using english to explained about chemical reaction
Understanding Chemical
Reaction
Chemical
reaction is an event of chemical change from substances that react (reactants)
to reaction products (products). In this chemical reaction is always produced
new substances with new properties. This chemical reaction is written using
elemental symbols.
Characteristics of
Chemical Reactions
A chemical change or
chemical reaction can be known through the accompanying symptoms. The symptoms
or characteristics of chemical reactions include the following:
1.
Color changes occur.
2.
The occurrence of gas
3.
Sludge occurs
Deposition
of the reaction results can be found in cooking tools. It can also be found in
a water purification process that uses alum.
4.
Temperature changes occur
A
temperature change can be observed when limestone is mixed with water. In
addition you can also find a change in temperature in the reaction of carbide
with water.
Chemical
Reactions
To facilitate the conduct of a chemical
reaction activity, then grouped chemical reactions are based on the similarity
possessed. One of these classification systems is based on the way the atoms
are reconstituted in chemical reactions, including:
1.
Reaction Reaction
Ie in the reaction of combining two or
more substances together to form another substance.
For
example: on the reaction between hydrogen and oxygen that make up water
2.
Decomposition Reactions
The decomposition reaction is a reverse
reaction of the coupling reaction. In this reaction one substance is split or
decomposes into two or more simpler substances. Most of these reactions require
an energy of heat, light, and electricity. The general formula for this decomposition
reaction is as follows:
For
example: The reaction of the decomposition of water by electricity produces
hydrogen and oxygen.
3.
Reaction Reaction
The replacement reaction is a single
replacement reaction occurs, when one element replaces another in one compound.
To solve the replacement reaction equation there are two equations, as follows:
For
example: A copper wire is inserted into a silver nitrate solution. Copper is
more active than silver, so the copper that replaces silver forms a blue copper
(II) nitrate solution.
If the chemical reaction is very slower to be reaction,what should we do to make the chemical reaction more fast and we can known through the accompanying symptoms?
BalasHapusFACTORS THAT INFLUENCE THE REACTIONS
HapusSurface area
The touch surface area between the reacting substances is a factor affecting the reaction rate for heterogeneous reagent mixtures, for example between solids and gases, solids with solutions, and two non-mixed liquids. Chemical reactions may take place if the molecules, atoms, or ions and reactants first collide. This happens when the substances that will react occur contact.
The more the touch surface area between the reacting substances, the more the colliding molecules and the quicker the reaction.
In the reaction between a solid and a gas or between a solid and a solution, contact occurs on the surface of the solid. The contact that occurs between two non-mixing liquids occurs in the boundary plane between the two kinds of liquids.
2. Different types of chemical bonds present in various compounds also determine the difference in reaction rate that occurs when the compounds react. Generally, ionic compounds react more quickly than covalent compounds. For example, the reaction between AgNO3 and HCl solution proceeds faster than the reaction between Na2S2O3 and HCl solutions. In the reaction between AgNO3 and HCl solutions, the Ag + and Cl- ions immediately bond together to form AgCI white precipitate. This is because between the ions opposite the charge there is an electric attraction that helps the collision. In the reaction between Na2S2O3 and HCl solution, the occurrence of white sediment and sulfur is slow. The reaction between H + and S2O32 ions to H2S2O3 is rapid, but the precipitate does not result from the reaction between the ions. Sulfur precipitates occur due to the covalent bond termination reaction in the H2S2O3 molecule that takes place.
Ag + (aq) + Cl- (aq) → AgCI (s) (fast)
2H + (aq) + S2O32- (aq) → H2S2O3 (aq) (fast)
H2S2O3 (aq) → H2O (l) + SO2 (g) + S (s) (slow)
The reaction of covalent compounds takes place more slowly than the ionic compounds because in the covalent compound there is no electric attraction between the particles. In addition, it also takes some energy to break the covalent bond and the reacting compound.
If one of the chemical reaction characteristics does not exist whether it can still be called a chemical reaction ?
BalasHapusYes..
HapusA chemical reaction occurs when between the mixed substances form a new substance with a chemical bond. The existence of chemical bonds cause the substance formed to have properties that are much different from the material pemben-tuknya. Some examples of chemical reactions that we often encounter in everyday life are garbage decay, paper burning, burning wood, iron rods due to humid air, water degradation into oxygen gas and hydrogen gas in electrolysis events, and so on.
B. Features of Chemical Reaction
Ongoing chemical changes or chemical reactions are typically characterized by observable changes, for example by the appearance of discoloration due to the occurrence of new substances, the formation of deposits, the occurrence of gases, and the presence of temperature changes. The following characteristics of the occurrence of a chemical reaction with an example.
