VIDEOS ENGLISH NARRATION

PH

https://www.youtube.com/watch?v=HxSHx0Z_7pE 

 

               PH is the degree of acidity used to express the level of acidity or alkalinity possessed by a solution. It is defined as the soluble hydrogen ion (H +) activity kologarithm. The hydrogen ion activity coefficient can not be measured experimentally, so its value is based on theoretical calculations. The pH scale is not an absolute scale. It is relative to a set of standard solutions whose pH is determined by international agreement. [1] The pH concept was first introduced by Danish chemist Søren Peder Lauritz Sørensen in 1909. It is not known exactly the meaning of the abbreviation "p" in "pH". Some references indicate that p is derived from the abbreviation for powerp [2] (rank), others refer to the German word Potenz (which also means rank) [3], and others refer to the word potential. Jens Norby published a paper in 2000 arguing that p is a constant meaning "negative logarithm" [4]. Pure water is neutral, with its pH at 25 ° C set as 7.0. Solutions of less than seven pH are called acidic, and solutions with a pH of more than seven are said to be alkaline or alkaline. PH measurements are essential in areas related to life or chemical processing industries such as chemistry, biology, medicine, agriculture, food science, engineering (engineering), and oceanography. Of course other fields of science and technology are also wearing even in lower frequencies.

Concept maps

A. Properties of Acids, Bases, and Salt

               The term acid (acid) comes from Latin acetum which means vinegar. As is known, the main substance in vinegar is acetic acid. Basa (alkali) is derived from Arabic which means ash.

As with soap, bases are caustic, but alkaline is also alkaline (reacts with proteins in the skin so skin cells will undergo alternation). Bitter taste is one of the properties of alkaline substances.

We can recognize acids and bases of taste. However, we are forbidden to recognize acid and base by tasting because it is not a safe way. To identify good and safe acid and base by using indicator. Indicator is a material that can react with acid, base, or salt so that will cause the color change.

1. Acid

               Acid is one of the ingredients of various foods and beverages, such as vinegar, cheese, and fruits. According to Arrhenius, acid is a substance that in water will release H + ions. Thus, the acid carrier is an H + ion (hydrogen ion), so the acidic chemical formula always contains a hydrogen atom. Ions are atoms or groups of electrically charged atoms. Cations are positively charged ions. The anions are negatively charged ions.

               Another characteristic of the acid is that it can react with various materials such as metals, marble, and ceramics. The reaction between acids and metals is corrosive. For example, ferrous metals can react quickly with hydrochloric acid (HCl) to form Iron (II) chloride (FeCl2).

Table of some examples of acids

Table of Life Acid Everyday

               Based on the origin, acid is grouped into 2 groups, namely organic acids and inorganic acids. Organic acids are generally acidic, corrosive, and widely present in nature. Inorganic acids are generally strong and corrosive acids. Because of its properties that, inorganic acids are widely used in various human needs.

Fruit that is Acidic

2.Basa

               In pure state, the base is generally a solid crystal and is caustic. Some household products such as deodorants, ulcer drugs (antacid) and soaps and detergents contain bases.

A base is a compound which, when dissolved in water (solution) can release hydroxide ions (OH-). Therefore, all basic chemical formulas generally contain OH groups.

If it is known the chemical formula of a base, then to give the name of a base, simply by mentioning the metal name and followed by the word hydroxide.

Table Bases of Everyday Life

Differences of Acid and Base Properties

Differences of Acid Base Properties

3. Salt

               People experience abdominal pain due to increased stomach acid. To neutralize stomach acid (HCl) is used antacid. Antacids contain bases that can neutralize excess stomach acid (HCl).

               Generally substances with opposite properties, such as acids and bases tend to react to form new substances. When the acid solution is reacted with the basic solution, then the H + ions of the acid will react with the OH-ions from the base to form water molecules.

H + (aq) + OH- (aq) -> H2O (ℓ)

Acid Water Base

               Since water is neutral, the acidic reaction with a base is called a neutralizing reaction.

