intro to chemistry bio 117... · intro to chemistry chapter 2 . learning objectives • define the...
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INTRO TO CHEMISTRY CHAPTER 2
LEARNING OBJECTIVES • Define the terms: matter, elements, atoms, molecules,
compounds • Breakdown the atom’s parts and altering protons and
electrons • Physical v Chemical processes • Ions • Bonding • Chemical Oxidation of Glucose • Enzymes • Forms of Energy • Mixtures (Solutions, Suspensions, and Precipitates) • Acid Base, pH, Buffers
MATTER • “Anything that
occupies space and has weight”
• Solid, liquid, and gas
THE ATOM • Smallest
structure • Consists of: 1. Protons (+) 2. Neutrons 3. Electrons (-)
ELEMENT • “Matter that
consists of the same atoms!”
• Same number of protons!
Examples: 1. Carbon 2. Hydrogen 3. Oxygen
IONS “+ or –” • Forms when
electrons are gained or lost
• Cation = positive • Anion = negative • Electrolytes give
rise to ions
PHYSICAL & CHEMICAL REACTIONS Ø Physical process: the matter isn’t changed, just “looks
different” i. Chopping wood ii. Tearing paper in half
iii. Chewing food
Ø Chemical process: matter is changed into something else, “irreversible”
i. Burning wood
ii. Rust on a bike iii. Glycolysis
BONDS • Between two or more atoms, “connecting them together” • Atoms use electrons to make a bond • The electrons can either be “shared” or “stripped”
a) Covalent Bonds – “share electrons”
b) Ionic Bonds – “strip electrons”
COVALENT BONDS • “share
electrons” • Strong bonds,
due to sharing • Do not break
up in water! • Think oil and
water!
IONIC BONDS “Strips electrons” • One atom takes
the electron away from another atom!
• Weak bonds, break apart in water
• Think salt and water!
MOLECULE • Substance
consisting of two or more atoms!
• Example: i. H2O
ii. H2 iii. O2
COMPOUND • Substance
consisting of two or more different elements!
• Example: i. CO2
ii. C6H12O6
iii. H2O
PAY ATTENTION! ALERT: “All compounds are molecules, but not all molecules are compounds!” HUH?
For example: Water, or H2O, is a molecule because it consists of two or more atoms (one oxygen and two hydrogen = 3 atoms). H2O is also a compound; since it contains two different elements (oxygen and hydrogen)
What are some molecules that ARE NOT compounds??
CHEMICAL OXIDATION OF GLUCOSE
• Why is this important?
• This is where we get energy!
• Turning C6H12O6 (glucose) into ATP!
REACTIONS! • Atoms or elements
“interacting” and making new molecules
• Changing C6H12O6 into CO2, H2O, and ATP!
• Catalysts!
• Enzymes!
ENERGY • “the ability to do work” • ATP (energy
molecule), break to release energy
• Feel hot? A by-product of glycolysis is HEAT
4 FORMS OF ENERGY Our bodies use 4 forms of energy in order to do work: 1. Mechanical (walking, muscle contraction, running)
2. Chemical (ATP)
3. Electrical (nervous system)
4. Thermal (body temperature)
ANY QUESTIONS? INTRO TO CHEMISTRY
MIXTURES • “combinations of two or
more substances that can be separated physically”
• Two types of mixtures: 1) Solution
2) Suspension
SOLUTION • “particles that are mixed
together remain evenly distributed”
• Salt solution • Solution = solvent +
solute i. Solvent is usually H2O ii. Solute is dissolved in
solvent (can be solid, liquid, gas)
SUSPENSIONS Regular • Large particles
that will settle
• Think sand mixed with water!
Colloidal • Particles small,
don’t dissolve (like a solution) but stay suspended
• Mayo, jelly, blood
PRECIPITATES • Reaction
forming a solid
• The solid is called “precipitate”
• Kidney stones, gall stones, embolism
ACIDS AND BASES • Acid: electrolyte
that gives H+ • Base: substance
that combine with H+
• What happens when an acid combines with a base?
PH pH measures how many H+ you have • Inverse
relationship!
• Lowest pH = 0 • Highest pH = 14 • Neutral pH = 7
PH • Normal pH of
blood is 7.35 – 7.45
• Slightly what?
• Practice!
BUFFERS Resist change in pH • Either release H+ or
pick up excess H+
• Carbonic Acid – Bicarbonate buffer!
• Practice!
GROUP ACTIVITY