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CHAPTER 1 AP CHEMISTRY

CHAPTER 1 AP CHEMISTRY. TYPES OF MATTER. PURE SUBSTANCE the same throughout ELEMENTS Fixed properties, substance cannot be broken down chemically COMPOUNDS

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CHAPTER 1 AP CHEMISTRY

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  1. CHAPTER 1 AP CHEMISTRY

  2. TYPES OF MATTER • PURE SUBSTANCE • the same throughout • ELEMENTS • Fixed properties, substance cannot be broken down chemically • COMPOUNDS • Two or more elements chemically bonded, fixed properties, can be broken down chemically

  3. PHYSICAL PROPERTIES/CHANGES • Properties • Can be measured and will usually be the same • Color, density, boiling point, melting point, hardness • Change • Properties remain the same throughout a physical change • Phase change • Solid, liquid, gas • Mass or volume change

  4. CHEMICAL PROPERTIES/CHANGES • Properties • The way a substance reacts with another substance • Changes • Identity of the substance is altered

  5. MIXTURES • HOMOGENEOUS • Uniformly mixed, all in the same phase • HETEROGENEOUS • Not uniformly mixed, different phases • CAN BE SEPERATED BY PHYSICAL MEANS

  6. MEASUREMENTS PAGE 8 • LENGTH • BASIC UNIT - METER • 1m = 102 cm = 10-3km • 1nm = 10-6 mm = 10-9 m • Common unit prefixes - kilo, centi, milli, nano • MASS • BASIC UNIT KILOGRAM • COMMON PREFIXES • Kilo, milli, mega

  7. TEMPERATURE • UNIT • CELSIUS - oC • FAHRENHEIT - OF • KELVIN - K • Temperature is the factor that determines the direction of heat flow • Temperature is measured indirectly by measuring its effect upon the properties of a substance

  8. RELATIONSHIP BETWEEN CELSIUS AND FAHRENHEIT • Celsius and Fahrenheit when compared to each other form a linear line • y = mx + b B = y when x is 0 • m = y2 - y1 Tf = Tc(9oF/5oC) + 32 x2 - x1 • Boiling and melting points

  9. CELSIUS AND KELVIN • Kelvin is known as the absolute scale, used in chemistry • 0K = -273.15 oC • TK = TC + 273.15

  10. ENERGY • SI unit is Joule • 1J = 1 N.m = 1 kg.m2/s2 • Relationship between calories and Joules • 1cal = 4.184 J • PROPERTIES • INTENSIVE • The value is not dependent on the amount of material you have • EXTENSIVE • Depends on the amount

  11. UNCERTAINITY IN MEASUREMENTS • Every measurement has a degree of uncertainty. Human error or balances that are calibrated differently. • ACCURATE • How close the measurements are to the “true” value • PRECISION • How close an individual measurement is to other measurements

  12. precision and accuracy

  13. DERIVED UNITS • VOLUME • SI unit is m3 • 1cm3 = (10-2 m)3 = 10-6 m3 • 1L = 1000 mL =1000 cm3 • FORCE • SI unit is Newton • 1N = 1kg.1m/s2 • PRESSURE • SI unit is Pascal • 1Pa = 1N/m2 • Standard atmosphere is 1.013 x 105 Pa

  14. SIGNIFICANT FIGURES • ATLANTIC-PACIFIC RULE • If a decimal point is Present then count the significant figures from the left (Pacific side). Start with the first nonzero number ----> 0.07302 • If a decimal point is Absent then count the significant figures from the right (Atlantic side). Start with the first nonzero number 40978000 <-

  15. SIGNIFICANT FIGURES • State of degree of confidence in the measurement cited • Nonzero integers: • Nonzero integers are always significant • Zero’s. There are three classes or zero’s • Leading zero’s precede (before) all nonzero digits. ARE NOT SIGNIFICANT 0.0025 • Captive zero’s are between two nonzero digits. ARE SIGNIFICANT 1.109 • Trailing zero’s are to the right of nonzero integers. ONLY SIGNIFICANT IF A DECIMAL POINT IS PRESENT 57000 and 57000.

  16. ROUNDING NUMBERS • In a series of calculations carry all digits unit the final solution, THEN ROUND • If a digit needs to be rounded • If it is less than 5, the preceding digit remains the same • If the digits are equals or is greater than 5, the preceding digit is increased by one.

  17. UNCERTAINITY IN NUMBERS • Multiplication and division • Significant figures are the same as the least precise (number with the smallest number of significant figures) measurements • Addition and subtraction • The answer will have the same number of digits beyond the decimal point as the integer (that was added or subtracted) with the least accurate number (last significant number is in the highest place holder)

  18. PERCENT ERROR • When doing an experiment it is important to see if you did it correctly. This can be done if an accepted value is known. (i.e. density of copper 8.9 g/mL). You compare your value to the accepted value by using percent error • Percent = │accepted value - experiment value│ x 100 Error accepted value

  19. DENSITY, MELTING AND BOILING POINTS • DENSITY • Mass/volume, unit = g/cm3 • Melting point • Temperature at which solid goes to liquid phase • Boiling point • Temperature at which liquid goes to gas • Solubility • Different compounds have different solubility's at different temperatures • Usually solubility of a solid goes down as the temperature goes down (except KOH)

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