friday, 10/27
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Compounds and Elements Atomic, molecular, and network matter Chemical formulas Molecular families and bonding geometries Instrumentation. Friday, 10/27. Compounds and Elements Atomic, molecular, and network matter Chemical formulas Molecular families and bonding geometries - PowerPoint PPT PresentationTRANSCRIPT
Friday, 10/27
• Compounds and Elements
• Atomic, molecular, and network matter
• Chemical formulas• Molecular families and
bonding geometries• Instrumentation
Friday, 10/27
• Compounds and Elements
• Atomic, molecular, and network matter
• Chemical formulas• Molecular families and
bonding geometries• Instrumentation (?)
• The wave model tells us what atoms are like
• We can understand how atoms bond
• These bonds are a major part of our daily experience.
• Our lives are governed largely by chemistry
Why we’re doing this
Our approach
• 10/27 Atoms molecules and networks
• 10/30 Reactivity• 11/1 Bonding in metals
and semiconductors• 11/3 Ionic bonds• 11/6 Covalent bonds• 11/8 Some applications
• The wave model tells us what atoms are like
• We can understand how atoms bond
• These bonds are a major part of our daily experience.
• Our lives are governed largely by chemistry
Why we’re doing this
(Participation question)Which of these is a compound?
Hydrogen
Neon Nitrogen
Water
25% 25%25%25%1. Hydrogen
2. Neon
3. Nitrogen
4. Water
Compounds: matter that contains two or more atoms in a fixed, definite proportion.
Sulfuric acid, hydrogen peroxide, salt, sugar, bleach, sodium bicarbonate, etc.
(Participation Question)What is the difference between a pure substance
and an element?
They are the same thing Pure substances hav... Elements have a defi...
33% 33%33%1. They are the same
thing2. Pure substances have a
defined, unchanging chemical composition, but elements are just one kind of atom.
3. Elements have a defined, unchanging chemical composition, but pure substances are just one kind of atom.
Chemical Matter
Chemical Matter
• Atomic Matter: The noble gases
• Simple atoms in solid, gas, and liquid state
“I told you they’s organized”
Molecular matter
• Definite molecules in solid, liquid, and gaseous states
• Atomic Matter: The noble gases
• Simple atoms in solid, gas, and liquid state
“I told you they’s organized”
Molecular matter
• Definite molecules in solid, liquid, and gaseous states
• Extended bonding, no distinct molecles.
• Metals, salt, quartz, etc.
Network matter
Can you tell how bonding influences melting and boiling temperatures?
atomic
molecular
network
molecular
(Participation question)How many hydrogen atoms:
H2O
1 2 3 4 5
20% 20% 20%20%20%1. 1
2. 2
3. 3
4. 4
5. 5
(Participation question)How many hydrogen atoms:
2C2H4
2 4 6 8 10
20% 20% 20%20%20%1. 2
2. 4
3. 6
4. 8
5. 10
The family of simple hydrocarbons
http://ps100.byu.edu/molecule_sg/simple_hydrocarbons.html
Molecular Orbitals
• Electrons in molecules have NEW standing wave descriptions
• Sometimes we talk about shared pairs of electrons
Molecular Orbitals
• Electrons in molecules have NEW standing wave descriptions
• Sometimes we talk about shared pairs of electrons
Molecules vibrate
Infrared Absorption
• Molecular vibration can be caused by photon absorption
Molecules vibrate
Infrared Absorption
• Molecular vibration can be caused by photon absorption
Molecules break
Mass Spectroscopy
• Measure molecular fragments to determine the original molecule
Molecules break
Mass Spectroscopy
• Measure molecular fragments to determine the original molecule
• Some molecules can be formed into crystals
• Crystal form and content determined by x-ray scattering
Molecules crystallize