PSc.2.1 OBJECTIVE: Understand types, properties and structure of matter.
Feb 11, 2016
PSc.2.1 OBJECTIVE: Understand types, properties and structure of
matter.
Objectives
PSc.2.1.1–Classify matter as: homogeneous
or heterogeneous; pure substance or mixture; element or compound; metals, nonmetals or metalloids; solution, colloid or suspension.
SHOE CLASSIFICATION ACTIVITY
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Matter Flowchart
MATTERCan it be
physically separated?
Homogeneous Mixture
(solution)Heterogeneous
MixtureCompound Element
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically
decomposed?
noyesIs the composition
uniform?
noyes
Colloids Suspensions
Homogeneous vs Heterogeneous
If matter is not uniform throughout, then it is a heterogeneous.
If matter is uniform throughout, it is homogeneous.
Homogeneous Matter
Salt water, apple juice and dust free air (mixture of nitrogen, oxygen, argon, carbon dioxide, water vapor and other gases) are examples of homogeneous materials.
Homogeneous Matter
Brass (solid mixture of copper and zinc) is also homogeneous.
Brass is an alloy, which is a mixture of metals.
Heterogeneous Matter
Oil-and-vinegar salad dressing, which has a layer of oil floating on a layer of vinegar, is heterogeneous.
Homogeneous vs. Heterogenous Matter
Classify the following substances and mixtures as either homogeneous or heterogeneous.
Flat soda pop, cherry vanilla ice cream, salad dressing, sugar, soil, aluminum foil, black coffee, sugar water, city air, paint, alcohol, iron, beach sand, pure air, spaghetti sauce.
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Homogeneous vs. Heterogeneous Matter
Homogeneous Sugar Aluminum foil Black coffee Sugar water Iron Pure air Alcohol Flat soda pop
Heterogenous Cherry vanilla ice cream Salad dressing Soil City air Paint Beach sand Spaghetti sauce
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Pure Substances
A pure substance always has the same composition.
Pure substances are either elements or compounds.
Elements are substances that cannot be broken down into other substances chemically or physically.
Examples include sodium, carbon and gold.
Elements
Elements
Elements– composed of identical atoms– Ex: copper wire, aluminum foil
Compounds
Compound– composed of 2 or
more elements in a fixed ratio
– properties differ from those of individual elements
– Ex: table salt
Another example of a compound includes water (hydrogen and oxygen).
Compounds
Mixtures
A mixture can be defined as something that has variable composition.
Soda is a mixture (carbon dioxide is dissolved in it), and coffee is a mixture (it can be strong, weak or bitter).
Heterogeneous Mixtures
A heterogeneous mixture contains regions that have different properties from those of other regions.
When we pour sand into water, the resulting mixture contains two distinct regions.
Homogeneous Mixtures
Homogeneous mixtures (also known as solutions) are mixtures in which the composition is uniform, there are no chunks or layers.
Substances vs. Mixtures
Classify the following as to whether it is a substance or a mixture.
Sodium, water, soil, coffee, oxygen, alcohol, carbon dioxide, cake batter, air, soup, iron, salt water, ice cream, nitrogen, eggs, blood, table salt, nail polish, milk, cola
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Substances vs. Mixtures
Substances Sodium (Na) Water (H2O) Oxygen (O2) Carbon Dioxide (CO2) Iron (Fe) Nitrogen (N2) Table Salt (NaCl)
Mixtures Soil Coffee Cake batter Air Soup Salt water Ice cream Eggs Blood Nail polish Milk Cola Alcohol
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Identification Activity
Classify the contents of each bag as an element, compound, or mixture.
Justify your answers.
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Pure Substances and Mixtures
A. gasoline
B. copper metal
homogeneous mixture
pure substance
Classify each of the following as a pure substance, a homogeneous mixture or a heterogeneous mixture.
Question
C. a stream with gravel at the bottom
D. chunky peanut butterheterogeneous mixture
heterogeneous mixture
Classify each of the following as a pure substance, a homogeneous mixture or a heterogeneous mixture.
Question
E. a multivitamin tablet
F. carbon dioxide gashomogeneous mixture
pure substance
Classify each of the following as a pure substance, a homogeneous mixture or a heterogeneous mixture.
Question
Quiz
1. _____ has mass and occupies space. 2. Elements _____ be broken down into
simpler substances. 3. Pure substances include _____ and _____. 4. The formula H2O formula represents a
_____ of water. 5. Mixtures are formed from _____ substances.
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Tyndall Effect
The Tyndall Effect is light scattering by particles in a colloid or particles in a fine suspension.
Tyndall Effect
The Tyndall Effect is shown on the left.
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Solution Colloid Suspension
type
particle size
Tyndall Effect
“Settle out”
Example
Mixtures
Solution– homogeneous– very small particles– no Tyndall effect– particles don’t settle– Ex: rubbing alcohol
Colloid– heterogeneous– medium-sized
particles– Tyndall effect– particles don’t
settle– Ex: milk
Mixtures
Suspension– heterogeneous– large particles– Tyndall effect– particles settle– Ex: fresh-
squeezed lemonade
Mixtures
A) mayonnaisecolloid
Question
Classify each of the following as a solution, colloid or suspension.
suspensionB) muddy water
C) fogcolloid
Question
Classify each of the following as a solution, colloid or suspension.
solutionD) salt water
E) Italian salad dressingsuspension
Question
Classify each of the following as a solution, colloid or suspension.
Quiz
1. A difference in what physical property is often used to separate two immiscible liquids?
2. Fog and smoke are examples of what type of heterogeneous mixture?
3. What is another term for a homogeneous mixture?
4. What is an alloy? 36
Quiz
1. The temperature at which a solid becomes a liquid.
2. Ability of a substance to burn in the presence of oxygen.
3. Ability of a substance to combine chemically with another substance.
4. Mass per unit volume of a substance.
a. Melting pointb. Boiling pointc. Density d. Reactivity e. Flammability
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