Science Vocab chapter 4

5. the new substances that form.
6. a solid that forms from liquids during a chemical reaction.
9. A change in matter that produces one or more new substances.
14. any change that alters the form or appearance of a substance but does not change it into another substance.
15. substances that undergo the chemical changes.
16. states that during a chemical reaction matter is not created or destroyed.
18. matter does not enter or leave

1. when one element replaces another element in a compound, or if two elements in different compounds trade places, the reaction is a replacement.
2. a number placed in front of a chemical formula in an equation.
3. more energy is required to break the bonds of the reactants than is released by the formation of the products.
4. a way to show a chemical reaction, using symbols instead of words.
7. the cells in your body contain thousands of biological catalysts called...
8. A material used to decrease the rate of a chemical reaction is an...
10. the energy released as the products form is greater than the energy required to break the bonds of the reactants.
11. the minimum amount of energy needed to start a chemical reaction.
12. the amount of a substance in a given volume.
13. occurs when compounds break down into simpler products.
17. matter can enter from or escape to the surroundings.
18. increases the reaction rate by lowering the activation energy needed.
19. in chemistry when two or more elements or compounds combine to make a more complex substance, the reaction is classified as...