These ions will combine to form ionic compounds called salts. If the salt formed is easily soluble in water, then the ions will remain in the solution. But if the salt is difficult to dissolve in water, the ions will combine to form a precipitate. Thus, acidic reactions with bases are also called salting reactions due to forming salt compounds. Let's look at an example of the following salt formation reaction!

Acid + Basa -> Salt + Water

Acid chloride + Sodium hydroxide -> Sodium chloride + water

HCl (aq) + Na OH (aq) -> Na Cl (aq) + H2O (ℓ)

Acid            Base                Salt            water 

               Although acidic reactions with bases are called neutralizing reactions, but the reaction product (salt) is not always neutral. The acid-base properties of the salt solution depend on the strength of the acid and its constituent base.

Salt derived from strong acids and strong bases are neutral, called normal salts, for example NaCl and KNO3. The salts derived from strong acids and weak bases are acidic and are called acid salts, for example is NH4 Cl. The salts derived from weak acids and strong bases are alkaline and are called alkaline salts, for example CH3COONa. Examples of strong acids are HCl, HNO3, H2SO4. The KOH, NaOH, Ca (OH) 2 include strong bases.

Table a few examples of salt

4. Acid Solutions, Bases, and Salt are Electrolyte

               When someone is looking for a fish by using "stun" or electric current coming from the battery, what happens after a while the tip of the electrically grounded device is immersed in the river water? Apparently the fish around the tip of the tool was exposed to electricity and fainted or died.

Is water able to conduct electricity?

Actually, pure water is a poor conductor of electricity. However, when dissolved acid, base, or salt into the water then this solution can conduct electrical current. Substances that dissolve in water and can form a solution that conducts an electric current is called an electrolyte solution. An example is a solution of a kitchen salt and a solution of hydrochloric acid. Substances that do not conduct electricity are called nonelectrolyte solutions. Examples are sugar and urea solutions.

To know a solution can conduct an electric current or not, it can be tested with an electrolyte tester. A simple electrolyte tester consists of two electrodes connected to an electric current source and fitted with a lamp, as well as a vessel containing the solution to be tested. Let us do the following activities to find out whether the acid, base, and salt can conduct an electric current.

B. Identification of Acids, Bases, and Salt

               Lots of solutions around us, whether acidic, alkaline, or neutral. How to determine the acid and base properties of the solution appropriately using indicators. The indicator that can be used is acid-base indicator. Indicators are substances that show different indications in acid, base, and saline solutions. How to determine acidic, alkaline or neutral compounds can use litmus paper and a solution of natural indicators or indicators.

Here are some ways to test the properties of the solution.

1. Identify with Lakmus Paper

               The color of litmus paper in acid solution, base solution and solution are different neutral. There are two kinds of litmus paper, the red litmus and the blue litmus. The properties of each of these litmus papers are as follows.

A. The red lobster in the red acid solution and in the blue base solution.

B. The blue lantern in the acid solution is red and in the blue base solution.

C. Both red and blue lacquers in neutral solutions do not change color.

Identification of Lakmus Paper

2. Identify Acid and Base Solutions Using Natural Indicators

               Another way to identify the acid or base properties of a substance can be to use natural indicators. Various colored flowers or plants, such as leaves, flower crown, turmeric, mangosteen peel, and purple cabbage can be used as acid-base indicator. Extracts or essences of these ingredients can show different colors in acid-base solutions.

Natural Indicators

               For example, take the skin of mangosteen, mash until smooth and mix with a little water. The color of the mangosteen skin is purple (in neutral). If the mangosteen skin extract is divided into two and each is dripped with acid and base solutions, then in acid solution there is a change of color from purple to reddish brown. The dripping base solution will change the color from purple to dark blue.

C. Determination of the Scale of Acidity and alkalinity

1. The Power of Acid and Bases

               The strength of an acid or base depends on how the compound can be decomposed into ions in water. The event of the decay of a substance into its ions in water is called ionization. Perfectly ionized acids or bases in solution are strong acids or strong bases. In contrast, the acid or base which is only partly ionized is a weak acid or a weak base.

