The document discusses chemical reaction equations. It defines a chemical reaction as a chemical change indicated by sedimentation, gas formation, or color change. It explains that a chemical reaction equation names the reactants and products using atomic symbols and balances the number of each atom on both sides of the equation using methods like trial and error or setting up mathematical equations. It provides examples of balancing equations for reactions like magnesium and oxygen forming magnesium oxide, and hydrogen and oxygen forming water.

1. Chemical Reaction Equation
Viandhika Ditama, S.pd

2. Definition chemical reaction
Also called the chemical change.
Indication :
1.sedimentation
2.Gas forming
3.Color change.

3. Naming the chemical reaction
equation
Generally,reaction equation is described as
follow :
aA (a) + bB(b) →cC (c) + dD (d)

4. Naming the chemical reaction
equation
The following step in writing a chemical reaction
equation:
1. Determine the reactants and the products
2. Write the atomic symbol of each substance
3. Write the symbol of (+) and (→)
4. Balance the number of each atom in both left
and right sides.

5. Naming the chemical reaction
equation
The reaction between potassium metal and
chlorine gas can be decribed into chemical
reaction as follow
2K (s) + Cl2(g) →2KCl(s)

6. Balancing the chemical
equation
1. Trial method
Mg (s) + O2(g) →MgO(s)
Mg (s) + O2(g) →2MgO(s)
2Mg (s) + O2(g) →2MgO(s)

7. Balancing the chemical
equation
Example :
Na (s) + H2O(l) →2NaOH(aq) + H2(g)
2Na (s) + H2O(l) →2NaOH(aq) + H2(g)
2Na (s) + 2H2O(l) →2NaOH(aq) + H2(g)
2Na (s) + 2H2O(l) →2NaOH(aq) + 2H2(g)

8. Balancing the chemical
equation
2. Mathematical equation method
aMg (s) + bO2(g) →cMgO(s)
To equalize Mg atom : a = c
To equalize O atom : 2b = c
For instance, b=1, then c=2
Add the a,b,and c value into the equation
2Mg (s) + O2(g) →2MgO(s)

9. Balancing the chemical
equation
Example :
H2 (g) + O2(g) →H2O(l)
To equalize H atom : a = c
To equalize O atom : 2b = c
For instance, a=1, then c=1
2b=c
2b=1
B=1/2
Add the a,b,and c value into the equation
H2 (g) + ½ O2(g) →H2O(l)