Transcript Unit 1 Intro to Chem & Matter and Change 2011 - Reeths

Chapter One
Introduction to
Chemistry
What is Chemistry?
 Define Chemistry -
• The study of the
composition of matter and
the changes it undergoes.
 Define Matter -
• Anything that has mass
and occupies space.
What are the five branches of
Chemistry?
 Organic Chemistry
 Inorganic
Chemistry
 Analytical
Chemistry
 Physical Chemistry
 Biochemistry
3.a. WHAT IS ORGANIC
CHEMISTRY?
STUDIES CARBON CONTAINING
COMPOUNDS.
• Hydrocarbons specifically
3.b. WHAT IS INORGANIC
CHEMISTRY?
STUDIES SUBSTANCES WITHOUT
CARBON.
• Mainly substances of nonliving
things.
3. c. WHAT IS ANALYTICAL
CHEMISTRY?
CONCERNED PRIMARILY WITH
IDENTIFYING UNKNOWN
SUBSTANCES.
• Lab based chemistry
• Forensic chemistry is an example
3. d. WHAT IS PHYSICAL
CHEMISTRY?
SPECIALIZES IN THEORIES AND
EXPERIMENTS THAT DESCRIBE THE
BEHAVIOR OF CHEMICALS.
• LOTS OF MATH
• DESCRIPTIVE CHEMISTRY: How and
why do materials behave the way
they do...
3.e. WHAT IS BIOCHEMISTRY?
STUDIES THE COMPOSITION OF
LIVING ORGANISMS.
• MEDICINES,
PHOTOSYNTHESIS/RESPIRATION,
CELL BIOLOGY, ETC.
IS THERE CLEAR DISTINCTION BETWEEN FIELDS?
NO!
 OBVIOUSLY THE SUBDIVISIONS OF CHEMISTRY
OVERLAP.
• FOR EXAMPLE, YOU CAN’T MEASURE A CHANGE IN
SUBSTANCE WITHOUT SOME PROFICIENCY IN
ANALYTICAL CHEMISTRY.
4. Why study chemistry?

Your everyday life
involves chemistry,
how?
a. Food Industry
b. Environmental
Reasons
c. Medical Advances
d. Better products
means better lives
HOW DOES CHEMISTRY AFFECT YOUR
EVERYDAY LIFE?
 VIDEO - “CHEMISTRY IN YOUR LIFE”
 Directions are in the notepack.
Chapter 2 (pg. 5 in Notepack)
Matter and Change
2.1 Properties of matter
1. Matter –
• Anything that has a mass and takes up space.
2. Mass –
• The amount of matter the object contains.
3. Substance –
• Matter that has uniform and constant
composition. It is pure. Contains only one kind
of matter.
2.1 Properties of Matter
Continued
4. Physical Property –
• A quality or condition of a substance that can
be observed or measured without changing
the substance’s composition.
Write these examples in the left-hand margin
Examples: Color, solubility, odor, hardness,
density, melting point, boiling point.
States of Matter
5. Solid –
• Matter with a definite (“fixed”) shape and volume.
6. Liquid –
• Matter that flows, has a fixed volume, and takes the
shape of its container.
7. Gas –
• Matter that takes both the shape and volume of its
container. Gases are easily compressed.
8. Vapor –
• A gaseous form of matter that is usually a solid or
liquid at room temperature
Physical Change
9. A change that alters matter without
changing its composition.
• Cutting, grinding, bending, boiling, freezing,
melting, etc.
Things to think about…
 Is every sample of matter a substance?
• Explain
Substance
 If a substance only defines pure matter –
that is matter that is only made up of one
kind of matter NOT EVERY TYPE OF MATTER IS A SUBSTANCE.
 In nature, we have mixtures – those forms
of matter that are made up of two or more
types of matter physically blended
together.
To review:
 List 5-7 physical properties of matter
Answer:
Color,
 solubility,
 odor,
 hardness,
 density,
 melting point,
 boiling point

