1. 8 th grade

2. Often brittle at room temperature and have high melting point. This is the reason they are solids at room temperature. Many are also soluble at room temperature. When mixed in water, water molecules attract each of the ions and pull the ions away from each other. This provides the ability to conduct an electrical current. Why can we get electrocuted when in a bathtub or in rain puddles? NaCl + H2O  Na + + Cl - + H2O.

3. An undissolved crystal lattice does not necessarily carry an electrical current, its only when ions are separated and allowed to move freely.

4. Covalent compounds have low solubility: They generally do not dissolve in water. Low melting points: the forces of attractions between molecules are much weaker than in ionic bonds. Remember the electrons are shared! Less heat is needed to separate the molecules of covalent compounds so they have lower melting and boiling points. When covalent compounds do dissolve in water (not many do) the solution after it is dissolved does not have a charge----for most. So there are no ions. Ex. sugar.

5. Acids: any compound that increases the number of hydronium ions when dissolved in water, H3O +. Hydrogen separates from the acid and bonds with water. Acids can cause some substances to change color. HCL + H2O  H3O + + CL -. Hydronium ions are electrolytes—which is a substance that conducts electricity. Most acids are poisonous, so don’t drink them. Tend to taste sour when tasted. Proper way to smell a liquid or substance?

6. Indicator: is something that changes color in the presence of an acid or base. Litmus, bromthymol blue, cabbage juice, phenophalene Acids do conduct electricity when dissolved in water, ions are formed----ex car battery: sulfuric acid. Where are acids used?

7. Base: any compound that increases the number of OH -, hydroxide ions, when dissolved in water. Bases have a bitter flavor and a slippery feel. Name some bases? Bases also change color in an indicator. Some bases conduct electricity when dissolved in water. Examples of bases: ammonia, fertilizers, and antacids NH3 + H2O --  NH4 + + OH - Ammonia------  ammonium

8. The concentration of an acid or base is the amount that has been dissolved in water. An acid dissolves in water and the molecules break apart and form H +, hydrogen ions. If all molecules of an acid break apart it is called a strong acid. Strong acids = strong solutions and strong electrolytes. Ex. of strong acids: sulfuric acid – H2SO4, nitric acid – HNO3, HClO4 – Perchloric acid, HCl – Hydrochloric acid, HBr – Hydrobromic acid, HI – Hydroiodic acid. If only a few break apart the acid is weak = citric and carbonic acid.

9. When all molecules of a base break apart in water Hydroxide ions, OH- are formed--it is a strong base. Strong bases form strong electrolytes and strong solutions. Ex. sodium hydroxide, calcium hydroxide, and potassium hydroxide. Group IA and Calcium, Strontium, and Barium. When only a few break apart the base is weak, ex: ammonium hydroxide and aluminum hydroxide. When acids and bases interact it is called a neutralization reaction. They neutralize one another. The H+ and OH- produce H2O—which is neutral. NaOH + HCl  NaCl + H2O

10. http://periodicvideos.com http://periodicvideos.com/videos/feature_coke_cans. htm http://periodicvideos.com/videos/feature_coke_cans. htm

11. pH scale measures the acidity or basicity of a solution. 0-6 is acidic with one being most acidic. 7 is neutral. 8- 14 is basic with 13 being most basic. Pg. 375 Seawater = 8, ammonia = 12, soft drink = 3. Lemon Juice is between a 2 and 3. Living things depend on pH staying stable. Flowers and lakes. Acid rain reacts with pollutants. Fertilizers and water. When acids neutralize a base, salt and water is formed, uses of salt, lye, sodium hydroxide—baking soda.

13. Organic compounds are covalent compounds composed of carbon-based molecules. Ex cotton, plastic, fruit, wood. Carbon backbones: organic compounds that are often composed of hundreds or thousands of carbon atoms, often combine with hydrogen, oxygen, sulfur, nitrogen, and phosphorous. Straight, branched, and ring Organic compounds that only contain hydrogen and carbon are called hydrocarbons. Propane: saturated hydrocarbon—there are single bonds Unsaturated hydrocarbon—carbons form double or triple bonds

14. Aromatic compounds are based on benzene, has a ring of six carbons that have alternating double and single bonds-- --these have strong odors. Hence—aromatic. Organic compounds that are made of living things are called biochemicals—they are divided into four categories—carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates—composed of one or more simple sugar molecules bonded together. These are used as energy, marathon runners eat a lot before running. Two types: simple and complex. 1. Simple- Sugar such as glucose 2. Complex- may be made of hundreds or thousands of sugar molecules bonded together—cellulose==========

15. Lipids- do not dissolve in water. Ex. fats, oils, wax. Store energy and function as cell walls---phospholipids Proteins- proteins most common molecule in cells after water. Composed of building blocks called amino acids. Amino acids are made of hydrogen, oxygen, and nitrogen. Enzymes are proteins---catalysts, protein in hair, DNA and RNA has protein coding. Proteins regulate chemical activities, transports and stores material, and provides structural support. Nucleic acids- made of nucleotides. Largest molecule made by living organisms. Nucleotides are made of hydrogen, oxygen, nitrogen, and phosphorous atoms. Nucleic acids store genetic information. DNA and RNA