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CHAPTER 1Matter, Energy and Change
What is Chemistry? 1. Is a physical science: looks at
nonliving things (rocks, stars, electricity)
2. Is the study of the composition, structure, and properties of substances and the changes they undergo
What is a chemical? 1. A substance produced by or
used in a chemical process
2. A undesirable substance (pollution, poisonings)
3. A desirable substance (cure diseases, maintain food
supply)
Branches of Chemistry 1. Organic chemistry: the study of
substances containing carbon and hydrogen, and their derivatives
2. Inorganic chemistry: the study of all substances not classified as organic chemicals
3. Physical chemistry: the study of the properties, transformations and interrelationships of
energy and matter
4. Biochemistry: the study of all substances and processes
that occur in livings things
5. Analytical chemistry: the identification of substances
and the qualitative and quantitative determination of the composition of materials
The Scientific Method 1. The goal is to solve a problem or
answer a questions
2. The ultimate goal is to explain and predict natural phenomena
3. Is defined as a logical approach to the solution of problems that lend themselves to investigations by observing, generalizing, theorizing, and testing
Steps: 1. Observation All the information you can
gather through the use of your five senses.
2. Question Sometimes the question
come before observation.
3. Hypothesis Can never be a question,
but a possible answer to the question which
started the entire process.
4. Experiment Data is gathered,
recorded, analyzed in order to insure an accurate conclusion.
5. Conclusion Are the results of
experimentation and may raise new questions and lead to new hypothesis and new reasons for further experimentation.
6. Natural Law Describes HOW nature
behaves.
7. Theory Explains why nature behaves
in the way described by the natural law.
Explains the original question and other questions that may have happened along the way.
Also predicts the results of further experiments dealing with the question.
Matter and Energy 1. Matter: anything that has
mass and takes up space
So what does not have mass and takes up space?
energy
2. Other definitions: a. Inertia: the resistance to
change in motion
b. Weight: the measure of the earth’s gravitational attraction for matter
c. Mass: the measure of the quantity of matter
3. The Law of conservation of mass
a. Matter cannot be created or destroyed in ordinary chemical or physical changes
b. It simply changes shape or form
Definition of energy 1. The ability to cause change or
the ability to do work
2. Two types a. Kinetic energy: energy in
motion
b. Potential energy: energy an object has because of its
position or composition
Energy labels a. Chemical energy
b. Mechanical energy
c. Electrical energy
d. Radiant energy
Law of Conservation of Energy
“ Energy can not be created nor destroyed in ordinary chemical or physical means. It simply changes form.”
States of Matter 1. solid: definite shape and
volume 2. liquid: definite volume, ability
to flow and to take the shape of the container
3. gaseous: neither definite shape or volume
4. plasma: gaseous system composed of positively-charged
particles and negatively-charged electrons
solid liquid gas
plasma
Properties and Changes in Matter Properties: Characteristics that enables
us to distinguish one kind of matter from another
Physical properties: 1) Can be observed or
measured without altering the identity of a material
2) Described as qualitatively (large, small, few, many)
3) Described as quantitatively ( 5 cm long, 20 pieces of Al)
4) Extensive: depends on amount of matter present (mass, length, volume)
5) Intensive: does not depend on amount of matter
(melting, freezing, boiling point, density, ductility,
malleability, color , crystalline shape, refractive index)
Physical change: A change in the property of
matter that does not result in a change in identity.
Ex. Cutting, smaching, change in state
change in state: g l s
Chemical properties: Ability of a substance to undergo
a change that alters its identity
Ex. Burning, rusting, molding
Chemical change (chemical reaction)
Any change in which one or more substances are converted into different substances with new identities
reactants products
sodium + chloride sodium chloride
Indications of chemical reactions 1. heat and light
2. production of a gas
3. formation of a precipitate
precipitate: a solid that separates from a solution
Energy and changes in matter 1. Exothermic: a process that
releases heat
Ex. Water (l) ice (s) + heat
2. Endothermic: a process that
absorbs heat
Ex. Ice (s) + heat water (l)
Classification of matter 1. Mixtures A combination of two or
more kinds of matter, each keep their own identities
a. Heterogeneous mixture: the composition and properties are not uniform, they differ from one point to another
phases: same physical properties
and chemical properties
Ex. Ice and water (both H2O)
b. Homogeneous mixtures: The composition and
properties are uniform throughout the
mixture
also called solutions can be separated
What are the following mixture?1. Sugar water2. Vegetable soup3. Brass4. Granite5. Notebook paper6. Pencil lead
Pure Substances: A homogeneous sample of
matter that has the same composition and properties, whatever the source.
Ex. Water, sugar, oxygen, silver, graphite and lead
Pure substances differ from mixtures: 1. Every sample of a given pure
substance has exactly the same characteristic properties.
2. Every sample of a given pure substance has exactly the same composition.
3. A pure substance cannot be separated into other substances without changing its identity and properties.
Pure substances continued:Elements and compounds
Element: a pure substance that cannot be decomposed
by ordinary chemical change
ex. Calcium, oxygen, chlorine
Chemical compound: A pure substance that can be
decomposed into two or more simpler substances by a chemical change.
Ex. H2O, NaCl, HC2H3O2
All matter
(Yes) Can it be separated (No) by physical means? Mixtures Pure substance (Yes) Is the composition (No) (yes) Can it be (No) uniform? decomposed by ordinary chemical
means?
Homogeneous Heterogeneous Compounds Elements