Chapter 2: Chemistry

What is matter made up of and how does it react?

What is Matter?

• Anything that occupies space and has mass.

Elements

• Pure substance made up of only one kind of atom

• 90 occur naturally

• 25 essential to life: O, C, H, N– 0= 65%, C=18.5%, H=9.5%, N=3.2%

• Atom: smallest unit of matter that cannot be broken down by chemical means.

Periodic Table

• Atomic Symbol: C = carbon, or Au = gold

• Atomic Number: Number of Protons in an Atom. Carbon has ? Gold has ?

• Atomic Mass: Number of Protons and Neutrons.

• Isotope: Different numbers of Neutrons than Protons

Periodic Table

Atoms

• Three major parts. – Protons: Positive Charge. Inside Nucleus

– Neutrons: Neutral Charge. Inside Nucleus:

– Electrons: Negative Charge. Outside Nucleus• 2 electrons in first shell• 8 electrons in the second shell• Eight is Great! Will not React with other

atoms.• If the outer shell is not full it will react.

Combining Chemicals

• Compound: When two or more different elements combine.

• Hydrogen Bond: H2O – When hydrogen bonds with another atom. Creates a

polar molecule.• Covalent bond: CO2

– When atoms on the same side of the chart (same size) bond. Share electrons.

• Both Hydrogen and Covalent bonds form molecules, ionic bonds do not.

Ionic/ Covalent

Bonds

Periodic Table

Bonding

Combining Chemicals continued

• Ionic Bonds: When atoms on different sides of the chart (different size) bond. Steal electrons. Create Ions. Make teeth and bones.

• Ion: Charged particle either negative or positive. NaCl = table salt

• Free Radical: Electrically charged ion with an unpaired electron in its outer shell.

Antioxidants, What are they?

• Subatances that inactivate oxygenderived free-radicals

• Slows damage from free-radicals

• Examples: Selenium, Zinc Beta-carotene, Viamins C & E

Acai Berry

Free Radicals

Energy and Chemical Reactions

• Reactants and Products– Co2 + H20 = H2C03

• Energy Transfer– Exergonic Rxns- Energy exits or released– Endergonic Rxns- Net absorption of energy

• Activation energy– Energy needed to start the reaction. Catalysts

reduce the energy needed. Often enzymes.

More on Ionic Bonds

• Ionic Bonds have 2 parts– Cation: Positively Charge, Ca+2

• Has lost 2 electrons

– Anion: Negatively Charged, Cl-• Has Gained to electrons

• Electrolytes: Ionic compounds that breaak into cations and anions when dissolved. (Salt)

Solution

• A mixture in which one or more substances are evenly distributed in another substance.

• Solute: smaller word, smaller thing

• Solvent: bigger word, bigger thing

The Importance of Water

• Polar molecule (it has a negative and positive charge.)– Can dissolve both Ionic and Polar-Covalent

molecules

• Surface Tension– Cohesion: Sticks to itself.– Adhesion: Like a band-aid. Sticks to stuff

• Capillary Action: Climbs up thin tubes

Importance of Water: an inorganic compound

Importance of Water: an inorganic compound

• Evaporates: Cooling, Water cycle, etc

• Resists Temperature Change: Takes a lot of energy to heat or cool water

• Expands as it Freezes.

Ph Scale• Measured on grams of Hydrogen (H+)

– pH of 1= 1g of H+, pH of 2= .01g of H+

• Acid: form hydronium ions (H+)– pH of less than 7 ( 1 to 6.9)

• Base: form hydroxide ions (OH-)– pH of more than 7 (7.1 to 14)

• Acid + Base: salt & water, the solution is neutral with a pH of 7. – NaOH + HCL = H2O + NaCl with a pH of 7

What is a Buffer?

• Chemical substances that neutralizes small amounts of an acid or base added to a solution.

• Why are these important to your body?

Organic Compounds: C-H

• Carbohydrate: fast energy– made of Carbon, Hydrogen, and

Oxygen. 1:2:1 proportion. Sacchar = sugar• Monosaccharides:C6H12O6, glucose and fructose

• Disaccharides: 2 sacchar’s: Sucrose, table sugar

• Polysaccharides: Many sacchar’s: Cellulose (wood) and starch.

Carbohydrates

Organic Compounds: C-H

• Lipids: Fats long term energy storage

–Have very few oxygen atoms

–Saturated fats: All C bonded to H. Lard, and butter.

–Unsaturated fats: C is double bonded to itself. Oil.

Lipids

Organic Compounds:All organic compounds contain Carbon.

• Protein: the working molecule – 50 or more Amino Acids make a

protein

– Types of Proteins• Muscle

• Enzymes: Control chemical reactions and can be re-used like a key in a lock

• Hair

Protein

Organic Compounds:All organic compounds contain Carbon.

• Nucleic Acids: pg. 37 DNA and RNA

–Made of nucleotides: Sugar, Phosphate, and X

• ATP: energy cells run on.

DNA