1. What are the 5 signs of evidence that a chemical reaction has occurred?
2. What is a combination of symbols and numbers that represent the number and types of elements (atoms)
present in a compound?
3. What is a small number to the right of a symbol that is written below the normal line of letters to show how
many atoms of an element are present in a substance?
4. What is a solid that forms as a result of a chemical reaction? It will fall to the bottom of the container.
5. What are the formulas written on the left side of the arrow symbol (
reaction?
) are the starting substances in a chemical
6. What law states that matter is not created or destroyed, only changed? The number of atoms in the reactants
must be equal to the number of atoms in the product.
7. What is a change in which a substance (or substances) is changed into one or more new substances with different
properties than the original substances?
8. What is a combination of chemical formulas used to describe what happens in a chemical reaction? The equation
identifies the reactants and resulting product
9. What is a change in which the characteristics of a substance are only changed physically and the original
properties stay the same?
10. What are the formulas written on the right side of the arrow symbol  are the new substances formed in a
chemical reaction.
11. What is one or two letters used to represent an element?
12. What is an arrow symbol that shows a reaction has taken place?
13. What is a number written in front of a chemical formula to show how many molecules of that substance are
present?
14. What is it called when substances interact to form one or more new substances with different properties than
the original substances?
15. What is the subscript of oxygen in the chemical formula? 4CaC2O3
16. What is the coefficient of the Chlorine (Cl) molecule in the chemical equation?
17. What is the coefficient of the Sodium (Na) molecule in the chemical equation?
3Na + Cl2  3NaCl
3Na + Cl2  3NaCl
18. Make a t-chart to see if the equation is balanced. SO3 + H2O  H2SO4
19. Make a t-chart to see if the equation is balanced. N3 + 3H2  2NH3
20. Write an equation that shows water (H2O) forming when Hydrogen (H) reacts with Oxygen (O).
21. Make a t-chart to see if the equation is balanced. 2KCl + 3O2  2KClO