Chemistry of Life

Moves around nucleus 0Electron Part of nucleus 01Neutron +11Proton Location in Atom Charge Relative Mass Particles Comparison Of Particles In An Atom Atoms make up all Matter (living and nonliving)

Atoms make up ELEMENTS.

Elements make Compounds Compounds: two or more elements that are combined chemically. Compounds: two or more elements that are combined chemically. Have a formula (fixed composition) Have a formula (fixed composition) H 2 O H 2 O NaCl NaCl C 6 H 12 O 6 C 6 H 12 O 6

What is a molecule? A molecule simplest part of substance (compound) that retains all of the properties of that substance. Water (H 2 O) Oxygen (O 2 )

Water Water has several unique properties that make it one of the most important compounds found in living things! Water has several unique properties that make it one of the most important compounds found in living things! Water – molecule (2H and 1O), compound Water – molecule (2H and 1O), compound

The H and O are held together by Covalent Bond. The H and O are held together by Covalent Bond. Share electrons (strong bond) Share electrons (strong bond)

Polarity – uneven sharing/distribution of charges Polarity – uneven sharing/distribution of charges +/- ends or “poles” of water molecule +/- ends or “poles” of water molecule Oxygen pulls electrons closer, resulting in it having a partial negative charge. Oxygen pulls electrons closer, resulting in it having a partial negative charge. Hydrogen atoms then become partially positive Hydrogen atoms then become partially positive Water is POLAR. Water is POLAR. Attracted to other things with charges Attracted to other things with charges

Solutions Solubility – ability to dissolve Solubility – ability to dissolve Water is considered the “universal solvent” Water is considered the “universal solvent” Can dissolve many many substances Can dissolve many many substances Creates a “soluble” environment for cells/life. Creates a “soluble” environment for cells/life. Water’s polarity allows it to dissolve polar substances (sugar, salt) – Hydrophilic Water’s polarity allows it to dissolve polar substances (sugar, salt) – Hydrophilic Water does NOT dissolve nonpolar substances (oil, grease, fat) - Hydrophobic Water does NOT dissolve nonpolar substances (oil, grease, fat) - Hydrophobic Solvent = Substance that does the dissolving Solvent = Substance that does the dissolving Solute = Substance that is dissolved Solute = Substance that is dissolved

Cohesion Water molecule attracted to other water molecules. Due to polarity. (-)Oxygen attracts to (+) Hydrogen Opposite charges attract Hydrogen bonds hold water molecules to each other Water “clings” to itself

What holds the water together? Hydrogen bond – Holds water molecules to each other. Water is polar it’s attracted to other polar things. Weak bond. Easily broken and made.

Properties of Water Adhesion -Attractive force between two particles of DIFFERENT (unlike) substances Water attracted to something else with opposite charge Bead of water on glass

Adhesion & Cohesion

Surface Tension Created by hydrogen bonds holding water to water (cohesion). Creates “film” or tightness on surface of water Objects of relatively small mass that would normally sink can rest/sit on top of hydrogen bonds on the surface of the water.

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Surfactants lower the surface tension of water, essentially making it 'wetter' so that it is less likely to stick to itself and more likely to interact with oil and grease. Example: soaps, detergents, cleaners

Capillarity (capillary action) Liquid is allowed to be pulled upward against gravity in narrow openings/tubes. This occurs to due to cohesion, adhesion, and surface tension all working together.

Water has HIGH HEAT CAPACITY (high specific heat) Water can absorb and release large amounts of energy w/out change in temperature. The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.heattemperature Water resists change in temp – heats slowly! Why is this important? Homeostasis Buffer for body temperature Stabilizes global temp

Turgor Pressure Water pressure inside plant Turgidity –the result of the water pressure. Low turgidityHigh turgidity

Density Mass - Quantity of matter an object has. Volume - How much space an object occupies. Why do things float? Objects that are more dense will sink. Objects less dense will float. D = M/V

Why does Water in solid form (Ice) float? Angles of water molecule expand when frozen Takes up more space (volume)

Water COOLS the surface when it evaporates. (aids in homeostasis)

pH Scale The pH scale ranges from 0 to 14. The pH scale ranges from 0 to 14. Pure water would have a pH of 7 (not acidic, not basic) Pure water would have a pH of 7 (not acidic, not basic) Acids have pH less than 7; Bases have pH greater than 7. Acids have pH less than 7; Bases have pH greater than 7. pH values of most cells range from 6.5 to 7.5 pH values of most cells range from 6.5 to 7.5 ACIDIC NEUTRALBASIC More H + More OH -