What is Chemistry?

1. What is Chemistry?

2. Chemistry is… The study of all substances and the changes they undergo, central science because it overlaps many other sciences

3. Who Uses Chemistry?

4. Who Uses Chemistry? If you think the answer consists of a variety of scientists, you have a lot to learn. 

5. Who Uses Chemistry? These people all use chemistry on a daily basis… • Forensic examiners • Perfume makers • Dye makers • Medical researchers • Engineers • Biologists • Agriculture workers • Artists • Archaeologists • Ecologists • Waste water treatment workers • Cooks • Textile manufacturers • Beauticians • And many more…

6. Lab Equipment

7. Goggles Goggles are meant to protect your eyes and therefore need to be worn appropriately. If you wear glasses, you still need to wear goggles.

8. Beaker Beakers hold solids or liquids that will not release gases when reacted or are unlikely to splatter if stirred or heated.

9. Graduated Cylinder A graduated cylinder is used to measure volumes of liquids. This is a better choice for measuring volume than beakers or flasks.

10. Erlenmeyer Flask Erlenmeyer flasks hold solids or liquids that may release gases during a reaction or that are likely to splatter if stirred or heated.

11. Weighing Boat Weighing boats are used to weigh solids that will be transferred to another vessel.

12. Test Tube Racks Test tube racks are for holding and organizing test tubes on the laboratory counter.

13. Test Tubes 13 x 100 mm test tubes Ignition tube 10 x 75 mm test tubes A test tube is useful for holding liquids and for containing small chemical reactions.

14. Test Tube Holder A test tube holder is useful for holding a test tube which is too hot to handle.

15. Beaker Tongs Beaker tongs are used to move beakers containing hot liquids

16. Crucible Tongs For handling hot crucibles; also used to pick up other hot objects. NOT to be used for picking up beakers!

17. Test Tube Brushes Test tube brushes are used to clean test tubes and graduated cylinders. Forcing a large brush into a small test tube will often break the tube.

18. Rubber Stoppers Rubber stoppers are used to close containers to avoid spillage or contamination. Containers should never be heated when there is a stopper in place.

19. Spot Plates/Well Plates Spot plates are used when we want to perform many small scale reactions at one time.

20. Glass Stir Rod A glass rod is used to manually stir solutions.

21. Medicine Dropper A medicine dropper is used to transfer a small volume of liquid (less than one mL). In class, we often use disposable pipettes instead of droppers.

22. Litmus Paper Red litmus paper is used to identify bases. Blue litmus paper is used to identify acids.

23. Forceps Forceps (or tweezers) are used to pick up small objects.

24. Funnel A funnel is used to aid in the transfer of liquid from one vessel to another.

25. Wash Bottle A wash bottle has a spout that delivers a wash solution to a specific area. Distilled water is the only liquid that should be used in a wash bottle.

26. Spatulas Spatulas are used to dispense solid chemicals from their containers. Chemicals should never be transferred with your bare hands.

27. Scoopulas Scoopulas are used to dispense solid chemicals from their containers. Chemicals should never be transferred with your bare hands.

28. Strikers Strikers are used to light Bunsen burners. The flints on strikers are expensive. Do not operate the striker repeatedly just to see the sparks!

29. Bunsen Burner Bunsen burners are used for the heating of nonvolatile liquids and solids.

30. Crucible Crucibles are used for heating certain solids, to very high temperatures.

31. Clay Triangle The clay triangle is used as a support for porcelein crucibles when being heated over a Bunsen burner.

32. Ring stands and their Components Ring stands are a safe and convenient way to perform reactions that require heating using a Bunsen burner.

33. Ring stands and their ComponentsIron Rings Iron rings connect to a ringstand and provide a stable, elevated platform for the reaction.

34. Ringstands and their ComponentsUtility Clamps Utility clamps are used to secure test tubes, distillation columns, and burets to the ringstand.

35. Ringstands and their ComponentsWire Gauze Wire gauze sits on the iron ring to provide a place to stand a beaker. On older wire gauze, the white material is asbestos!

36. Lab Issues Lab Safety • Flinn contract • Broken glass bucket • Fire extinguisher • Eye wash

37. Scientific Notation Writing • Format: M x 10x • M must be less than 10 • M must be greater than or equal to 1 • x can be any whole number

38. Scientific Notation Sample Numbers to Write • 450 • 3,000,000 • 0.014 • 0.000 000 08

39. Measurement Two types of measurements • Qualitative – present regardless of amount Examples – color, taste, luster, density, etc.

40. Measurement Two types of measurements • Quantitative – based on amount Examples – mass, length, area, volume, etc.

41. Metric Units In science, we use the metric system because it is an international system (unlike the English system that is rarely used). These units have precise definitions.

42. Metric Units SI Base units • Length – meter, m • Mass – kilogram, kg • Time – second, s • Count – mole, mol • Temperature – kelvin, K Sometimes, the base units are combined to create other units

43. Measurement Derived units • Area – square meter, m2 • Volume – cubic meter, m3 • Force – newton, N • Pressure – pascal, Pa • Energy – joule, J • Power – watt, W • Voltage – volt, V • Frequency – hertz, Hz • Electric charge – coulomb, C

44. Measurement Metric Prefixes Sometimes SI units aren’t convenient for object being measured so we use metric prefixes to indicate smaller or larger units of measurement.

45. Measurement Metric Prefixes Sometimes SI units aren’t convenient for object being measured so we use metric prefixes to indicate smaller units of measurement. • mega M 1,000,000 1 x 106 • Kilo k 1,000 1 x 103 • hecto h 100 1 x 102 • deka dk 10 1 x 101 • -unit- 1 1 x 100 • deci d 0.1 1 x 10-1 • centi c 0.01 1 x 10-2 • milli m 0.001 1 x 10-3 • micro m 0.000,001 1 x 10-6 • nano n 0.000,000,001 1 x 10-9 • pico p 0.000,000,000,001 1 x 10-12

46. Measurement Metric Prefixes Sometimes SI units aren’t convenient for object being measured so we use metric prefixes to indicate smaller units of measurement. • mega M 1,000,000 106 • kilo k 1,000 103 • hecto h 100 102 • deka dk 10 101 • -base- 1 100 • deci d 0.1 10-1 • centi c 0.01 10-2 • milli m 0.001 10-3 • micro m 0.000,001 10-6 • nano n 0.000,000,001 10-9 • pico p 0.000,000,000,001 10-12 The symbols for these prefixes can be added to the beginning of any SI unit to indicate smaller or larger measurements.

47. Precision vs. Accuracy What is precision? • how well measurements agree with each other Example: 3 measurements taken of a mass give 1.00 g, 1.02 g, & 1.01 g

48. Precision vs. Accuracy What is accuracy? • how well measurements agree with an accepted standard Example: 3 measurements taken of a mass give 1.00 g, 1.02 g, & 1.01 g, accepted value = 1.01 g

49. Percent, Percent Error, Ratios How to express results… Percent = obtained × 100= _% total • May be given mixture and asked to calculate percent of one part

50. Percent, Percent Error, Ratios How to express results… Percent Example: A sample is 750 g. 400 g of that 750 g are lead. What is the percent of lead?