intro to chemistry bio 117... · intro to chemistry chapter 2 . learning objectives • define the...

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