2. A Mad Scientist’s Chemistry Presentation CHEMISTRY TAKS

3. SCIENTIFIC METHOD Conducts lab and field work in a SAFE manner… Environmentally and Ethically sensitive Watch for questions that support unsafe practices (COMMON SENSE) Anticipate questions on disposal

4. Planning, Implementing, Collecting If given a problem, can you make a plan? What is the problem? What are possible solutions? (Hypothesis) What steps could you take to get your answers.

5. Organize, Analyze, Evaluate If given a set of facts, can you organize, analyze, and evaluate the data. Organize by “concept mapping” What is the original question? Analyze what you were given to answer the question.

6. Make Inferences Be able to read charts and determine trends. If given a brief statement, identify key points first and then relationships. Is the trend up, down, etc.? Concept mapping (THINKING MAPS) may clear the question for you.

7. Critical Thinking Steps: What is the question? What data, information is provided? Consider concept mapping. Is the question simply a “fact question” or is a conclusion called for?

8. A “fact” question… What is the density of a 15 gram sample if it occupies 5 cubic centimeters? A. 2 grams/cc B. 3 grams/cc C. 5 grams/cc D. 15 grams/cc Remember: formula sheets is provided!

9. Begin with “the question” You should be able to answer the question based on FACTS. Avoid “opinions”. An “opinion” answer on the test is USUALLY WRONG! Example: Which brand of toothpaste tastes best? TASTE is an OPINION.

10. Develop a HYPOTHESIS What do you think the answer will be? What have you seen in the past? What does your library research say? What are possible ways to answer your question?

11. Develop a procedure Write down how you will perform your test. What equipment will you need? What steps will be followed? What safety issues are involved? How will you collect and record your data?

12. Control your “variables” What is a “variable”? In this case:…. –Grain size and type of sugar –Original water temperature –Amount of tea in the mixture –Rate of stirring, etc.

13. Perform the Experiment Follow the procedures you have developed. Keep accurate records of all results AND OBSERVATIONS! USE PROPER SAFETY PROCEDURES!

14. Interpret (EVALUATE) your results What kind of results did you get? Did your results agree with your Hypothesis? If not, why not? –Did you make a mistake in your procedure? –Should you modify either your original Hypothesis or your procedure?

15. Question Example? The English physician Ronald Ross dedicated his career to the investigation of malaria and how it spread. Ross knew that a parasite called Plasmodium was always found in the blood of people infected with malaria. People had long thought that malaria was a result of breathing “bad air”. Ross, however, thought that mosquitoes spread malaria from person to person. Which of these could BEST have helped Ross determine whether mosquitoes were involved in the spread of malaria?

16. Possible Answers A. Observing wild mosquitoes for signs of malaria. B. Injecting mosquitoes with Plasmodium. C. Examining wild mosquitoes to see whether their tissues contain Plasmodium. D. Determine whether animals such as cows carry Plasmodium in their blood.

17. Selecting the BEST answer… What is Ross’s question? Are mosquitoes involved in the spread of malaria? Has he already made observations? – Yes, Plasmodium is seen in people infected by malaria. Can any be eliminated? Which answers use the same words and phrases, as the question? Now, which is the BEST answer?

18. Answer C. Examining wild mosquitoes to see whether their tissues contain Plasmodium.

19. I have several expressions and can provide additional comments for your presentation, search the Premium Gold Site for more animations of me! The Mad Scientist

20. TAKS OBJECTIVE 4 The student will demonstrate an understanding of the structure and properties of matter. – investigate and identify properties of fluids including density, viscosity, and buoyancy; –Relate the chemical behavior of element including bonding, to its placement on the periodic table; –Classify samples of matter from everyday life as being elements compounds, or mixtures

21. OBJECTIVE 4 continued Distinguish between physical and chemical changes in matter such as oxidation, digestion, changes in states, and stages in the rock cycle; Investigate and identify the law of conservation of mass Relate the structure of water to its function as the universal solvent; Relate the concentration of ions in a solution to physical and chemical properties such as pH, electrolytic behavior, and reactivity; Demonstrate how various factors influence solubility including temperature, pressure, and nature of the solute and solvent

22. WHAT IS MATTER? Anything that has matter and takes up space. –Element – building blocks of matter, cannot be broken down into simpler substances by a chemical REACTION. –Compound – made up of two or more elements that are CHEMICALLY combined. –Mixture – made up of two or more substances that can be broken down PHYSICALLY

