Matter%20and%20Measure

1
Unit 1

• Matter and Measure

2
Measure
3
Scientific Measurement

• Two main systems
• English
• Based on arbitrary measurements that have lasted
  through history
• Conversions are harder to remember
• Metric
• Based on powers of ten
• Prefixes determine magnitude of power of ten

4
International System (SI)

• Scientific Community has accepted certain units
  as base units

Dimension Unit Symbol
Length Meter m
Mass Gram g
Time Second s
Temperature Kelvin K
Amount Mole mol
5
Metric System Prefixes
Prefix Power Symbol
Giga 109 G
Mega 106 M
kilo 103 k
deci 10-1 d
centi 10-2 c
milli 10-3 m
micro 10-6 µ
nano 10-9 n
pico 10-12 p
6
Measuring

• Digital Displays are recorded as is
• Digital Mass Balance, pH meter
• Visually Read Scales can always be estimated to
  smaller increment than marked
• Rulers, Thermometers, Graduated Cylinders
• Meter stick Example

7
Example

• Length??
• 0.3m 0.31m 0.314m

0m
0.4m
0.2m
0.1m
0.3m
8
Significant Figures (sigfigs)

• Not all digits(s) in a measurement are
  significant(important)
• Suppose the mass of an object is estimated to be
  2.5 grams
• The volume of that object is measured accurately
  to 0.6250000cm3
• How many decimal places should the density have?
  4.0g/cm3 or 4.000000g/cm3

9
Significant Figures (cont)

• Rules on pages 66-71 of textbook
• Shorthand
• If the decimal point is present, start counting
  digits from the Pacific (left) side, starting
  with the first non-zero digit.

? 1 2 3 0.00310 (3 sig. figs.)
10
Significant Figures (cont)

• Shorthand
• If the decimal point is absent, start counting
  digits from the Atlantic (right) side, starting
  with the first non-zero digit.

3 2 1 ? 31,400 (3 sig. figs.)
11
SigFigs for Math

• Addition and Subtraction
• Answer has to have the same number of decimal
  places as least decimal places in what you are
  adding or subtracting
• Example
• 15.62-7.248 ???
• Calculator ? 8.372
• Science ? 8.37

12
SigFigs for Math

• Multiplication and Division
• Answer has to have same number of Sigfigs as
  least number of Sigfigs in what you are
  multiplying or dividing
• Example
• 7.550.34 ???
• Calculator ? 2.567
• Science ? 2.6

13
Scientific Notation

• Short hand way of writing very large and very
  small numbers
• Uses only sigfigs
• Examples
• 602,000,000,000,000,000,000,000
• 6.02 x 1023
• 0.000000000567
• 5.67 x 10-10

14
Accuracy

• How close a measurement is to correct or accepted
  value
• Bull's-eye on a dartboard

Poor Accuracy
Good Accuracy
15
Precision

• How close a measurement is to other measurements
• Darts close to each other

Poor Precision Poor Accuracy
Good Precision Good Accuracy
Good Precision Poor Accuracy
16
Percent Error
17
Temperature

• Measure related to the heat of an object
• Measured in Celsius or Kelvin(no degrees)
• Conversion

18
Density

• Amount of matter in a given amount of space
• Amount of mass in a given volume

19
(No Transcript)
20
Matter
21
Chemistry

• What is Chemistry?
• Study of matter and the changes it undergoes
• Branches
• Organic
• Physical
• Analytical
• Biochemical
• Inorganic

22
IUPAC

• International Union of Pure and Applied Chemistry
• Group that names elements and compounds
• Meets every few years

23
Matter

• Anything that has mass and takes up space, volume
• Classified into two categories
• Substances (Pure)
• Mixtures

24
Atom

• Simplest form of matter
• Made up of Subatomic Particles
• Different atoms have different properties

25
Pure Substances

• Element
• simplest form of matter that has a unique set of
  properties.
• arranged into a table, called the periodic table
• Cant be broken down by chemical means
• denoted using chemical symbols, O, Cu, Fe
• Symbols always have the first letter capitalized
• If needed, any additional letters are not
  capitalized

26
Pure Substances (Cont)

• Compounds
• substance of two or more elements chemically
  combined in a fixed proportion
• Ex. H2O, C6H12O6
• Can be broken down by chemical means

27
Mixtures

• Physical blend of two or more substances
• Two Types
• Homogeneous
• Heterogeneous

28
Mixtures (cont)

• Homogeneous
• Composition is uniform throughout
• Examples Air, Olive Oil, Stainless Steel
• Solution is a homogeneous mixture
• Aqueous Solution is something mixed in water
• Heterogeneous
• Composition is not uniform throughout
• Examples Salad Dressing, Chicken Noodle Soup

29
Separating Mixtures

• Differences in physical properties can be used to
  separate mixtures
• Filtration Separates solids from liquids in
  heterogeneous mixtures
• Distillation Separates homogeneous liquid
  mixtures based on different boiling points

30
Separating Mixtures

• Evaporation evaporate away liquid to leave
  solid
• Chromatography separation of substances based
  on polarity

31
Phases(States) of Matter

• Solid
• Definite shape and volume
• Particles are packed tightly together in a
  regular geometric pattern
• (s) used after chemical formulas
• Cu(s)

32
Phases of Matter

• Liquid
• Definite volume, takes shape of container
• Particles can slide past each other
• (l) used after chemical formulas
• H2O(l)

33
Phases of Matter

• Gas
• Takes shape and volume of container
• Particles are spread very far apart
• (g) used after chemical formulas
• H2O(g)

34
Aqueous Solutions

• Dissolved in water
• (aq) used after chemical symbols
• NaCl(aq)

35
Phase Changes

• Solid ? Liquid Melting
• Liquid ? Solid Freezing
• Liquid ? Gas Vaporization
• Gas ? Liquid Condensation
• Solid ? Gas Sublimation
• Gas ? Solid Deposition
• Temperature does NOT change during a phase change

36
Identifying Substances

• Physical Property
• quality or condition of a substance that can be
  observed or measured without changing the
  substances composition
• Ex Color, shape, size, mass
• Physical Change
• some properties change, but the composition
  remains the same
• Can be reversible or irreversible
• Ex melting, freezing, tearing

37
Identifying Substances (cont)

• Chemical Change
• change that produces matter with a different
  composition than the original matter
• Ex. burning, rusting, decomposing, exploding,
  corroding
• Chemical property
• property that can only be observed by changing
  the composition of the substance.
• Ex Reactivity with acids, reactivity with oxygen

38
Physical or Chemical ?

• Boiling Point Physical
• Green color Physical
• Shiny Physical
• Conductivity Physical
• Solubility Physical
• Reacts with acid Chemical
• Reacts with O2 Chemical

39
Energy

• Capacity to do work
• Ability to do something
• Types
• Chemical
• Electrical
• Mechanical
• Potential
• Kinetic

40
Energy Exchanges

• Exothermic
• Process when energy is released or given off
• Ex Burning, freezing
• Endothermic
• Process when energy is absorbed or taken in
• Ex Melting

41
Scientific Method

• Observation
• using five senses to make observations.
• Hypothesis
• proposed explanation for an observation.
• Experiment
• procedure used to test a hypothesis.

42
Scientific Method (cont)

• Analyze Data
• check to see if results support hypothesis.
• Theory
• well tested explanation for a broad set of
  observations.
• Law
• concise statement that summarizes the results of
  many observations and experiments.

43
Scientific Laws

• Law of Conservation of Mass
• Mass can not be created or destroyed, only
  changed into different forms
• Law of Conservation of Energy
• Energy can not be created or destroyed, only
  changed into different forms