Science Crossword

3. the number placed in front of a chemical symbol or formula that shows how many atoms or molecules of the substance are involved in the reaction.
5. the symbolic representation of a chemical reaction in the form of symbols and chemicals.
6. a reaction to a question, experience, or some other type of stimulus.
8. changes, experiences, or feelings that occur within someone.
11. changes outside the body, or knowledge that is passed to us through our senses.
12. the number of atoms of an element according to the number on the bottom left.

1. the mass of the system must remain constant over time, as the system's mass cannot change, so the quantity can neither be added nor be removed.
2. a simple substance that cannot be broken down into smaller parts or changed into another substance.
4. a thing that is composed of two or more separate elements; a mixture.
7. the same number of atoms of each element are present on both sides of the equation.
9. If the number of atoms of each element in reactants is not equal to the number of atoms of each element present in product.
10. a thing or event that evokes a specific functional reaction in an organ or tissue.