page 884 kaplan blue book

[mgdent]

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on page 884 of the kaplan blue book, they give an example on how to find density at 2 atm and 45 degrees C but then go right into STP values when it's not at STP... I dont understand it so will just use D= (P*MM)/RT but if anyone gets that can they explain!

also, I am confused with electronic vs molecular dipoles. For example... water vs CH4.
Water has a bent molecular shape while CH4 is tetrahedral. Now I have written down that both bond and electronic dipoles for water are both tetrahedral and for CH4 there is no electronic but the bond dipole is tetrahedral... might have written this down wrong. Can anyone explain the difference between the 2 and what the answers should be. Thank you so much btw, everyone here is so helpful and supportive.

 

[rnbaxter]

on page 884 of the kaplan blue book, they give an example on how to find density at 2 atm and 45 degrees C but then go right into STP values when it's not at STP... I dont understand it so will just use D= (P*MM)/RT but if anyone gets that can they explain!

also, I am confused with electronic vs molecular dipoles. For example... water vs CH4.
Water has a bent molecular shape while CH4 is tetrahedral. Now I have written down that both bond and electronic dipoles for water are both tetrahedral and for CH4 there is no electronic but the bond dipole is tetrahedral... might have written this down wrong. Can anyone explain the difference between the 2 and what the answers should be. Thank you so much btw, everyone here is so helpful and supportive.

No idea what you are saying. All you need to know is:

Polar H20 has a bent molecular geometry due to its polar dipoles and a tetrahedral electron geometry.

Non-polar CH4 has a tetrahedral molecular geometry due to its 4 polar dipoles canceling out one another and a tetrahedral electron geometry.

 

[mgdent]

thank you!

 

[toothfairy05]

on page 884 of the kaplan blue book, they give an example on how to find density at 2 atm and 45 degrees C but then go right into STP values when it's not at STP... I dont understand it so will just use D= (P*MM)/RT but if anyone gets that can they explain!

I looked up your problem, they didn't use STP values...they adjusted all the values for 2 atm and 45 degrees by setting Pressure=(2atm/1atm) and Temperature=(318K/273K) to find the density.

Hope that helps.