Terms : Hide Images
| 5169245621 | signs of physical changes | water evaporation, ice melting, sugar dissolving in water, which are all changes that can be reversed | 0 | |
| 5169248810 | signs of a chemical reaction | color change, production of heat or light, formation of a new solid, liquid or gas | 1 | |
| 5169454676 | atoms | building blocks of matter | 2 | |
| 5169458552 | proton + neutron (neutral) electron - | the three particles of an atom and their charges | 3 | |
| 5169467696 | element | a pure substance made of one type of atom that can not be broken down by physical or chemical means | 4 | |
| 5169471742 | compound | a pure substance formed of two or more elements | 5 | |
| 5169478696 | electrons | what atoms share when they form a covalent bond | 6 | |
| 5169483319 | ionic bond | a bond that is formed when one atom is positively charged and another atom is negatively charged. | 7 | |
| 5169493261 | Van Der Waals forces | weak attractive forces between separate molecules | 8 | |
| 5169501796 | more neutrons | How one isotope of Carbon (C12) differs from another isotope of Carbon (C14) | 9 | |
| 5169514217 | Hydrogen flouride or Hydrogen oxide H2O | give an example of a compound tat forms a covalent bond. | 10 | |
| 5169386722 | exothermic reaction | A chemical reaction where energy is released is called an _____________________ ____________________ |  | 11 |
| 5169389312 | endothermic reaction | a reaction where energy is absorbed |  | 12 |
| 5169402771 | activation energy | what an enzyme lowers in a biological reaction | 13 | |
| 5169406447 | catalyst | it speeds up the process in a chemical reaction | 14 | |
| 5169410168 | enzyme | a biological catalyst- speeds up biological reactions | 15 | |
| 5169416135 | NaCl sodium chloride | a substance with at least one ionic bond |  | 16 |
| 5169429449 | chemical reaction | a process by which atoms or groups of atoms are reorganized into different substances | 17 | |
| 5169436753 | activation energy | the extra energy needed to get a reaction started | 18 | |
| 5169446493 | iron oxide | a product made from a nail rusting | 19 | |
| 5169448137 | oxygen | a reactant when paper burns | 20 |