               If you want to know the strength of acid and base so can be done simple experiment. Notice the flashing light during the experiment of electrolyte solution test. If the flame dim light means a solution classified as acid or weak base, otherwise when a bright light flame means the solution is classified as acid or strong base.

Test of Acid Base Strength

Strong acids or weak acids at the same concentration conduct different electricity. The lamplight in Fig. (A) appears dim. This means the tested solution is a weak acid or a weak base. As in Fig. (B) the lamp is brightly lit, indicating that the tested solution is a strong acid or a strong base.

2. Degree of acidity and alkalinity (pH and pOH)

Basically the degree / acidity of a solution (pH = potenz hydrogen)) depends on the concentration of H + ions in the solution. The greater the concentration of H + ions the more acidic the solution is.

Generally the concentration of H + ions in the solution is very small, so to simplify the writing is used the concept of pH to express the concentration of H + ions. The pH value is equal to the negative logarithm of the concentration of H + ions and is mathematically expressed by the equation

 Strong acids

[H+] = a . ma

Weak acid

[H+] =  

 [H+] = α . Ma

The pH formula

pH = – log (H+)

Analogue with pH, ​​OH-ion concentration can also be expressed in the same way, ie pOH (Potenz Hydroxide) expressed by the following equation.

 Strong acids

[OH-] = b . mb

Weak acid

[OH-] =  

 [OH-] = α . Mb

The pH formula

pOH = – log (OH-)

The degree of acidity of a substance (pH) is shown on a scale of 0-14.

A. Solutions with a pH <7 are acidic.

B. Solutions with pH = 7 are neutral.

C. Solutions with pH> 7 are alkaline.

The pH value and pOH = 14. For example, a solution has a pOH = 5, then the price pH = 14 - 5 = 9. The pH value for some of the substances we can find in the daily environment is expressed in Table.

Table Price pH for Some Type of Substance

The salt hydrolysis formula

Acid

[H+] =                           [G] =  

Base

[OH-] =                           [G] =  

3. Determining the pH of a Solution

               The degree of acidity (pH) of a solution can be determined using the universal indicator, indicator stick, indiactor solution, and pH meter.

A. Universal Indicators.

               The universal indicator is a mixture of various indicators that can indicate the pH of a solution of the color change. Universal indicator there are two kinds of indicator in the form of paper and solution.

B. Paper Indicator (Stick Indicator)

               Paper indicator is absorbent paper and each packing box of this type indicator is equipped with color map. Its use is very simple, an indicator dipped in the solution to be measured its pH. Then compared to the available color map.

Universal Indicators

C. Indicator Solutions

One example of a universal indicator of this type of solution is the methyl orange solution (Methyl Orange = MO). At pH less than 6 this solution is orange, while at pH more than 7 colors become yellow.

Acid Alkaline Solution

Indicator Solutions

Another example of liquid indicators is the phenolphthaline indicator (Phenolphtalein = pp). PH below 8, phenolphthaline is colorless, and will be red wine when the pH of the solution is above 10.

D. PH meter

Testing of acid-base acid properties can also use pH meter. The use of this tool by immersion in the solution to be tested, at pH meter will appear scale number indicating pH of solution.

PH meter digital

PH meter elektronik

RPP CURICULUM 2013

LESSON PLAN

Name of School: SMAN 1 DREAM

Subject: CHEMICAL

Class / Semester: XI / 2

Meeting to: 1

Time allocation: 1 x 20 minutes

A.    CORE COMPETENCY

KI 1    : Understanding, applying, analyzing factual, conceptual,   procedural       knowledge based on curiosity about science, technology, art, culture and humanities with humanitarian, national, state, and civilization insights on the causes of phenomena and events, and applying procedural knowledge In a specific field of study according to his or her talents and interests to solve the problem.

KI 2    : Processing, reasoning, and recruiting in the realm of concrete and abstract realms related to the development of self-study in schools independently, and capable of using methods according to scientific rules.