23. THE ATOM PROTONS NEUTRON ELECTRONS ENERGY LEVEL

24. Properties of metals, nonmetals, and metalloids METAL nonmetalsMETALLOIDS shinyMostly dullVary in ability to conduct electricity MalleablebrittleUsed to make semiconductors Conduct under certain conditions ductilePoor conductors Good conductors of heat & electricity Many gases at room temperature Most are solids at room temperature

26. Valence electrons Electrons in the outermost energy level Electrons involved in bonding Li + + + s2p1s2p1 ↑↓ ↑

27. ATOM vs ION ● Ca ● Ca 2+ + 2e - Calcium atom Calcium ion 2 electrons 20 + 20 - 18 - Net chg = 0 Net chg = 2+

28. Let’s tie this into the periodic table Group number 12 13 14 15 16 17 18 # valence e-1234567 8 Gain/lose e-Lose 1 Lose 2 Lose 3 Gain/lose +4/ -4 Gain 3 Gain 2 Gain 1 0 Chg of ion +1+2+3 +4 -4 -3 -20 He: exception b/c it only has two electrons

29. Classifying matter matter Physically separated? no yes Pure substance Breakdown chemically? no element compound yes mixture Look the same? noyes heterogeneoushomogeneous solution

30. Three types of Bonds Ionic – rxn between oppositely charged particles Electrons are transferred –Covalent – nonmetals –Electrons are shared

31. What about Bonding Ionic – metal/nonmetal Or between charged ions Mn Mn 2+ S 2- S

32. IONIC BONDING Transfers electrons: Na + 2s 2 2p 6 Cl - 3s 2 3p 6

33. Covalent Bonding

34. COVALENT BONDS Examples of hydride compounds of the above elements (covalent bonds with hydrogen:

35. Covalent Bonding

36. METALLIC BONDS Force that holds atoms together in a substance. Metallic bonding is possible because in many cases the outer most electron shell of each metal atoms overlaps with a large number of neighboring atoms. It is often said they have a sea of electrons.

37. Indications of a Chemical Change 1.Change in color 2.Change in temperature 3.ppt formed 4.Formation of a gas 5.Light given off 6.New substance

38. Chemical/Physical Changes Physical change – does not change the composition –Cutting wood, melting ice, boiling water Chemical change – creates a new substance –Digestion food, grass growing

39. Now it’s your turn…. Two steel plates can be joined by a process called arc welding. In this process, tiny droplets of molten metal are deposited on the joint between the plates. The droplets then cool and harden, joining the plates together. Many metals will react with oxygen when they are exposed to the high temperatures of arc welding. Therefore, the droplets of molten metal are often shielded from oxygen in the surrounding air by a layer of argon gas. Why would argon gas be a more suitable shield for arc welding than hydrogen gas? –A. Unlike hydrogen, argon is a nonmetal –B. Unlike hydrogen, argon is an inert gas –C. Argon has a larger atomic radius than hydrogen does –D Argon has a greater atomic mass than hydrogen does.

40. Question Which best explains why sodium is more reactive than magnesium? –A. Sodium has only one valence electron, while magnesium has two –B Sodium atoms typically have one more neutron than magnesium atoms do –C Sodium forms ions with a charge of 2+, but magnesium forms ions with a charge of 1+ –D Sodium atoms tend to attract the electrons of other atoms more than magnesium atoms do

41. Question Hydrogen and nitrogen gas react in a sealed container kept at a constant temperature. The pressure in the container is less at the end of the reaction than at the beginning. 3H 2(g) + N 2(g) 2NH 3(g) – A there are fewer atoms at the end of the reaction than at the beginning. – B There are fewer molecules at the end of the reaction than at the beginning. – C The mass of the reactants is less than the mass of the products in the reaction – D The volume of the reactants is less than the volume of the products in the reaction

42. Question Scuba divers are exposed to greater pressure the deeper they dive. Which is most likely to occur as a result of this increased pressure? A. Glucose will become much more soluble in divers’ cells B A high level of nitrogen gas will dissolve in divers’ bloodstream C Small bubbles of carbon dioxide will form in divers’ bloodstream D the amount of oxygen dissolved in divers’ cells will sharply decrease

43. Good Luck! We know you will do well !!! Take your time and read the questions carefully Come by and See us for More Tutoring Prior to the Test !!