USING ENGLISH TO SHOW CAUSE AND EFFECT OF CHEMICAL REACTION (resume 3)

Chemical reaction is a change that produces new substances. New substances produced there are those who can return to their original form and some are not able. 
Causes of chemical reactions: 
1. Occurs due to burning. 
2. Occurs due to mixing of substances.
 3. Occurs due to the flow of electricity. 
The chemical reaction equation is written as follows:
 
A and B as reactantC and D as reaction product.In the reaction equation there is a symbol of the form of substance: s (solid), aq (aqueous), l (liquid) and g (gas).
 
Characteristics of chemical reactions:
1. Making gas 
2. Formation of precipitate 
3. Discoloration 
4. Temperature changes 

Various kinds of chemical reactions: 
1. Decomposition 
2. Oxidation
3. Reduction 
4. Neutralization 
5. Precipitation 
6. Exchange 
7. Fermentation 
How to control the speed of the reaction can be done by changing: 
1. Reaction temperature 
2. Concentrations of reagents 
3. Touch surface area 
4. Catalyst 

Chemical Reactions in Everyday Life 
1. Corrosion 
2. Decomposition of food 
3. Fireworks 

Division of Material Properties 
Based on substance size: 

1. Intensive Properties. Properties that are not affected by the size of the substance. Example: color, density, freezing point, etc.
2. Extensive properties. Properties that are affected by the size of the substance. Example: volume, length, mass, etc.

Based on the ability of substance 

1. Physical properties. Properties that can be observed without changing the identity of the substance.    Example: melting point, boiling point, heat conductivity, electric conductivity, density, hardness level etc. 
2. Chemical properties. Properties related to the ability of the substance to react to form other substances. Example: the ability of a substance to react with oxygen, water, acid etc.

  

"CHEMICAL CHANGE"

Chemical change is a change that changes the identity of matter in a matter. In the chemical change formed a new substance. The occurrence of a chemical reaction can be known from the changes caused by the reaction. Some of these changes are the formation of sediment, the occurrence of color changes, the formation of gas, and the presence of temperature changes. 

1. Chemical Reactions Produce Sludge 
Around us there are many chemical reactions that can produce sediment. Reactions that include examples of chemical reactions that produce precipitates include: Occurrence of carbonate compounds at the bottom of the pan when boiling water. When lime water is blown, there will be a reaction between lime water and carbon dioxide from the breath. The occurrence of the reaction can be observed the formation of white calcium carbonate (CaCO3) that settles on the bottom of the glass if left for a while. Precipitation by chemical reactions has long been used for water purification processes. The muddy well water mixed with mud can be clarified with the addition of alum. Tawas will tie the particles of mud particles to clot and eventually settle.

2. Chemical Reactions Produce Color Changes 
Apples that are cut and left for a while, over time will be turn brown. This color change indicates that the chemicals in apples have reacted with oxygen in the air. The reaction between the starch starch solution with iodine tintur can be known from the color change that occurs. Color clear starch solution, brown iodine. If both are mixed will form a blue color. If added vitamin C then iodine will react with vitamin C to form other chemicals that are colorless. So the occurrence of chemical reactions can be known from the color changes that occur. Household tools made of metal, these objects will gradually change color. The tool of iron will rust so that it becomes black, copper tools will change color to greenish, the tool from silver will change color to black. The color change indicates that there has been a chemical reaction to the devices. The color of the clothes we wear will fade as it reacts with the chemicals contained in the detergent.

3. Chemical Reactions Produce Gas 
In everyday life, many of us encounter marked chemical reactions with the formation of gas. When the carbide is mixed with water, it will produce carbide gas. This gas is generally used for purposes metal welding. In addition, carbide gas can also used to speed up the ripening of the fruit. When making a cake, into the dough is added baking soda. As the dough is heated, baking soda will break down producing carbon dioxide gas. Gas is what causes the cake to expand.

4. Chemical Reactions Produce Temperature Changes    
A firecracker explosion is the result of a chemical reaction. All reactions always involving energy, some reactions absorb energy and some are releasing energy. The energy that accompanies the chemical reaction is heat, light, sound, or electrical energy. A chemical reaction that produces energy is called an exothermic reaction. If the energy is hot, it can tell by measuring its temperature rise. The combustion reaction is an example of an exothermic reaction. When reacting with water, we can feel the increase the temperature on the glass wall where the reaction is performed. Large temperature rise can measured with a thermometer. A chemical reaction that requires energy called endothermic reactions. For example, a reaction to the photosynthesis process.

Chemical change is a change in substances that produce new substances with new properties, which are called chemical reactions. The change of substance can not return to its original form. Characteristics of chemical changes of a substance, namely:The formation of a new type of substance, followed by changes in chemical properties through chemical reactions, and substances that have changed can not return to their original form.During chemical changes, the mass of the substance before the reaction is the same as the mass of the substance after the chemical reaction. 

The occurrence of chemical changes caused by: 

1. Occurs due to combustion 
2. Occurs due to mixing of substances 
3. Occurs due to the flow of electricity 
4. Occurs due to mixing of two or more substances

Some examples of chemical changes: 

1. Apples that rot  
2. Paper burned to ashes 
3. Compost fertilizer in the process of dried leaves 
4. Burning of gasoline on motor vehicles 
5. Stale rice 
6. Photosynthesis 
7. Soybeans are made in the manufacture of tofu and tempeh 
8. Meat is roasted into satay 
9. Burning wood sticks into charcoal 
10. Eat eating and in process in the body of living things into feces / faeces) 
11. White skin becomes black because most are sunbathing under the heat of sunlight 
12. Milk becomes sour due to the formation of a new substance, namely lactic acid 
13. Exploding firecrackers produce different shapes in their original shape 
14. Potatoes and apples that have been peeled in let for a few seconds, will produce a color brown spots.
15. Iron becomes rust, iron Fe becomes Fe2O3 different from iron
16. Cassava made into tapai produces different shapes and flavors Sample of Chemical Change 
17. Sugar is heated to liquid 
18. The process of purifying gold using mercury 
19. Mixing acids and bases into salts and solvents 
20. The formation of red blood cells in the bone marrow