TAKS Objective #1

1. TAKS Objective #1 The student will demonstrate an understanding of the nature of science.

2. Safety

3. 1. Always obtain the instructor’s permission before beginning a lab.

4. 2. Read the procedure (more than once) before beginning the experiment. Ask the instructor if you have any questions.

5. 3. Always wear safety goggles.

6. 4. Always point the mouth of a test tube away from yourself and others.

7. 5. Never eat or drink anything in the lab.

8. 6. Remember if you need to smell a substance, waft it toward your nose. Do not directly smell the chemical.

9. 7. When diluting an acid, always pour the acid into the water.

10. 8. Reactions that produce toxic fumes should be performed under a fume hood.

11. 9. Know the location of all the safety equipment in the lab.

12. 10. Long hair, loose clothing, and jewelry should be secured and tied back during lab procedures.

13. 11. Do not handle hot or cold containers with your bare hands. Use the proper holder for the container.

14. 12. Report any and all accidents to the teacher immediately, no matter how big or small.

15. 13. Ask the teacher for the proper way to dispose of any material.

16. 1. A science class is conducting an experiment that produces noxious fumes. Because of inadequate ventilation, some students begin to feel nauseated and dizzy. The first response should be to — Not A – Acids are not the only producers of fumes, and adding something else could make it worse! A neutralize the acid that is reacting to produce the noxious fumes B carry the reactants outside, away from other students C leave the room and go to an area with fresh air D spray the reaction with a fire extinguisher Don’t move it anywhere except under a fume hood, Too dangerous! Not B Not D --Extinguishers should only be used on fires.

17. 2. The safest way to dilute concentrated sulfuric acid is to add — A a series of small volumes of water to the acid while stirring B the acid to water slowly while stirring constantly C the acid to a small volume of water and then add more water D dilute sulfuric acid to a small volume of the concentrated acid • The safety rule says always add acid to water, so A & C are out since they both add water to acid. • D doesn’t even make sense since you can’t make concentrated acid out of a dilute acid by adding to it. • So the answer is

18. 3. If there is a clear chemical on your table during a lab, how should you identify it? • Ask your instructor what it is. • Taste the chemical • Smell the chemical • Rub the chemical between your fingers

19. 4. You should report a cut in your skin, glass breakage, or chemical spill A. after the problem is handled B. never C. immediately D. after you write down what happened

20. 5. Which is the correct way to hold a test tube while heating its contents? A. pointing straight up B. Pointing horizontally C. Pointing away from yourself and others D. Pointing straight at yourself

21. 6. Answer: D

22. 7. Answer: A

23. Safety symbols

25. Biohazard Biological materials that could be harmful.

26. Toxic or Poisonous

27. Corrosive Corrosive means capable of destroying or eating away by chemical means.

28. Flammable Easily set on fire.

29. Safety Goggles Goggles MUST be worn at all times while in the lab.

30. Open Flame Alert Be careful when using an open flame as an explosion could occur.

31. Lab Equipment

32. Beaker • A beaker is used to hold liquids. • It is not precise enough to make good measurements.

33. Graduated Cylinder • Used to measure liquid volumes (mL). meniscus Always read a graduated cylinder from the bottom of the meniscus.

34. Pipette • Pipettes are used to measure small amounts of liquid. • They are very precise.

35. Which would be most precise? Pipette

36. Test Tube • A test tube is used to hold or store liquids. • It is not a precise measuring instrument.

37. Test Tube Rack • A test tube rack is used to hold and support test tubes.

38. Test Tube Clamp • Test tube clamps are used to hold a test tube while its contents are being heated.

39. Triple Beam Balance • A triple beam balance is used to measure mass (kg).

40. Funnel • A funnel is used to transport materials from one container into another container.

41. Erlenmeyer Flask • An Erlenmeyer flask is used to hold and mix liquids. • It is not precise.

42. Ring Stand • A ring stand is used to hold objects.

43. Bunsen Burner • A Bunsen burner uses natural gas to provide a heat source.

44. Tongs • Tongs can be used when handling hot or cold objects, such as beakers.

45. Accuracy & Precision

46. Accuracy & Precision • Accuracy = refers to how “correct” the answer is (hitting the bull’s eye) • Precision = refers to how small a scale is being used to make a measurement or how close measurements are to each other.

47. Accuracy • This is when a measurement is closest to its true value. • The exactly correct answer. • The bull’s eye.

48. Precision • This is the repeatability of a measurement. • It may or may not be accurate

49. Precise, but not accurate.

50. Accurate and precise.