presentation of Food web of a pond that will greatly connect with the above problem. http://www.eduweb.com/portfolio/earthsystems/food/foodweb4.html
Normal setting:
Species Pop. size
Blue heron Medium
Perch Medium
Bass Medium
Minnows Medium
Inverts Medium
Algae Medium
If PERCH population size decreases,
Species Pop. sizeBlue heron LowPerch LowBass MediumMinnows HighInverts HighAlgae Low
As you can see, 4 other species are affected when the Perch population size decreased. Bass is not affected.
<h3><em><u>solution</u></em><em><u>:</u></em></h3>
<em><u>The initial entropy is obtained from the initial pressure and temperature with data from A-6 using interpolation:</u></em>
<em><u>s</u></em><em><u>=</u></em><em><u> </u></em><em><u>8</u></em><em><u>.</u></em><em><u>26</u></em><em><u>5</u></em><em><u>2</u></em><em><u> </u></em><em><u>kJ</u></em><em><u>/</u></em><em><u>kgK</u></em>
<em><u>The final temperature is determined from the entropy and the final pressure with data from A-6 using interpolation:</u></em>
<em><u>T₂ = T₁+</u></em><em><u> </u></em><em><u>T₂ - </u></em><em><u>T₁</u></em><em><u>/</u></em><em><u> </u></em><em><u>8</u></em><em><u>₂</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>8</u></em><em><u>₁</u></em><em><u> </u></em><em><u>(</u></em><em><u> </u></em><em><u>s</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>s</u></em><em><u>₁</u></em><em><u>)</u></em>
<em><u>= </u></em><em><u>(</u></em><em><u>400 +</u></em><em><u> </u></em><em><u>500 - 400</u></em><em><u>/</u></em><em><u>8.3271</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>8.0347</u></em><em><u> </u></em><em><u>(8.2652 - 8</u></em><em><u>)</u></em><em><u>)</u></em>
<em><u>= 478.83°C</u></em>
<em><u>The final enthalpy is determined in the same way:</u></em>
<em><u>h₂= h₁</u></em><em><u> </u></em><em><u>+</u></em><em><u> </u></em><em><u>h₂</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>h₁</u></em><em><u>/</u></em><em><u>s</u></em><em><u>₂</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>s</u></em><em><u>₁</u></em><em><u> </u></em><em><u>( s - s₁)</u></em>
<em><u>= (</u></em><em><u> </u></em><em><u>3275.5</u></em><em><u>+</u></em><em><u> </u></em><em><u>3486.6 </u></em><em><u>-</u></em><em><u> </u></em><em><u>3275.5</u></em><em><u>/</u></em><em><u> </u></em><em><u>8.3271</u></em><em><u> </u></em><em><u>-</u></em><em><u> </u></em><em><u>8.0347</u></em><em><u>)</u></em><em><u> </u></em><em><u>(8.265</u></em><em><u>)</u></em>
<em><u>=</u></em><em><u> </u></em><em><u>3441.91 </u></em><em><u>kJ</u></em><em><u>/</u></em><em><u>kg</u></em>
Selenium falls in the same column with oxygen therefore it has the same number of valence electrons with oxygen which is 6. It fills the 3d orbital but only 4s and 4p are counted. The electronic configuration is [Ar]3d^10 4s^2.
