Monday, January 14, 2008
Mon-Day 1
Bio - we had our Digestive and Endocrine System exam.
We discussed our Salivary Amylase and Protein Digestion labs, which are posted on Blackboard. You will put those in your lab folders on Wednesday.
Tomorrow, we begin a three-system unit: the Respiratory, Circulatory, and Excretory systems.
We will discuss the major structures within these systems and the function/purpose of each structure in helping the body perform its life processes. We will be gradually outlining chapter 37 of our text for this unit.
Chem 7- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)
We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.
We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.
NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.
MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.
METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).
Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared. Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.
Chem 8/9- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)
We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.
We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.
NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.
MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.
METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).
We then finished our conductivity lab and began to go over the write-up, which we will continue tomorrow as part of our review for Wednesday's exam.
Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.
Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.
We discussed our Salivary Amylase and Protein Digestion labs, which are posted on Blackboard. You will put those in your lab folders on Wednesday.
Tomorrow, we begin a three-system unit: the Respiratory, Circulatory, and Excretory systems.
We will discuss the major structures within these systems and the function/purpose of each structure in helping the body perform its life processes. We will be gradually outlining chapter 37 of our text for this unit.
Chem 7- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)
We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.
We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.
NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.
MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.
METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).
Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared. Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.
Chem 8/9- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)
We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.
We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.
NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.
MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.
METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).
We then finished our conductivity lab and began to go over the write-up, which we will continue tomorrow as part of our review for Wednesday's exam.
Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.
Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.
# posted by C @ 12:45 PM 
