1. S2 Chemistry
Equations

2. Word Equations
Learning Intention We are learning to write word equations

3. Word Equations
All chemical reactions can be described using a word equation eg reactants products (what you start with) (what you end up with)

4. Word Equations
eg magnesium + oxygen magnesium oxide

5. Word Equations
Write a word equation for the following reaction

6. Word Equations Write a word equation for the following reaction
Carbon dioxide is formed when carbon burns in oxygen.

7. Word Equations Write a word equation for the following reaction
Carbon dioxide is formed when carbon burns in oxygen.
carbon + oxygen carbon dioxide

8. Formula Equations
Learning Intention We are learning to write formula equations

9. Formula Equations
Instead of using words, the formula for the reactants and products can be used instead. This is called a formula equation.
carbon + oxygen carbon dioxide

10. Formula Equations
Instead of using words, the formula for the reactants and products can be used instead. This is called a formula equation.
carbon + oxygen carbon dioxide
C O2 CO2

11. Formula Equations Eg
hydrogen + oxygen hydrogen oxide

12. Formula Equations Eg
hydrogen + oxygen hydrogen oxide
H2 + O2 H2O

13. Diatomic Elements
Certain elements always go around in pairs. These are the diatomic elements.

14. Diatomic Elements
Certain elements always go around in pairs. These are the diatomic elements.
H2, O2, N2, F2, Cl2, Br2, I2

15. Diatomic Elements
Certain elements always go around in pairs. These are the diatomic elements.
H2, O2, N2, F2, Cl2, Br2, I2
In formula equations they must always be written as pairs.

16. Balancing Equations
A balanced equation is when the number of each element on the product side equals the number of each element on the reactant side.

17. Balancing Equations Eg
C O2 CO2
This is balanced.

18. Balancing Equations Eg
H2 + O2 H2O

19. Balancing Equations Eg
H2 + O2 H2O
This is not balanced.

20. carbon + chlorine
C + Cl2 CCl4

21. carbon + chlorine
C + Cl2 CCl4 C C Cl Cl

22. carbon + chlorine
C + Cl2 CCl4 C 1 C 1 Cl 2 Cl 4

23. carbon + chlorine
C + 2Cl2 CCl4 C 1 C 1 Cl 4 Cl 4

24. Combustion of Methane
CH4 + O2 CO H2O C C H H O O

25. Combustion of Methane
CH4 + O2 CO H2O C 1 C 1 H 4 H 2 O 2 O 3

26. Combustion of Methane
CH4 + O2 CO H2O C 1 C 1 H 4 H 4 O 2 O 4

27. Combustion of Methane
CH O2 CO H2O C 1 C 1 H 4 H 4 O 4 O 4

28. Calculations from Equations
C O2 CO2

29. Calculations from Equations
C O2 CO2
12g

30. Calculations from Equations
C O2 CO2
12g 32g

31. Calculatios from Equations
C O2 CO2
12g 32g 44g

32. Calculations from Equations
C O2 CO2
12g 32g 44g
6g 16g 22g

33. Calculations from Equations
C O2 CO2
12g 32g 44g
6g 16g 22g
1.2g 3.2g g