Download Lesson 4.01: Chemical vs. Physical Changes and Properties Define

Lesson 4.01: Chemical vs. Physical Changes and Properties
Define and identify chemical and physical properties and changes.
A physical property is an aspect of matter that can be observed or measured without
changing it. Examples of physical properties include color, molecular weight and volume.
A chemical property may only be observed by changing the chemical identity of a
substance. This property measures the potential for undergoing a chemical change.
Examples of chemical properties include reactivity, flammability and oxidation states.
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Give examples of physical and chemical properties and changes.
Physical properties: Properties that do not change the chemical nature of matter
Chemical properties: Properties that do change tha chemical nature of matter
With the definitions of each term in mind, here are some examples.
Chemical Properties
* iron rusting (iron oxide forms)
* gasoline burning (water vapor and carbon dioxide form)
* eggs cooking (fluid protein molecules uncoil and crosslink to form a network)
* bread rising (yeast converts carbohydrates into carbon dioxide gas)
* milk souring (sour-tasting lactic acid is produced)
* suntanning (vitamin D and melanin is produced)
Physical Properties
* whipping egg whites (air is forced into the fluid, but no new substance is produced)
* magnetizing a compass needle (there is realignment of groups ("domains") of iron atoms, but no real change within the
iron atoms themselves).
* boiling water (water molecules are forced away from each other when the liquid changes to vapor, but the molecules are
still H2O.)
* dissolving sugar in water (sugar molecules are dispersed within the water, but the individual sugar molecules are
unchanged.)
* dicing potatoes (cutting usually separates molecules without changing them.)
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Compare and contrast chemical and physical properties and changes.
Physical changes alter physical properties of a substance. These include breaking, melting, and dissolving.
Usually, physical changes are easily reversible. The physical appearance may change, but the chemical
composition remains the same. Chemical changes, on the other hand, change the substance into something
completely different. For example, when an item rusts, the metal reacts with oxygen, forming a compound
that resembles neither the metal nor oxygen: rust
Lesson 4.02: Balancing Equations
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Explain why it is important to always balance equations.
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Describe what coefficients represent and how they relate to the law of conservation of mass.
Use coefficients to balance a variety of chemical equations.
Lesson 4.03: Chemical Reactions: Double and Single Replacement
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Identify double and single replacement reactions when given the complete equation or the
reactants.
Predict the products of a double or single replacement reaction when given the reactants.
Use an activity series to determine if a single replacement reaction is possible.
Identify the common properties of single and double replacement reactions.
Lesson 4.04: Chemical Reactions: Synthesis and Decomposition
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Identify synthesis and decomposition reactions when given the complete equation or the
reactants.
Predict the products of a synthesis or decomposition reaction when given the reactants.
Identify the properties of synthesis and decomposition reactions.
Lesson 4.05: Chemical Reactions: Combustion
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Identify combustion reactions when given the complete equation or the reactants.
Predict the products of a combustion reaction when given the reactants.
Identify the properties of combustion reactions.
Be able to describe the reactions and observations from the laboratory activity.
Lesson 4.06: Stoichiometry
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Explain what the coefficients in a balanced equation represent and how they can be used in
ratios.
Use coefficients from a balanced equation as a mole ratio in dimensional analysis calculations.
Solve a variety of stoichiometry calculations involving moles and mass.
Use volume and density in stoichiometry calculations (honors).
Lesson 4.07: Limiting Reactant
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Identify when a problem is a limiting reactant problem based on the given information.
Calculate the theoretical yield of a reaction when given measured amounts of more than one
reactant.
Identify the limiting reactant and excess reactant in a problem.
Determine the amount of excess reactant left over after a reaction is complete (honors).
Lesson 4.08: Percent Yield
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Identify the actual yield and theoretical yield of a stoichiometry (including limiting reactant)
problem.
Determine the percent yield of a reaction.
Use percent yield to calculate the actual yield of a reaction.
Describe the procedure and results of the laboratory activity completed in this lesson.