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Definitions CH 6
Exam 3
| Question | Answer |
|---|---|
| Physical change | the chemical composition of the substance is the same. Ex melting ice, boiling water |
| Chemical change | the chemical composition of the substance changes. There is a chemical reaction that makes a new substance |
| Chemical compounds of fireworks (ions or ionic compounds) | Na (orange-yellow), Ba (green-yellow), Ca (red-orange), Sr (bright red), Li (scarlet red), Cu (blue-green), Al & Mg (white sparks) |
| Four observations of a chemical reaction | Gas release (fizzing or bubbling) Insoluble solid (ppt)that forms from 2 aq sol Permanent color change (new substance) Heat energy change (Ex. heat and light ) |
| Aqueous solution | Substance dissolved in water |
| Precipitate (ppt) | insoluble solid formed after adding 2 aqueous solutions together |
| Exothermic reaction | Reaction that releases heat |
| Endothermic reaction | Reaction that absorbs heat |
| Chemical equation | description of a chemical reaction using formulas and symbols |
| Reactants | A + B - |
| Products | - C + D |
| Catalyst | Speeds up the reaction without being comsumed (above the arrow) |
| 7 Diatomic Molecules | H, Ni, O F, Cl, Br, I |
| Balance chemical equation | the number of atoms of each element is the same on both sides of the arrow |
| Coefficient | Whole # in front of each substance used to balance chemical reactions. |