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chemistry part2
Term | Definition |
---|---|
Activation Energy | What is needed to start a chemical reaction. |
arrow | you read the arrow as "yields" in a chemical equation. |
characteristics of a chemical reaction | changes in energy or changes in properties (produce a gas (bubbles form), color change, precipitate forms or temperature) |
chemical changes | alter the chemical properties of matter; new substances with new properties are formed. |
chemical equations | a shorter, easier way to show chemical reactions by using symbols instead of words. |
coefficient | a number placed in from of a chemical formula in an equation. Tells how many atoms or molecules of each reactant and product take part in the reaction. |
conservation of mass | the amount of matter involved in a chemical reaction does not change. The total mass of the reactants and product take part in the reaction. |
decomposition reaction | a compound breaks down into simpler substances. |
endothermic reaction | an observable change in energy that show a chemical reaction took place; a reaction that takes heat from the solution, absorbs energy,, makes if feel cooler. |
exothermic reaction | an observable change in energy that show a chemical reaction took place; a reaction that releases heat; gives off energy, makes if feel warmer; most chemical reactions are this type. |
physical changes | alter only the physical properties of matter; mo new substances are formed. Can be a change in size, shape or color; change in phase (by increasing or decreasing temperature: solid, liquid, gas |
precipitate | a solid that forms from solution during a chemical reaction; observable change that show a chemical reaction took place. |
products | the materials you have after a chemical reaction; written on the right side of the formula. |
reactants | the materials you have at the beginning of a chemical reaction; written on the left side of the formula. |
replacement reaction | one part of a compound is displaced by an element or compound from another substance (also called displacement reaction) |
states of matter | pp. 46-50): solid liquid, and gas |
subscripts | show the number of atoms of and element in a molecule or the ratio of elements in a compound. |
synthesis reaction | two substances combine to form a new compound (also called composition reaction) |