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2.1 Classifying Matter
Do Now• Identify the following:• C• H• O
• H2O
• CO2
• NaCl
• C6H12O6
• What do they all have in common?
2.1 Classifying Matter
Do Now• Identify the following:• C Carbon• H Hydrogen• O Oxygen
• H2O Water
• CO2 Carbon dioxide
• NaCl Sodium chloride
• C6H12O6 Glucose
• What do they all have in common? Made of atoms, matter; are elements or are elements joined to make a compound
2.1 Classifying Matter
Standards
• CLE 3202.1.1 Explore matter in terms of its physical and chemical properties.
• CLE 3202.1.5 Evaluate pure substances and mixtures.
• CLE 3202.1.4 Investigate chemical and physical changes.
2.1 Classifying Matter
Objectives• Classify pure substance
as elements or compounds.
• Describe the characteristics of an element and the symbols used to identify elements.
• Describe the characteristics of a compound.
• Distinguish pure substances from mixtures.
• Classify mixtures as heterogeneous or homogeneous.
• Classify mixtures as solutions, suspensions, or colloids.
2.1 Classifying Matter
A pure substance is matter that always has exactly the same composition.
• Table salt and table sugar are two examples of pure substances.
• Substances can be classified into two categories—elements and compounds.
Every sample of a given substance has the same properties because a substance has a fixed, uniform composition.
Pure Substances
2.1 Classifying Matter
An element is a substance that cannot be broken down into simpler substances.
Elements
An element has a fixed composition because it contains only one type of atom.
No two elements contain the same type of atom.
2.1 Classifying Matter
Symbols for Elements
Chemists use symbols of one or two letters to represent elements. The first letter is always capitalized. If there is a second letter, it is not capitalized.
Ex. C (carbon) Al (aluminum) Au (gold)
Elements
2.1 Classifying Matter
A compound always contains two or more elements joined in a fixed proportion.
Ex. H2O (water)
C6H12O6 (sucrose)
NaCl (salt)
Compounds
A compound is a substance that is made from two or more simpler substances and can be broken down into those simpler substances (Elements or other compounds.
Compounds must be separated by some chemical process!!
2.1 Classifying Matter
Frayer Model
2.1 Classifying Matter
TOTD• Reviewing Concepts
• p. 44 #1-3
2.1 Classifying Matter
Do Now• Identify the following mixtures as Homogeneous (HO) or
Heterogeneous (HE):• Italian Dressing• Apple juice• Sand• Kool-Aid• Orange juice with pulp• House Salad• Black coffee
2.1 Classifying Matter
The properties of a mixture can vary because the composition of a mixture is not fixed.• Mixtures can retain some of the properties of their
individual substances. • The properties of a mixture are less constant than the
properties of a substance.
Mixtures
2.1 Classifying Matter
Do Now• Identify the following mixtures as Homogeneous (HO) or
Heterogeneous (HE):• Italian Dressing - (HE)• Apple juice - (HO)• Sand - (HE)• Kool-Aid - (HO)• Orange juice with pulp (HE)• House Salad (HE)• Black coffee - (HO)• Think about the consistency of the 2 types mixtures. What
makes them different from each other?
2.1 Classifying Matter
Mixtures can be classified by how well the parts of the mixture are distributed throughout the mixture.
Heterogeneous Mixtures
In a heterogeneous mixture, the parts of the mixture are noticeably different from one another.
Homogeneous Mixtures
In a homogeneous mixture, the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another.
Mixtures
2.1 Classifying Matter
The sand is a heterogeneous mixture of different kinds of grains. The spoon is stainless steel, a homogeneous mixture of iron, chromium, and nickel.
Mixtures
2.1 Classifying Matter
Solutions
When substances dissolve and form a homogeneous mixture, the mixture that forms is called a solution.
Suspensions
A suspension is a heterogeneous mixture that separates into layers over time.
Solutions, Suspensions, and Colloids
2.1 Classifying Matter
Colloids
A colloid contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension.
• Like solutions, colloids do not separate into layers.
• You cannot use a filter to separate the parts of a colloid.
Solutions, Suspensions, and Colloids
2.1 Classifying Matter
These liquids represent three categories of mixtures.
• Windshield wiper fluid is a solution. • Muddy water collected from a swamp is a
suspension. • Milk is a colloid.
Solutions, Suspensions, and Colloids
2.1 Classifying Matter
Checks for Understanding
1. Which of these substances is a compound? a. copper
b. water
c. oxygen
d. carbon
2.1 Classifying Matter
Checks for Understanding
1. Which of these substances is a compound? a. copper
b. water
c. oxygen
d. carbon
ANS: B
2.1 Classifying Matter
Checks for Understanding
2. Which of these groups of letters could be used as a symbol for an element? a. HF
b. Cm
c. Car
d. fe
2.1 Classifying Matter
Checks for Understanding
2. Which of these groups of letters could be used as a symbol for an element? a. HF
b. Cm
c. Car
d. fe
ANS: B
2.1 Classifying Matter
Checks for Understanding
3. Which of the following statements does not apply to a compound? a. It is made of two or more elements.
b. It has components that are joined in fixed proportions.
c. It can be separated into components by physical methods.
d. It can be broken down into elements or other compounds.
2.1 Classifying Matter
Checks for Understanding
3. Which of the following statements does not apply to a compound? a. It is made of two or more elements.
b. It has components that are joined in fixed proportions.
c. It can be separated into components by physical methods.
d. It can be broken down into elements or other compounds.
ANS: C
2.1 Classifying Matter
Checks for Understanding
4. How does a compound differ from a mixture? a. A compound cannot be broken down into simpler
substances.
b. Compounds can be separated by physical processes and mixtures cannot.
c. The composition of a mixture cannot vary.
d. A compound is made of two or more elements in fixed proportion.
2.1 Classifying Matter
Checks for Understanding
4. How does a compound differ from a mixture? a. A compound cannot be broken down into simpler
substances.
b. Compounds can be separated by physical processes and mixtures cannot.
c. The composition of a mixture cannot vary.
d. A compound is made of two or more elements in fixed proportion.
ANS: D
2.1 Classifying Matter
Checks for Understanding
5. Which of these materials is a heterogeneous mixture? a. air
b. seawater
c. sand
d. steel
2.1 Classifying Matter
Checks for Understanding
5. Which of these materials is a heterogeneous mixture? a. air
b. seawater
c. sand
d. steel
ANS: C
2.1 Classifying Matter
Checks for Understanding
6. Which of the following can be separated with a filter? a. colloids
b. compounds
c. solutions
d. suspensions
2.1 Classifying Matter
Checks for Understanding
6. Which of the following can be separated with a filter? a. colloids
b. compounds
c. solutions
d. suspensions
ANS: D
2.1 Classifying Matter
Complete the classification of matter worksheets.
2.1 Classifying Matter
TOTD• Standardized Test Prep
• p. 65 #1, 5, 6
