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Chapter 6 Chemical Reactions. Section 1 Observing Chemical Change. I. Properties and Changes in Matter. 1. Matter – Anything that has mass and takes up space. 2. Chemistry – the study of matter and how matter changes.
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Chapter 6 Chemical Reactions Section 1 Observing Chemical Change
I. Properties and Changes in Matter 1. Matter – Anything that has mass and takes up space. 2. Chemistry – the study of matter and how matter changes. 3. Physical Properties – characteristics that can be observed without changing the substance into another substance.
Examples: Color, temperatures for phase changes, texture, whether it dissolves in water, and how well it conducts heat and electricity. 4. Chemical Property – characteristics of a property that describe its ability to change into other substances.
Examples: Flammability, rusting, tarnishing. 5. Precipitate – A solid that forms from a solution during a chemical reaction. 6. Endothermic reaction – a reaction in which energy is absorbed. Example: baking soda and vinegar, making pancakes.
7. Exothermic reactions- a reaction in which energy is released. Examples: Combustion, hand warmers.
Chapter 6 ~ Section 2 Describing Chemical Reactions
Chemical Equation: a way to describe a chemical reaction using symbols instead of words. • Reactant: the substances you have at the beginning of a chemical equation. • Product: the new substances you have at the end of the equation.
H2 + O2 H2O Reactants Products
4. Conservation of Mass: in a chemical reaction, the total mass of the reactants must equal the total mass of the products. 5. Open System: A system where matter can enter or leave. Example: Fireplace
6. Closed System: A system where no matter can enter or leave. Example: Sealed plastic bag, closed beaker/flask.
7. Coefficient: A number placed in front of a formula in an equation. 2H2 + O2 2H2O Coefficients
8. Synthesis: when two or more elements or compounds combine to make a new substance. Example: Hydrogen and Oxygen making water. 9. Decomposition: when a compound breaks down into simpler substances. Example: Hydrogen Peroxide breaking down into water and oxygen gas. 10. Replacement: When an element replaces another element in a compound or when elements in different compounds trade places.
Balancing Equations Cu + O2 CuO
Balancing Equations Cu + O2 CuO
Balancing Equations 2Cu + O2 2CuO
A tougher example. CH4 + O2 CO2 + H20
A tougher example. CH4 + O2 CO2 + H20
A tougher example. CH4 + O2 CO2 + H20
A tougher example. CH4 + 2O2CO2 + 2H20