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WELCOME TO CHEMISTRY!

WELCOME TO CHEMISTRY!. Meet the Elements!. WHAT IS CHEMISTRY?. Chemistry is the study of matter and the changes that it undergoes. WHAT IS MATTER?. Matter is anything that has mass and volume.

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WELCOME TO CHEMISTRY!

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  1. WELCOME TO CHEMISTRY!

  2. Meet the Elements!

  3. WHAT IS CHEMISTRY? • Chemistry is the study of matter and the changes that it undergoes.

  4. WHAT IS MATTER? • Matter is anything that has mass and volume. • Mass refers to the measure of the amount of material in an object ( measures the resistance to an object being moved). • Volume refers to the amount of space an object occupies.

  5. MATTER HAS 4 STATES • Solid • Liquid • Gas • Plasma

  6. 3 STATES OF MATTER

  7. SOLIDS • State of matter in which the particles are closely packed. • Solids have definite shape and definite volume • Solids essentially cannot be compressed.

  8. LIQUIDS • Particles are arranged so they can slide past one another. • Liquids take the shape of their container and have definite volume. • Liquids essentially cannot be compressed.

  9. GASES • Particles are spread out widely. • Gases have neither definite shape nor definite volume. • Are very compressible.

  10. PLASMA • An electrically neutral gas of ions (charged particles) and electrons (negatively charged particles)…VERY HIGH ENERGY!! Thought to be found in stars. • Is present when nuclear fusion occurs..requires a temp of 100,000,000 0C.

  11. The smallest unit of matter is the atom • are the smallest unit of matter capable of existing by themselves. • 2 or more atoms chemically bonded together are referred to as a molecule.

  12. MODELS OF THE ATOM orbits

  13. Atoms are composed of the following subatomic particles. • Protons- Positively charged particles located in the nucleus of the atom. • Neutrons- Non-charged nuclear particles located in the nucleus of the atom. • Electrons- Negatively charged particles that move around the nucleus located in the electron cloud

  14. Matter with only one type of atom are called elements. • Each element has a unique number of protons in the nucleus of its atoms. This is what defines that particular element.

  15. ELEMENTS (CONT). • Chemists use elemental symbols as a shorthand way of representing elements. • These symbols consist of 1, 2, or 3 letters (only the 1st is uppercase). • Many elemental symbols show the Latin origin of the element’s name.

  16. Periodic Table of Elements • 114 elements • Vertical column = groups • Horizontal rows = periods • Traits are organized by similar properties

  17. ALL MATTER CAN BE CLASSIFIED AS EITHER A SUBSTANCE OR A MIXTURE • A substance is matter that has a fixed composition and distinct properties. • A mixture is a combination of 2 or more substances, each of which retains it’s properties.

  18. Substances can be either elements or compounds. • An element is a substance in which all atoms have the same number of protons. • Elements cannot be decomposed into simpler substances.

  19. Compounds • Compounds are substances in which 2 or more elements chemically combine to form a new substance with new properties. • Compounds can be decomposedinto simpler substances.

  20. COMPOUNDS CAN BE CHEMICALLY BROKEN DOWN • This can be accomplished through the use of heat energy (thermal decomposition) or electric current (electrolysis).

  21. EVERY SUBSTANCE HAS A UNIQUE SET OF PROPERTIES • Properties are characteristics that allow us to recognize and distinguish a substance from other substances.

  22. PHYSICAL PROPERTIES • Physical properties are properties that can be observed or measured without changing the identity and composition of the matter. • Physical properties include color, odor, density, melting pt., boiling pt., malleability, ductility, hardness, etc.

  23. CHEMICAL PROPERTIES • Chemical properties describe the way a substance may change or react to form other substances. • To observe this property you must carry out a chemical change. • An example would be burning in the presence of oxygen.

  24. MATTER UNDERGOES CHANGE • This may be physical change or chemical change.

  25. PHYSICAL CHANGES • In physical changes, the substance changes its physical appearance but not its composition. • An example would be changing states. • Evaporation of water into water vapor

  26. CHEMICAL CHANGES • In a chemical change, a substance is changed into 1 or more new substances with new properties. • Chemical change involves rearrangement of atoms. • Aluminum rusting, fireworks exploding

  27. PHYSICAL CHANGE

  28. INTENSIVE PROPERTIES • Are independent of sample size. • Examples include density, temperature, melting point, etc. (1 gal of water or 1 cup of water: both have same boil point.) • Can be used to identify a substance.

  29. EXTENSIVE PROPERTIES • Are properties that depend on sample size. • Examples include mass, volume, and length • 1 gal of water will have a greater mass than 1 cup of water.

  30. Mixtures can be either homogeneous or heterogeneous. • Homogeneous mixtures are uniform (have the same composition) throughout. Homogeneous mixtures are also called solutions. Ex: salt, air, water • Heterogeneous mixtures are non-uniform throughout. Ex: sand, wood, rock

  31. MIXTURES CAN BE PHYSICALLY SEPARATED • Filtration • Distillation • Chromatography

  32. FILTRATION • In filtration, the mixture is separated based on differences in particle size.

  33. DISTILLATION • Distillation separates components based on differences in boiling point.

  34. DISTILLATION APPARATUS

  35. CHROMATOGRAPHY • Separates mixture components based on differences in attraction to a surface.

  36. Name Those Molecules

  37. CHEMICAL CHANGE

  38. Measurement 1.7

  39. SCIENTIFIC DATA FALLS INTO 2 CATEGORIES • Qualitative data • Quantitative data

  40. Qualitative • Qualitative data consists of descriptiveterms. There is no use of numbers. • Determines the presence or absence of a particular substance in a mix. • Ex: water is a liquid

  41. Quantitative • Quantitative data consists of measurements (numbers) • Determines the amount of substance that is in a sample. • Water has a boiling point of 100degrees Celsius

  42. Scientific Method • Hypothesis : possible explanation of an observation. • Theory: set of tested hypothesis that give an explanation of a natural phenomena • Law: concise statement or explanation

  43. Apples, Volkswagens, Pigeons or Metric? UNITS ARE EVERYTHING! Chemistry is in the details. The slightest change or mistake can mean a world of difference. This IS going to drive you nuts this year, and you will hate chemistry, me, and the universe, but we go’tta do it!

  44. MEASUREMENT • At one time measurement was inconsistent and therefore, unreliable. • Scientists need to be able to repeat each other’s experiments to verify/modify scientific knowledge. • To assist in this process, all scientist use the SI system of measurement. (AKA your new best friend!)

  45. Base Units mass gram g length meter m time seconds s electric current ampere A temperature Kelvin K light intensity candela cd amt. Subst. mole mol l

  46. MEASUREMENT (CONT) • Scientist often use prefixes in conjunction with the basic unit of measure. • The indicate decimal fractions or multiples of various units. • Ex: milli = 10-3 1 milligram = 1 mg = 10 -3 grams

  47. Like what is a centimeter again?

  48. MEASUREMENT (CONT) PrefixSymbol Exp. Represent. Giga G 109 mega- M 106 kilo- k 103 hecto- h 102 deka- da 101 deci- d 10-1 centi- c 10-2 milli- m 10-3 micro- µ 10-6 nano- n 10-9 pico- p 10-12 MEMORIZE THIS TABLE !!!! ROYO pg 17 table 1.3

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