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32 Cards in this Set
- Front
- Back
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How can matter be classified?
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Every sample of matter is either an element, compound, or mixture
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Why are carbon and copper classified as elements?
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Each element is made up of one kind of element.
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How are elements represented?
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by symbols, one or two letters
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How do atoms make up a molecule?
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atoms act as a unit, atoms can join to make molecules
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How are elements related to compounds?
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Each molecule of a compound contains 2 or more elements that are chemically combined
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Do compounds have unique properties?
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Yes, every compound differs from the elements it contains
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what do chemical formulas represent?
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compounds, the number of atoms and molecules in each element
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What is the difference between a pure substance and a mixture?
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Elements and compounds are pure substances, but mixtures are not.
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How are mixtures classified?
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by how well the substances mix...heterogeneous, homogeneous, miscible, and immiscible
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Can gases mix with liquids?
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yes, bubbles escape to the top formed from the gas
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Why are color, volume and density classified as physical properties?
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physical properties are characteristics that can be observed without changing the identity of the substance
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How can physical properties help identify substances?
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use observations and measurements to identify substances
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How are physical properties observed or measured?
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observe with 5 senses and find the measure
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What can physical properties help determine?
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uses, recognize and select substances by their physical properties
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Why is density a physical property?
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because it is a measurement of how much matter is contained in a certain volume of a substance
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equation for density
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density= mass/volume
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How is density different from weight?
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density is how much matter in a volume and weight is the gravity force
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Why are flammability and reactivity classifed as chemical properties?
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chemical property describes how a substance changes into a new substance, either by combining with other elements or by breaking apart into a new substance
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Why is flammability a chemical property?
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because it has the ability to burn
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Why is reactivity a chemical property?
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because it can combine
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Why are physical and chemical properties different?
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physical (observe without change) and chemical (observe with change)
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Do physical changes change a substances identity?
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no, examples are cutting, crushing, reshaping, changing shape
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Is dissolving a physical change?
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yes, molecules spread
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Why is getting a haircut an example of a physical change?
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physical change affects one or more physical properties of a substance without changing the identity of a substance
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Why is burning bread an example of a chemical change?
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chemical change when one or more substances are changed into entirely new substances that have different properties
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Do chemical changes happen everywhere?
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yes, more often than you think. ex. burning, rusting, digesting, decomposing
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what do chemical changes form?
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new substances, interaction cause chemical changes
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how can chemical changes be detected?
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clues like change in odor, color, fizzing, and production of sound, heat, or light
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Can chemical changes be reversed by physical changes?
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no, you can't go back or reverse with chemical changes but you can with physical changes
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How can mixtures and compounds be broken down?
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mixtures can be seperated by physical changes but compounds must be broken down by chemical changes
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can mixtures be physical seperated?
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yes, each substance keeps its identity so it can be seperated physically
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can some compounds be broken down through chemical changes?
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yes, broken into elements
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