1. Chemical Reactions
SPS2. Students will explore the nature of matter, its classifications, and its systems for naming types of matter.
d. Demonstrate the Law of Conservation of Matter in a chemical reaction.
Purpose: Determine why chemical equations have to be balanced.

2. Chemical Reaction
A process that involves a rearrangement of atoms, molecules, or ions.
Substances react together to form new substances with different properties.
Examples: Rust, formation of table salt and water

3. Chemical Equations Reactants → Products
Reactants are the substances that undergo change. Products are the new substances produced from the change.
Using Equations to Represent Reactions
Hydrogen + Oxygen → Water
A chemical equation is a representation of a chemical reaction in which the reactants and products are expressed as a formula.

4. Law of Conservation of Matter
The mass of the products is always equal to the mass of the reactants.
Mass is neither created nor destroyed in a chemical reaction.

5. Balancing Equations
Water is formed by the reaction of hydrogen with oxygen.
H2 + O2 → H2O, if you look at this closely, you will notice the number of O’s on each side is not the same.
In order to show that mass is conserved during a reaction, a chemical equation must be balanced.

6. Balancing Equations
Equations can be balanced by changing the coefficients, the numbers that appear before the formulas.
The first step to balancing an equation is to count the number of atoms of each element on each side of the equation.
2H2 + O2 → 2H2O, the equation is now balanced.

7. Chemical Calculations
Think about baking. A cake recipe tells you how much of each ingredient is needed to bake one cake. What if you want to make three cakes?
Chemical equations can be read as recipes for making new substances.

8. Chemical Calculations
2H2 + O2 → 2H2O
Two molecules of hydrogen react with one molecule of oxygen and form two molecules of water.
Two moles of hydrogen react with one mole of oxygen and form two moles of water.
4.0 grams of H2 reacts with 32.0 grams of O2 and forms 36.0 grams of H2O

9. Chemical Calculations
In chemical reactions, the mass of a reactant or product can be calculated by using a balanced chemical equation and molar mass of the reactants and products Reactants → Products unbalanced H2 + O2 → H2O balanced H2 + O2 → 2H2O

10. Balancing Chemical Equations Using the Tile Method3 2
__ N2 + __ H2  __ NH3 N2 H2
NH3 H2
NH3 H2

11. Balancing Chemical Equations Using the Tile Method2 2 4
__ Na2O2 + __ H2O  __ NaOH + __ O2
Na2O2
H2O
NaOH O2
Na2O2
H2O
NaOH
NaOH
NaOH

12. Activator Know Want to Know Learned
Create a KWL chart for Chemical Reactions
Know
Want to Know
Learned

13. What is a chemical reaction?
A process in which atoms of the same or different elements rearrange themselves to form a new substance. While they do so, they either absorb or give off heat.
Reactants → Products
Reactants are the substances that undergo change. Products are the new substances produced from the change.

14. What is a chemical equation?
A representation of a chemical reaction in which the reactants and products are expressed as formulas.
Using Equations to Represent Reactions
Hydrogen + Oxygen → Water

15. Law of Conservation of Matter
The mass of the products is always equal to the mass of the reactant.
Mass is neither created nor destroyed in a chemical reaction

16. Activator Balance the following equation
___ H2 + ___ O2  ___ H2O 2 2 H2 O2
H2O H2
H2O

17. Balancing Chemical Equations Atom Inventory Method
SPS2d. Demonstrate the Law of Conservation of Matter in a chemical reaction.

18. 1. Write the chemical equation.
C3H8 + O2  H2O + CO2

19. 2. List types of atoms present in the equation.
C3H8 + O2  H2O + CO2 Reactants Products C H O

20. C3H8 + O2  H2O + CO2 Reactants Products C 3 1 H 8 2 O 2 3
3. Count the number of atoms for each element; reactants then products.
C3H8 + O2  H2O + CO2 Reactants Products C 3 1 H 8 2 O 2 3

21. 4. Start with the first atom (C) and add coefficients to balance
C3H8 + O2  H2O + 3CO2
Reactants Products C H O

