Chemistry of Life

What is an element? How about an atom??? What is Matter? Anything that has mass and takes up space What is an element? A substance that cannot be further broken down How about an atom???

What are the most common elements of life? Trace elements?

Symptom of an iodine deficiency Iron deficiency? Fluoride deficiency

Locations and charges of protons? Neutrons? Electrons?

Arrangement of electrons in the electron shells

Atomic number = number of protons in an atom Atomic mass = number of protons + number of neutrons

What makes an atom stable???

If an atoms outer electron shell is not full it will react with other atoms (form bonds) in order to fill it Diagram showing how two hydrogen atoms share a pair of electrons so that each has a filled outer shell *** COVALENT BOND Molecular formula (shows how many atoms of each element are present in the molecule) Structural formula shows how the different atoms are connected the solid line connecting 2 atoms indicates a covalent bond

Ionic Bond

isotopes

pH …. What do you know about this?

(Higher concentration of H+) (Lower concentration of H+) pH scale 1 Battery acid 2 Lemon juice, gastric juice 3 Grapefruit juice, soft drink, vinegar, beer (Higher concentration of H+) Increasingly ACIDIC Acidic solution 4 Tomato juice 5 Rain water 6 Human urine Saliva NEUTRAL [H+]=OH–] 7 Pure water Human blood, tears 8 Seawater Neutral solution 9 Figure 2.15 The pH scale represents the relative concentration of H+ and OH–. 10 (Lower concentration of H+) Increasingly BASIC Milk of magnesia 11 Household ammonia 12 Household bleach 13 Oven cleaner Basic solution 14

Figure 2.15 The pH scale represents the relative concentration of H+ and OH–.

Why is pH important? Different areas of the body have different pH values Ex: stomach blood If the pH varies from this value, proteins lose their shape and don’t work Role of buffers in the body Keep the pH in a narrow range (keep pH values steady)

Water Electrons are shared, but not shared equally -spend more time around the Oxygen -form a POLAR COVALENT bond (–) O Figure 2.9 A water molecule. H H (+) (+)

Hydrogen bond Figure 2.10 Hydrogen bonds between water molecules.

pH In pure water, some water molecules split apart forming hydrogen ions (H+) hydroxide ions (OH–) Teaching Tips 1. Discussions of pH are enhanced by lab activities that permit students to test the pH of everyday items (foods and household solutions). If students do not have opportunities to conduct such tests in labs, consider testing a few items during your class (pH paper or a basic pH meter will, of course, be necessary). If the water is pure then the amounts of hydrogen ions (H+) is equal to the amounts of hydroxide ions (OH-)

pH If something is added to pure water to disrupt this equality, the substance is an acid or a base Acids Have more H+ than OH- Bases Have more OH- than H+ Teaching Tips 1. Discussions of pH are enhanced by lab activities that permit students to test the pH of everyday items (foods and household solutions). If students do not have opportunities to conduct such tests in labs, consider testing a few items during your class (pH paper or a basic pH meter will, of course, be necessary).

A pH scale is used to describe whether a solution is acidic or basic pH ranges from 0 (most acidic) to 14 (most basic) A solution that is neither acidic or basic is neutral (pH = 7) Teaching Tips 1. Discussions of pH are enhanced by lab activities that permit students to test the pH of everyday items (foods and household solutions). If students do not have opportunities to conduct such tests in labs, consider testing a few items during your class (pH paper or a basic pH meter will, of course, be necessary).

Cohesion of water  water sticking to itself Does this because of hydrogen bonding Results in water having surface tension “film” on top of water

Temperature moderation Water resists changes in temperature Water can absorb and release a lot of heat energy with a small change in temperature

Absorbs a lot of energy when heating up Releases energy when cooling down

Adhesion  water sticking to something else Meniscus

Transpiration Uses cohesion and adhesion to move water from the roots to top of a tree

Adhesion of water To cells of xylem Cohesion of water to itself

Density Water is densest at 4℃ Ice is less dense than liquid water Provides insulation and allows wildlife to survive under a layer of ice

Water is an almost universal solvent In a solution the SOLVENT is the substance in a greater amount The SOLUTE is the substance present in a lesser amount Ionic compounds (like salt) will dissolve in water Polar molecules will dissolve in water (sugar)

Glucose

Ionic Bond Occur when atoms gain or lose electrons, forming ions Form ions to have outer electron shell full Ions of opposite charges attract

What is an isotope?

Isotopes use to diagnose disease Cancerous throat tissue

                                                        The illustration shows the concentration of radioactive tracer bound to monoamine oxidase B (MAO B). Red shows the highest concentration. MAO B is important because it breaks down the chemicals that allow nerve cells to communicate and regulate blood pressure.

Buffers Molecules that can accept or release H+ resist change in pH Are usually weak acid/base pairs

Organic Chemistry

Hydrocarbons