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11 Cards in this Set
- Front
- Back
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physical changes are changes that affect what? |
The physical properties of a substance |
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What are the 3 physical properties? |
Size, shape and state |
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What are chemical changes? |
Involves the breaking of bonds in one or more substances and the reforming of new bonds to create new substances |
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How do you know chemical changes have occurred? |
When you get products that are different from the starting substances |
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4 signs of chemical changes: |
1. Temperature change (chemical bonds are changing) 2. Color change (A new substance is forming) 3. Bubbling (A new gas is forming) 4. Turns cloudy (A new solid is forming) |
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What is a chemical equation? |
A system using chemical formulas, words, and symbols to represent a reaction Ex: methane + oxygen -> carbon di. + water Reactants Products Subs. that change Subs. that are formed |
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Reactants are... |
Substances that enters into and is altered in a chemical reaction |
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Products are... |
The substances that are produced in a chemical reaction |
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Some elements are so reactive that they never exist as a single atom in nature. These are called: |
Diatomic molecules |
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When ever diatomic molecules are written in a chemical reaction, they must always... |
Be written as a pair |
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Important diatomic pairs: |
H2 N2 O2 F2 Cl2 Br2 |