Which of the following are physical
changes?
a)
b)
c)
d)
Making caramel from sugar
Carving a wooden figurine
Freezing mercury
Dissolving salt in water
Answers:
a)
b)
c)
d)
Making caramel from sugar: Chemical
Carving a wooden figurine: Physical
Freezing mercury: Physical
Dissolving salt in water: Physical
2.2 Classifying Mixtures
pg. 6 in your Note pack
1. Mixture:
• Variable composition - 2 or
more things put together,
each retaining it’s own
identity.
2. Heterogeneous Mixture
> 2 or more things put together, each retains
it’s own identity, but looks different
throughout.
> Has distinct phases
3. Homogeneous Mixture
> 2 or more things put together, each retains it’s
own identity, but looks uniform
throughout.
4.
solution
• A solution is a homogeneous
mixture
5. Phase
Any part of a system with uniform (“same”)
composition and properties.
• Salt water = One Phase
• Sand and Iron Filings = Two Phases
6. Distillation
 A process used to separate two liquids
from one another based on their boiling
point.
How do we separate mixtures?
What might be a way that we could separate a
mixture of sand and salt using only physical
changes?
Answer:
 Add water to dissolve the salt.
 Filter the saltwater through a funnel.
 Boil the water out of the salt water.
 Left with two separate piles of sand and
salt.
Your turn to Practice: Are the
following a Substance or a Mixture?
 Silver
 Alphabet soup
 Textbook
 Table salt (sodium chloride)
Answers:
Substance
 Alphabet soup - Mixture
 Textbook - Mixture
 Silver -
 Table salt (sodium chloride) -
Substance
Separate this mixture:
 What physical properties could be used to
separate iron filings from salt?
Answer:
 Iron is magnetic.
Use a magnet to pull out
the iron filings from the mixture.
Classify the following mixtures as either
Homogeneous or Heterogeneous?
 Spaghetti sauce with meatballs
 Glass
 Muddy water
 Cough syrup
 Mixture of nitrogen gas and helium gas
Answers:
 Spaghetti sauce with meatballs:
 Glass:
Hetero
Homo
Hetero
 Cough syrup: Homo
 Muddy water:

Mixture of nitrogen gas and helium gas: Homo
(gases will diffuse to blend completely)
Texting 101 – this is NOT in your
notes
 The following are shortened
representations of longer phrases. What
does each mean?
 Lol
 Ttyl
 Bff
 These are shorthand representations of a
longer meaning.
2.3 Element and Compounds
Note pack, pg. 7

Elements:
• The simplest form of matter
• Cannot be broken down further
• Found on the periodic table
• Represented by a chemical
symbol
–Sometimes from its English name,
sometimes from its Latin name
Compound
 2 or more elements CHEMICALY bonded
together.
 Still just one substance, but made of 2
or more kinds of atoms.
 Represented by a chemical
FORMULA
Symbol vs Formula

Chemical symbol:
• One or two letter abbreviation for the elements
• Found on the periodic table

Chemical formula:
• Shorthand for a compound
• Comprised of two or more chemical symbols
• May contain subscripts to denote how many
atoms of each element present in the compound.
Chemical Change
 To turn a compound into its elements, a
CHEMICAL CHANGE must occur.
 The elements comprising a compound have
very different properties.
 Water  Hydrogen gas + Oxygen gas
Practice the Chemical Symbols
 Copper
 Oxygen
 Phosphorus
 Silver
 Sodium
 Helium
Practice Naming
Sn
 Ca
S
 Cd
P
 Cl
K
 Mg
 Mn

Practice Classifying
element, compound or mixture
 Spaghetti sauce
 Glass
 Table sugar
 River water
 Cough syrup
 nitrogen
2.4 Chemical Reactions
CHEMICAL REACTION –
• shorthand for representing a
chemical change.
 Reactants – Starting substances
 Products – Ending substances
CH4 + O2  CO2 + H2O
Reactants  Products
Chemical Reactions
 Heating Iron and Sulfur strongly produces a
chemical change … iron sulfide is
produced.
 see the reaction here
Chemical Property
 The ability of a substance to undergo a
chemical reaction and to form new
substances.
• Iron metal has the ability to rust.
• Magnesium has the ability to react with acid.
Law of Conservation of Mass and
Energy
 During a chemical change, the total amount
of mass and energy is a constant.
 The mass and energy of the reactants
must equal the mass and energy of the
products.
Chemical Change vs Physical
Change
Chemical changes produces new substances.
 Physical changes do not produce new substances.

 Chemical changes can be observed by
things such as color changes,
•
•
•
•
heat changes (absorb heat = feel cold; release heat = feel warm),
formation of a gas (bubbles) ,
formation of a new solid (a precipitate solid suspended in a liquid) ,
mass changes, etc.
Practice
 Classify each as a chemical or physical
change
•
•
•
•
•
•
Cookies are baked
Water boils
Salt dissolves in water
A firefly emits light
Milk spoils
Metal chair rusts
Practice
 State several physical and chemical
properties that could be used to
distinguish between each of the following
pairs of substances and mixtures
•
•
•
•
Gasoline and water
Copper and silver
Water and salt water
Aluminum and steel
The Law of Conservation of Mass
 In any physical change or chemical
change, mass is neither created nor
destroyed; it is conserved.
• Mass of the products must equal the mass of
the original reactants
Practice
 Law of conservation of mass.
• Hydrogen and oxygen react chemically to form
water. How much water would be formed if 4.8
grams of hydrogen reacted with38.4 grams of
oxygen?
Practice
 Law of conservation of mass.
• Hydrogen and oxygen react chemically to form
water. How much water would be formed if 4.8
grams of hydrogen reacted with38.4 grams of
oxygen?
Hydrogen + Oxygen  Water
38.4 g
+
4.8 g  43.2 g
Summary
 On the back of our notes in the space
provided, let’s draw in the classification of
matter pyramid together. (page 38)