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Chemistry Quiz 9/19
Question | Answer |
---|---|
Physical Change | A change that alters a substance’s appearance, without changing its chemical composition |
Examples of Physical Changes | Cutting and ripping paper, Molding clay, Crushing an aluminum can, phase changes |
Chemical Change | A change in which the identities of substances are changed and new substances are formed |
Examples of Chemical Changes | Iron rusting, Wood burning, Metal corroding, food spoiling, chemical reactions |
Chemical Change Key Words | Decomposing, rusting, exploding, oxidizing, corroding, tarnishing, reacting, burning, rotting, etc. |
Evidence of a chemical reaction | Formation of a gas, change in temperature, color change for a reaction |
Smallest unit of matter | Atom |
Physical Properties of Matter | Info that can identify and describe matter: color or texture, appearance, density, melting point, boiling point, odor |
Chemical Properties of Matter | Describes how matter acts during a reaction; reactivity (in acid, in the air), flammability, toxicity |
Two Categories of Matter | Pure Substances, Mixtures |
Pure Substances | Matter that has definite chemical and physical properties (elements and compounds) |
Element | A substance containing atoms of only one type |
Diatomic Element | A special element found in pairs in nature |
Compounds | Contain atoms of two or more different elements, chemically combined |
Mixtures | The addition of 2 or more elements and/or compounds that are not chemically combined |
Two types of mixtures | Heterogenous and Homogenous |
Heterogenous Mixtures | Not uniform throughout, ex; mixed peanuts, trail mix, chex mix, a salad |
Homogenous Mixtures | A substance with uniform composition throughout, the proportion of ingredients remains consistent |
Homogenous Solutions | Made by dissolving one or more substances (solutes) into another substance (solvent) |
Examples of Homogenous Solutions | Salt water (solid in liquid), rubbing alcohol (liquid in solid), the air (gases in gases), soda (gas in liquid), bronze (solid in solid) |