Conservation of Matter and Balancing Equations

1. Conservation of Matter
and
Balancing the Equation
Peking

2. Oxygen
O O

3. Hydrogen
H H

4. Oxygen
O O
What type of bond does
O2 have?

5. Oxygen
O O
What type of bond does
O2 have?
Two, it is double bonded

6. Hydrogen
H H
What type of bond does H2
have?

7. Hydrogen
H H
What type of bond does H2
have?
One, it is single bonded

8. Gas: Oxygen and Hydrogen
• How many oxygen atoms do you
see?

9. Gas: Oxygen and Hydrogen
• How many oxygen atoms do you see?
Two

10. Gas: Oxygen and Hydrogen
• How many oxygen atoms do you see?
Two

11. Gas: Oxygen and Hydrogen
• How many oxygen molecules do you
see?

12. Gas: Oxygen and Hydrogen
• How many oxygen molecules do you
see?
ONE

13. Gas: Oxygen and Hydrogen
• How many oxygen molecules do you
see?
ONE

14. Gas: Oxygen and Hydrogen
• How many hydrogen atoms do
you see?

15. Gas: Oxygen and Hydrogen
• How many hydrogen atoms do
you see?
Four

16. Gas: Oxygen and Hydrogen
• How many hydrogen atoms do
you see?
Four

17. Gas: Oxygen and Hydrogen
• How many hydrogen molecules
do you see?
Two

18. O2 +2H22H2O
O O
H H H H
Balancing the Equation

19. O2 +2H22H2O
O O
H H H H

20. O2 +2H22H2O
O O
H H H H

21. O2 +2H22H2O
O O
H H H H

22. O2 +2H22H2O
O O
H H H H

23. O2 +2H22H2O
O O
H H H H

24. O2 +2H22H2O
O O
H H H H
Conservation of Matter

25. O2 +2H22H2O
Conservation of Matter
reactant
Subscript

26. O2 +2H22H2O
Conservation of Matter
reactant
Subscript
Tells us how many of the element

27. O2 +2H22H2O
Conservation of Matter
reactant
What is this?
Tells us how many of the element

28. O2 +2H22H2O
Conservation of Matter
reactant
Subscript
What does it tell us?

29. O2 +2H22H2O
Conservation of Matter
reactant
Subscript
Tells us how many of the element

30. O2 +2H22H2O
Conservation of Matter
reactant
Refers to the Hydrogen

31. O2 +2H22H2O
Conservation of Matter
reactant
Refers to the MOLECULE

32. O2 +2H22H2O
Conservation of Matter
reactant
(2x2=4)
4 hydrogens

33. O2 +2H22H2O
Conservation of Matter
reactant
(2x2=4)
4 hydrogens
2 oxygens
This molecule

34. O2 +2H22H2O
Conservation of Matter
(2x2=4)
4 hydrogens
2 oxygens
This molecule

35. Questions- Answer now
1. The valence electron of Oxygen, and how many
does it need to be stable?
2. The valence electron of carbon, and how many
does it need to be stable?
3. With how many elements can oxygen react?
4. With how many elements can hydrogen react?
5. With how many elements can carbon react?

36. • With how many elements can oxygen react?
• 4.With how many elements can hydrogen
react?
• 5.With how many elements can carbon react?
• 6. CO2 – How many oxygen atoms?
• 7. CO2 – How many Carbon atoms?

37. Questions- Answer now
6. CO2 – How many oxygen atoms?
7. CO2 – How many Carbon atoms?
8. NaCl– How many chlorine atoms?
9. 4CO2 – How many oxygen atoms?
10. 4CO2 – How many Molecules?
11. What have you learned

38. Word Wise
• The root equ- means “even” or
“equal”.
– Balanced
– The same

39. Word Wise- It’s wise to know them
Vocabulary
- chemical formula
- chemical equation
- reactant
- product
- law of conservation of mass
•Page 262-64

40. chemical formula
• All substances are formed from ~ 100
elements
– All substances = Everything
• Shorthand way to represent a substance.

41. chemical formula
• All substances are formed from ~ 100
elements
– All substances = Everything
• Shorthand way to represent a substance.
• Todas las sustancias se forman a partir de ~ 100
elementos
• Todas las sustancias = Todo

42. chemical formula
• How many carbons in sugar? ¿Cuántos átomos de
carbono en el azúcar?
– Hydrogens?
– Oxygens?

43. COEFFICIENT
5C6H12O6
COEFFICIENT

44. COEFFICIENT
5C6H12O6
COEFFICIENT
coefficient is a number that is placed in
front of a chemical symbol or formula

45. chemical formula
• How many carbons in sugar?
–Hydrogens?
–Oxygens?
5C6H12O6
Come back to naming
page 263

46. chemical formula
• How many carbons in sugar?
– Hydrogens?
– Oxygens?
5C6H12O6
C = 30
H = 60
O= 30
Come back to naming
page 263

47. COEFFICIENT
If you see 4O2 in an equation, what is the
coefficient?
How many oxygen molecules?
How many oxygen atoms?

48. More parts of a chemical equation
The formulas of the reactants are written
before the arrow .

49. More parts of a chemical equation
• The formulas of the reactants are written
before the arrow .
+the two formulas are going to
combine

50. More parts of a chemical equation
• Product written after the arrow.

51. Reactants Product

52. Which is Product?
Which are Reactants?
• Plus sign =
– the reactants are added together.
• The arrow points to the products.

53. A Balanced Equation
NaHCO3 + CH3COOH → CO2
+ H2O + Na+ + CH3COO-

54. A Balanced Equation
NaHCO3 + CH3COOH → CO2
+ H2O + Na+ + CH3COO-

55. A Balanced Equation
NaHCO3 + CH3COOH → CO2 + H2O + Na+ +
CH3COO-
1.How many Na on reactant side?
2.How many H on reactant side?
3.How many C on reactant side?
4.How many O on reactant side?

56. A Balanced Equation
NaHCO3 + CH3COOH → CO2 + H2O + Na+ +
CH3COO-
5. How many Na on product side?
6. How many H on product side?
7. How many C on product side?
8. How many O on product side?

57. Explain if you think the Equation is
Balanced
NaHCO3 + CH3COOH → CO2
+ H2O + Na+ + CH3COO-

58. Baking soda + Vinegar
NaHCO3 + CH3COOH →

59. Baking soda + Vinegar
NaHCO3 + CH3COOH →
Na= with how many atoms may it
react?
H= with how many atoms may it react?
C= with how many atoms may it react?
O= with how many atoms may it react?