Transcript CHM 115 matter measurement and problem solving part 1x

Matter Measurement and
Problem Solving
Atoms and Molecules, Inquiry, Classification of Matter,
and physical and chemical changes
What is chemistry?
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Studies matter,
including changes
involving matter and
energy accompanying
the change
The science that
seeks to understand
behavior of matter by
studying behavior of
atoms and molecules
What is matter?
Universe
Matter
Has massAmount of
matter
Occupies volume
Energy
Further classified
by state and/ or
purity
No mass or
volume
Ability to
produce change
Further classified
by type of change
(heat, work, etc.)
Atoms vs. Molecules
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Atom
◦ Most basic unit of matter
◦ Fundamental particles that are the building
blocks of ordinary matter
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Molecule
◦ Atoms are typically not in isolation
◦ Group of atoms that are held together by
chemical bonds
Scientific Method
Variables
Math is used in every step of the scientific
method- it is a tool of science
 Independent variable- x axis (set value)
 Dependent variable- y axis (responds to
changes in x)
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Experiment
Allows determination of cause and effect
 Expressed as math relationship or graph

Determining Scientific Theory
One or more well-established
hypotheses may form basis for
scientific theory
Scientific Theory vs. Scientific Law
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Theory- Well tested hypothesis
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Best explanation/ model
General
Can be used to predict
Validated by experimentation but can never be
conclusively proven
Scientific Law – General summary of related
observations
◦ Often in form of math relationship
◦ Subject to further verification by experiment
◦ NOTE- scientific law can be proven invalid by new
data. (e.g. Law of Conservation of Mass invalid for
nuclear reactions)
Properties of Matter
Observable, measureable characteristics
 Use to describe, classify, and identify
 Expressed as either qualitative or
quantitative

Physical States of Matter
Types of Solids
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Crystalline Solid
◦ Atoms or molecules
are arranged in
repeating patterns
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Amorphous Solid
◦ Atoms or molecules
do not have any long
range order
Qualitative vs. Quantitative
◦ Qualitative
 Estimated
 No measuring device
needed
◦ Quantitative
 Value + appropriate
units
 Need to use measuring
device/ instrument
Quantitative Properties
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Reliable measurements need…
◦ Proper selection, use of measurement device
◦ Appropriate set of units (metrics/ SI units)
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Scientific Notation
◦ Ability to compactly express large and small
numbers
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Dimensional Analysis
◦ Convert units as necessary
◦ Factor- label, unit factor
Intensive vs. Extensive properties
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Intensive Properties
◦ Do not depend on size, extent, amount
◦ Only depend on identity, purity and conditions of
measurement (temperature, pressure)
◦ Not additive
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Extensive Properties
◦ DO depend on the amount
◦ Are additive
◦ Different materials can have same value
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Properties are EITHER intensive or extensive,
not both
Intensive vs. Extensive
Intensive or Extensive?
Color
Odor
Mass
Weight
Malleability
Volume
Melting or freezing point
Density
Hardness
Length
Conductivity
Types of Matter
 Pure
Substances
◦ Substance made of a single type of atom
or molecule
◦ Broken into elements and compounds
 Elements- substance that cannot be broken
into simpler substances
 Compound- substance composed of two or
more substances
Types of Matter
 Mixtures
◦ Combination of two or more pure
substances
 Homogeneous
 Two or more substances mixed with same
composition
 Solution
 Does not settle out over time
 Heterogeneous
 Two or more pure substances with varied
composition
 Does settle out over time
 Colloids and suspensions
Classification of Matter
Classification of Matter Practice
Element, Compound, Heterogeneous Mixture or Homogeneous Mixture
Jello
Mint chocolate chip ice cream
Chicken noodle soup
Helium
Water
Diamond
Tea
Iced tea
Sour cream
Peanut butter
Sodium chloride
Carbon dioxide
Oxygen
Physical and Chemical Changes
Physical Change
Chemical Change
Physical Property
Chemical property
Alters only state or
appearance
Atoms rearrange
into different
substance
Extensive Property
Intensive Property
Changes back easily
Needs chemical
reaction to change
back
Still considered same
thing afterwards
No longer
considered original
substance
Physical or Chemical Change?
Butter melting
Wood rotting
Melting gold
Grating cheese
Turning sugar to caramel
Nail rusting
Digesting food
Lighting a stove
Tearing paper