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42 Cards in this Set
- Front
- Back
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matter
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anything that takes up space and has mass
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chemistry
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the study of MATTER and and how matter CHANGES
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physical property
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a characteristic of a substance that can be:
OBSERVED *WITHOUT changing the substance into another substance |
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chemical property
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a characteristic of a substance that describes the its ability to
CHANGE into another substance |
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reactant
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the substance that that undergo change in a chemical reaction
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product
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the new substances formed by the reaction
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precipitate
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is a SOLID that formsfrom solutionduring a chemical reaction
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endothermic reactions
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the total making & breaking of bonds results in a
net ABSORBTION of energy ***energy is absorbed as heat from nearby matter |
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exothermic reactions
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the total making & breaking of bonds results in a
net RELEASE of energy |
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example of endothermic reaction
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baking soda & vinegar
the surrounding become cooler as energy os absorbed |
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example of an exothermic reaction
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fuel & oxygen in an airplane
releases heat into nearby matter |
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Chemical equation
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is a short easy way to show a chemical reaction using
SYMBOLS instead of words |
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conservation of matter
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during a chemical reaction matter isneither created or destroyed
** the total mass of reactants= total mass of products |
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open system
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matter can ENTER or ESCAPE
to surroundings burning match |
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closed system
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matter is not allowed to enter or leave
pear decaying under glass |
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coefficient
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a number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved
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synthesis
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a chemical reaction in which 2 or more simple substances combine to form a new more complez substance
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decomposition
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a chemical reaction
that breaks down compounds to simpler products |
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replacement
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a reaction
in which 1 element REPLACES another in a compound or when 2 elements in different compounds trade places |
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what information does a chemical equation contain?
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use chemical formulas and symbols insteas of words to
summerize a chemical reaction |
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How is matter conserved during a chemical reaction
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a chemical equation must show the same number of each type of atoms on both sides of the equation
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3 types of chemical reactions
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1. synthesis
2. decompositon 3. replacement |
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Conservation of Atoms
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in chemical reactions the # of atoms stays the same no matter howthey are arranged
* mass stays the same |
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Activation Energy
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the MINIMUM amount of energy needed to get a chemical reaction started
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concentration
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the amount of of one material in a certian volume of another material.
ex. 5g of salt in 100ml of water = 5% salt |
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catalyst
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a material that increases the rate of a reaction by lowering the activation energy
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enzyme
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a BIOLOGICAL catalyst that lowers the activation energy in
cells |
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inhibitor
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a material that decreases the RATE of the reaction.
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combustion
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a rapid reaction reaction between OXYGEN & FUEL
= FIRE!!! |
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How is activation energy related to chemical reactions?
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all chemical reactions require a certain amount of activation energy to get started
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What factors affect the rate of a chemical reaction?
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1. Surface area
2. Temperature 3. Concentration 4. presence of catalysts or inhibitors |
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How do you think an inhibitor affects the the rate of a chemical reaction?
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Decreases it
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In what type of reaction do the reactants have less energy than the products?
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Endothermic reaction
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Why may an increase in temperature affect the rate of a chemical reaction?
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may allow the particles to have more energy so they are more likely to come into contact with each other and to reac the activation energy.
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Fuel
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a materialthat releases energy when it burns
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What are the 3 things necessary to maintain a fire?
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1. Fuel
2. Oxygen 3. Heat |
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Why should you know about the causes of fire and how to prevent a fire?
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to know how to prevent fires in your home and what to do if it starts you are more prepared to take action and NOT DIE!
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Physical Change
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is any change that alters the form or apperance but does not change the substance into anther substance
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Chemical Change
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a change in matter that produces one or more substances
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How can changes in matter be descibed?
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changes in matter can be described in terms of
PHYSCIAL & CHEMICAL changes |
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How can you tell when a chemical reaction occurs?
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Chemical changes occur when bonds break and new bonds form
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4 examples of physical change
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melting, freezing, boiling, condensing
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