22. 5. Now balance the second atom (H) by adding a coefficient.
C3H8 + O2  4H2O + 3CO2
Reactants Products C H O

23. 6. Now balance the last atom type (O).
C3H8 + 5O2  4H2O + 3CO2
Reactants Products C H O

24. Balance the following ___ S8 + ___ O2  ___ SO3
___ HgO  ___ Hg + ___ O2
___ Fe + ___ O2  ___ Fe2O3
___ K + ___ Br2  ___ KBr
___ H2O2  ___ H2O + ___ O2

25. Balance the following ___ KClO3  ___ KClO4 + ___ KCl
___ P4O10 + ___ H2O  ___ H3PO4
___ Sb + ___ O2  ___ Sb4O6
___ N2 + ___ H2  ___ NH3
___ N2 + ___ O2  ___ N2O

26. Balance the following ___ Zn + ___ HCl  ___ ZnCl2 + ___ H2
___ Na + ___ H2O  ___ NaOH + ___ H2
___ C10H16 + ___ Cl2  ___ C + ___ HCl
___ Fe2O3 + ___ H2  ___ Fe + ___ H2O
___ C7H16 + ___ O2  ___ CO2 + ___ H2O

27. Balance the following ___ SiO2 + ___ HF  ___ SiF4 + ___ H2O
___ KClO3  ___ KCl + ___ O2
___ C3H8 + ___ O2  ___ CO2 + ___ H2O
___ Fe2O3 + ___ CO  ___ Fe + ___ CO2
___ PCl5 + ___ H2O  ___ HCl + ___ H3PO4

28. Balance the following ___ H2S + ___ Cl2  ___ S8 + ___ HCl
___ Fe + ___ H2O  ___ Fe3O4 + ___ H2
___ CO2 + ___ H2O  ___ C6H12O6 + ___ O2
___ SiCl4 + ___ H2O  ___ H4SiO4 + ___ HCl
___ H3PO4  ___ H4P2O7 + ___ H2O

29. What is wrong with . . .
H2 + O2  NaOH
2H2 + O2  2H2O

30. ____ Na + ____ Cl2  ____ NaCl
#1 Balance
____ Na + ____ Cl2  ____ NaCl

31. #2 Balance
____ H2O  ____ H2 + ____ O2

32. ____ CaCO3  ____ CaO + ____ CO2
#3 Balance
____ CaCO3  ____ CaO + ____ CO2

33. #4 Balance
___ Cu + ___ AgNO3  ___ Ag + ___ Cu(NO3)2

34. ___ K + ___ H2O  ___ H2 + ___ KOH
#5 Balance
___ K + ___ H2O  ___ H2 + ___ KOH

35. ___ Pb(NO3)2 + ___ KI  ___ PbI2 + ___ KNO3
#6 Balance
___ Pb(NO3)2 + ___ KI  ___ PbI2 + ___ KNO3

36. #7 Balance
___ CaCO3 + ___HCl  ___CaCl2 + ___ H2CO3

37. ___ HCl + ___ NaOH → ___ H2O + ___ NaCl
#8 Balance
___ HCl + ___ NaOH → ___ H2O + ___ NaCl

38. #9 Balance
___ Mg + ___ O2 → ___ MgO 

39. ___ MgCO3 → ___ MgO + ___ CO2
#10 Balance
___ MgCO3 → ___ MgO + ___ CO2

40. #11 Balance
___ KNO3 → ___ KNO2 + ___ O2

41. #12 Balance
___AgNO3 + ___NaCl → ___NaNO3 + ___AgCl

42. #13 Balance
___ Ag + ___ S → ___ Ag2S

43. ___ Cl2 + ___ KBr → ___ KCl + ___ Br2
#14 Balance
___ Cl2 + ___ KBr → ___ KCl + ___ Br2

44. #15 Balance
___ H2 + ___ O2  ___ H2O

45. #16 Name the Compound
N2O3

46. #17 Name the Compound
Al2O3

47. #18 Write the Formula
Iron (IV) Oxide

48. #19 Write the Formula
Potassium Phosphide

49. #20 Write the Formula
Diboron Pentaoxide