Transcript WHAT IS CHEMISTRY PPTx

What is Chemistry?
THE STUDY OF MATTER
AND THE CHANGES THAT
TAKE PLACE WITH THAT
MATTER
The Chemistry World
What is Matter?
MATTER: ANYTHING THAT HAS
MASS AND TAKES UP SPACE
Mass – the amount of matter in something
Volume – the amount of space something occupies
Which of the following is
matter?
A car?
A box?
You?
What is a property?
PROPERTY: A
CHARACTERISTIC OF A
SUBSTANCE THAT CAN
BE OBSERVED
Physical Property
 Physical property: a property that can be observed
without changing the identity of the substance.
 Examples:
•
Luster: Does a ring shine/glisten?
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malleability: the ability to be hammered into a thin sheet
•
ductility: the ability to be stretched into a wire
•
melting point
•
boiling point
•
density
•
solubility
•
specific heat
Special Physical Properties
MELTING POINT: THE TEMPERATURE AT
WHICH A SUBSTANCE CHANGES FROM A
SOLID TO A LIQUID AT A GIVEN PRESSURE
WATER = 0oC
BOILING POINT: THE TEMPERATURE AT
WHICH A SUBSTANCE CHANGES FROM A
LIQUID TO A GAS AT A GIVEN PRESSURE
WATER = 100 O C
Chemical Property
 Chemical Property: Characteristics of a material
that CANNOT be observed without causing a
chemical change
 Examples:

Reacting with Oxygen (oxidation):
 Iron
Rust
 Apple Turning Brown
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Reacting with Acids:
 The
formation of compounds (What’s a compounds?! We will
get there!!!)

Flammable/Nonflammable
What is a Pure Substance?
 A sample of matter that has definite chemical and
physical properties and cannot be changed into a
simpler substance. (it’s homogeneous)
 Examples:
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Tin
Sulfur
Diamond
Water
Pure Sugar
Table Salt
What is a mixture?
 Combination of two or more pure substances that are
NOT chemically combined
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Substances are held together by physical forces, not chemical
No chemical change takes place
Each item keeps its properties in the mixture
Can be separated physically
2 Types of Mixtures
 Homogeneous Mixtures
 Molecules are mixed up in an even distribution
 Solutions are mixtures that appear to be in a single substance
 Heterogeneous Mixtures
 Molecules are NOT mixed up in an even distribution
 Parts can be filtered out of the mixture
Examples of Homogeneous Mixtures
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Sugar water
Lemonade
Kool-Aid
Soda
Air
Examples of Heterogeneous Mixtures
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Snow globe
Sand in a bucket of water
Muddy water
Italian Salad Dressing
What is an Element?
 Pure substances that cannot be separated into simpler
substances
 Elements are composed of ONE kind of atom
 Elements are the simplest substances
 All the elements on earth can be found on the Periodic
Table
 Examples: Oxygen (O), Carbon (C), Hydrogen (H),
Nitrogen (N)
What is a Molecule?
 Composed of two or more elements that are joined
by a chemical bond.

Elements can be the same: Ex: H2, O2, N2

Elements can be different: Ex: C6H12O6, H2O
Only 1
element
MOLECULES
More than 1
element
What is a Compound?
 Pure substance composed of two or more DIFFERENT
elements joined by chemical bonds
 Compounds are a TYPE of MOLECULE!
 Can be only separated by chemical means, not physically
 Have their own physical and chemical properties
 Examples:
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H20 ---water
NaCl ----salt
NH3 ---ammonia
TiO—white out
ANALOGY
 Imagine going to an ice cream store.
 Let's say that they have 30 different flavors of ice
cream. Those are elements, the things that I have
available to build my dessert from.
 The smallest amount of ice cream that the store will
sell to me is a scoop. This is an atom.
 If I want, I can put two or more scoops of ice cream
together. This is a molecule.
 If my molecule has more than one flavor of ice
cream, I can call it a compound.
What is a Solution?
- Solute: Substance being dissolved
- Solvent: Substance the solute is dissolved in
STC LESSON 1:
The Nature of Matter
OBJECTIVES:
1. DISCUSS YOUR UNDERSTANDING OF THE TERMS PURE
SUBSTANCE AND MIXTURE.
2. OBSERVE MATTER IN THE FORM OF PURE SUBSTANCES
AND MIXTURES
3. USE YOUR OWN WORDS AND IDEAS TO EXPLAIN YOUR
OBSERVATIONS
NOTE:
**MAKE SURE YOU READ ALL INSTRUCTIONS AND
FOLLOW ALL PROCEDURES EXACTLY THROUGHOUT
THE LESSON**
WE WILL WALK THROUGH LESSON 1.1 TOGETHER THIS
TIME!!!
STC LESSON 2:
Pure Substance or Mixture?
OBJECTIVES:
1. DISCUSS YOUR UNDERSTANDING OF THE TERMS “PURE
SUBSTANCE”.
2. DISCUSS HOW YOU DISTINGUISH BETWEEN PURE
SUBSTANCES AND MIXTURES.
3. USE YOUR OWN TECHNIQUES TO DISCOVER WHETHER
SEVERAL SAMPLES OF MATTER ARE PURE SUBSTANCES
OR MIXTURES
NOTE:
**MAKE SURE YOU READ ALL INSTRUCTIONS AND
FOLLOW ALL PROCEDURES EXACTLY THROUGHOUT
THE LESSON**