1. The emergence of Gas bubbles
Figure 11.4 The appearance of bubbles is one of the characteristics of the occurrence of substances of a new type
Example:
Iron metal with hydrochloric acid solution produces hydrogen gas.
Fe (s) + 2HCI (aq) -> FeCI2 (aq) + H2 (g)
Zinc metal + hydrochloric acid solution, also produces hydrogen gas.
Zn (s) + 2HC \ (aq) -> ZnCI2 (a Pbl2 (s) + 2CH3COOK (a <7)
A solution of silver nitrate with sodium chloride, forming a white precipitate.
AgN03 (3 <7) + NaCI (a <7) - »AgCI (s) + NaN03 (aq)
3. Color Changes occur
Figure 11.6 The clear initial hydrochloric acid (HCl) solution turns yellowish after being treated with ferrous metals
Example
Potassium permanganate solution of red-purple will become clear or pink if it is spilled with sulfuric acid (H2S04) and oxalic acid (H2C204).
2knn04 (aq) + 5H2C04 (aq) K2S04 (ac7) + 2MnS04 (a <7) + 8H20 (l) + 10CO2 (g)
Iron metal with a solution of hydrochloric acid will produce hydrogen gas and a yellowish-colored iron chloride solution.
Fe (s) + HCI (aq) FeCI2 (aq) + H 2 (g)
4. Temperature Changes
Figure 11.7 Limestone becomes hot when added to water due to chemical reactions
Example:
The solution of barium oxide (BaO) with ammonium chloride (NH4CI), causes a decrease in temperature.
BaO (aq) + 2NH4CI (a <7) -> BaCI2 (a <7) + 2NH3 (a <7) + H20 (/)
Crystalline calcium oxide (CaO) with water (H20), causes a rise in temperature.
CaO (s) + H20 (/) -> Ca (0H) 2 (ag)
How is the process of purifying water using alum?
BalasHapusWater Treatment Mechanism at PDAM:
Hapus1. River water is pumped into pre-sedimentation basin. In this pre-sedimentation basin the sludge is allowed to settle due to the influence of gravity. The sludge is disposed of with the pump.
2. Then the water still contains mud particles that are so small that they can not settle because the influence of gravity is channeled into the ventury tub. At this stage water is mixed with Al2 (SO4) 3. 18 H2O (alum). The Al3 + ion present in alum will be hydrolysed to form a positive Al (OH) 3 colloidal particle by reaction:
Al3 + + 3 H2O → Al (OH) 3 + 3H +
The formed Al (OH) 3 absorbs clumps and precipitates. Ion Al3 + will remove negative charges from colloid particles such as clay / mud, so that small sized mud into large flocs (coagulation). The mud is then settled along with the alum due to the influence of gravity. In addition to functioning so that mud is easier to settle coagulation also aims to facilitate the mud to be filtered. In addition, alum that forms colloid Al (OH) 3 can also adsorb dyes or substances such as detergents and pesticides.
Furthermore, chlorine gas (preechlorination), which acts as a disinfectant and activated carbon (if the water turbidity level is high). Activated carbon is used to remove odor, taste, and organic substances contained in raw water.
3. Half-clean water is then flowed into a sand filter. From the sandbox water is obtained almost clean, because the remaining floc will be retained by a sand filter.
4. The water in the sandbox is flowed into the siphon. In an almost clean siphon water is added chalk to raise the pH and chlorine gas (post chlorination) to kill the pests.
5. Water that meets the clean standard from siphon tub to the reservoir.
6. Water ready for consumer consumption
The clean water treatment process in the water treatment industry (PDAM) described above is referred to as conventional drinking water treatment system.
Substances reacting (reactants) into reaction products (products). In this chemical reaction is always produced a new substance with new properties give an example?
BalasHapusChanges in substances that give rise to new substances are called chemical changes. In chemical reactions, there are two components involved in a chemical reaction, ie substances before reaction and substances after reaction. The reacting substances are called reactants (reactants) and the resulting substances are called reaction products (products).The reactant (reactants) is located to the left of the arrow sign, while the product is located on the right (arrow sign). This relationship can be written as follows.
HapusReagents + reagents ---> reaction products
Reactants + reactants ---> products
An example of a reaction equation is
Mg (s) + 2 HCl (aq) ---> MgCl2 (aq) + H2 (g)
Reagents / Reagents / Reaction Results / Reaction Results /
Reactant product reactants
Can you give a description of this phrase "Can also be found in the process of purification of water using alum." With examples.
BalasHapus