1 / 52

Chapter 1 Matter & Measurement

Chapter 1 Matter & Measurement. Chemistry is…. …the study of the composition, structure, and properties of matter and the changes it undergoes. C 2 H 5 OH + 3 O 2  2 CO 2 + 3 H 2 O + Energy. Reactants  Products. Matter. Anything that has mass and occupies space.

ashton
Download Presentation

Chapter 1 Matter & Measurement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 1 Matter & Measurement

  2. Chemistry is… …the study of the composition, structure, and properties of matter and the changes it undergoes C2H5OH+3O2 2 CO2 + 3 H2O + Energy Reactants  Products

  3. Matter Anything that has mass and occupies space Mass A measure of the amount of matter

  4. Atom The smallest unit of an element that maintains the properties of that element Element A pure substance made of only one kind of atom

  5. Properties of Matter Extensive properties depend on the amount of matter that is present. Volume Mass Energy Content (think Calories!) Intensive properties do not depend on the amount of matter present. Melting point Boiling point Density

  6. Physical Change A change in a substance that does not involve a change in the identity of the substance. Example: Phase Changes

  7. Phase Differences Solid – definite volume and shape; particles packed in fixed positions. Liquid– definite volume but indefinite shape; particles close together but not in fixed positions Gas– neither definite volume nor definite shape; particles are at great distances from one another Plasma – high temperature, ionized phase of matter as found on the sun.

  8. Three Phases

  9. Copper Phases - Solid

  10. Copper Phases - Liquid

  11. Copper Phases – Vapor (gas)

  12. Chemical Change A change in which one or more substances are converted into different substances. Heat and light are often evidence of a chemical change.

  13. Separation of a Mixture The constituents of the mixture retain their identity and may be separated by physical means.

  14. Separation of a Mixture The components of dyes such as ink may be separated by paper chromatography.

  15. Filtration:

  16. Separation of a Mixture Distillation

  17. Separation of a CompoundThe Electrolysis of water Compounds must be separated by chemical means. With the application of electricity, water can be separated into its elements Reactant  Products Water  Hydrogen + Oxygen H2O  H2 + O2

  18. Measurement

  19. Nature of Measurement Measurement - quantitative observation consisting of 2 parts Part 1 - number Part 2 - scale (unit) • Examples: • 20grams • 6.63 x 10-34Joule seconds

  20. The Fundamental SI Units(le Système International, SI)

  21. SI PrefixesCommon to Chemistry

  22. Temperature Scales

  23. The Thermometer • Determine the temperature by reading the scale on the thermometer at eye level. • Read the temperature by using all certain digits and one uncertain digit. • Certain digits are determined from the calibration marks on the thermometer. • The uncertain digit (the last digit of the reading) is estimated. • On most thermometers encountered in a general chemistry lab, the tenths place is the uncertain digit.

  24. Do not allow the tip to touch the walls or the bottom of the flask. If the thermometer bulb touches the flask, the temperature of the glass will be measured instead of the temperature of the solution. Readings may be incorrect, particularly if the flask is on a hotplate or in an ice bath.

  25. Reading the Thermometer Determine the readings as shown below on Celsius thermometers: 8 7 4 3 5 0 _ _ . _ C _ _ . _ C

  26. Volume Instruments

  27. Reading the Meniscus Always read volume from the bottom of the meniscus. The meniscus is the curved surface of a liquid in a narrow cylindrical container.

  28. Try to avoid parallax errors. Parallaxerrors arise when a meniscus or needle is viewed from an angle rather than from straight-on at eye level. Correct: Viewing the meniscusat eye level Incorrect: viewing the meniscusfrom an angle

  29. Measuring Volume • Determine the volume contained in a graduated cylinder by reading the bottom of the meniscus at eye level. • Read the volume using all certaindigits and one uncertain digit. • Certaindigits are determined from the calibration marks on the cylinder. • The uncertain digit (the last digit of the reading) is estimated.

  30. Use the graduations to find all certain digits There are two unlabeled graduations below the meniscus, and each graduation represents 1 mL, so the certain digits of the reading are… 52 mL.

  31. Estimate the uncertain digit and take a reading The meniscus is about eight tenths of the way to the next graduation, so the final digit in the reading is . 0.8 mL The volume in the graduated cylinder is 52.8 mL.

  32. 10 mL Graduate What is the volume of liquid in the graduate? 6 6 _ . _ _mL 2

  33. Uncertainty in Measurement • A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.

  34. Why Is there Uncertainty? • Measurements are performed with instruments • No instrument can read to an infinite number of decimal places Which of these balances has the greatest uncertainty in measurement?

  35. Precision and Accuracy • Accuracyrefers to the agreement of a particular value with the truevalue. • Precisionrefers to the degree of agreement among several measurements made in the same manner. Precise but not accurate Precise AND accurate Neither accurate nor precise

  36. Significant Digits: Atlantic/ Pacific Rule • Atlantic - • When the decimal is ABSENT, go to the Atlantic side of the number, start counting digits when you reach a non-zero number. Record

  37. 45,000 hrs 78,700 kilometers 3,000 liters two three one Practice

  38. Pacific - when the decimal is PRESENT, go to the Pacific side of the number, start counting digits when you reach a non-zero number

  39. .009999 grams 560.03 mL 100.0 meters .00506 4 5 4 none Practice

  40. Rules for Counting Significant Figures - Details • Nonzero integersalways count as significant figures. • 3456has • 4sig figs.

  41. Rules for Counting Significant Figures - Details • Zeros • -Captive zeros always count as significant figures. • 16.07 has • 4 sig figs.

  42. 56,000,000 seconds 33,000 candles 60900 milligrams .899000 centimeters .6700 meters 2 0 * 3 6 4 More practice

  43. Sig Fig Practice #1 How many significant figures in each of the following? 1.0070 m  5 sig figs 17.10 kg  4 sig figs 100,890 L  5 sig figs 3.29 x 103 s  3 sig figs 0.0054 cm  2 sig figs 3,200,000  2 sig figs

  44. Density – a derived measurevalue is found through mathematical computation D=Mass/ Volume

  45. Scientific Notation In science, we deal with some very LARGE numbers: 1 mole = 602000000000000000000000 In science, we deal with some very SMALL numbers: Mass of an electron = 0.000000000000000000000000000000091 kg

  46. . 2 500 000 000 9 7 6 5 4 3 2 1 8 Step #1: Insert an understood decimal point Step #2: Decide where the decimal must end up so that one number is to its left Step #3: Count how many places you bounce the decimal point Step #4: Re-write in the form M x 10n

  47. 2.5 x 109 The exponent is the number of places we moved the decimal.

More Related