KI 3    : Living and practicing the religious teachings it embraces.

KI 4    : Living and practicing honest, disciplined, responsible, caring (polite, cooperative, tolerant, peaceful) behavior, courteous, responsive and proactive and showing attitude as part of the solution to problems in interacting effectively with the social environment and Nature and in placing ourselves as a reflection of the nation in the association of the world.

B.     BASIC COMPETENCY

3.15 Analyzing the role of colloids in life by virtue of its properties

4.15 Asking ideas / ideas to modify colloid-making based on the experience of making several colloidal types.

1.1 Recognizing the regularity of hydrocarbons, thermochemicals, reaction rates, chemical equilibrium, solutions and colloids as a manifestation of the greatness of God and the knowledge of such order as the result of creative human thought which is tentative.

2.2 Demonstrate cooperative, courteous, tolerant, cintadamai and care about the environment and thrifty in utilizing natural resources.

2.3 Demonstrate responsive and pro-active and prudent behavior as a form of problem-solving ability and decision-making

C. INDICATORS

§  Indicators for KI-1

1. Explain about colloids, suspensions and solutions.

2. Analyzing the role of colloids in life by virtue of its nature.

§  Indicators for KI-2

1. Submit an idea or idea to modify colloid-making based on the experience of making several colloidal types.

§  Indicator for KI-3

Recognizing the presence of the nature of hydrocarbons, thermochemicals, reaction rates, chemical equilibrium, 

solutions and colloids as a manifestation of the greatness of God YME and knowledge of the existence of such 

regularity as the result of human creative thought that the truth is tentative.

·         Indicators for KI-4

1.      show responsive behavior and proactive and wise as a form of problem-solving ability and make decisions.

2.       Shows the behavior of cooperation, courteous, tolerant, cintadamai and care for the environment and efficient

 in utilizing natural resources.

D. LEARNING OBJECTIVES

1.      Students can explain the meaning of colloids, suspensions and solutions well.

2.      Students can name the properties of the colloids, suspensions and solutions properly and correctly.

3.      Students can distinguish colloids with suspensions and solutions based on their properties properly and correctly.

4.      Students can cite samples of colloid, suspension and solution properly and correctly.

5.      Students may group or classify the compounds into groups of colloids, suspensions and / or solutions appropriately.

6.      Students are able to analyze the role of colloids in life based on their nature.

7.      Students can explain the colloid manufacture that has been known well and correctly.

8.      Students are able to propose ideas or ideas to modify colloid-making based on the experience of making some colloid 

       species communicative and polite.

9.      Train students to always be grateful to the God Almighty.

10.  Train students to demonstrate the behavior of cooperation, courteous, tolerant, cintadamai and care for the environment

 and efficient in utilizing natural resources.

11.  Train students to behave responsively and proactively and wisely as a form of problem-solving ability and decision making.

A. MATERIAL

A. Colloidal System Components

Colloids are a mixture of heterogeneous substances (two phases) between two or more substances in which the colloidal particles of matter (dispersed / dispersed phases) are spread evenly in other substances (dispersing medium). The size of colloidal particles ranges from 1-100 nm. Thus, colloids are a heterogeneous mixture and are two-phase systems. Thus, the colloidal system is composed of two components, namely the dispersed phase and the dispersion medium or dispersing phase.

- The dispersed phase is discontinuous (discontinuous)

- Medium dispersion is continuous.

B. Grouping of Colloid Systems

Phase Dispersed	Phase Dispersing	System Colloids	Example
Gas	Cair	Foam / foam	Soap foam
Gas	Solid	Solid foam	Pumice stone, lava
Liquid	Gas	Aerosol	Fog, cloud, spray
Liquid	Liquid	Emulsion	Milk, fish oil, sauces
Liquid	Solid	Gel (solid emulsion)	Cheese, butter, jam, jelly, solid polish, pearls
Solid	Gas	Solid aerosols	Smoke, dust, exhaust effluent
Solid	Liquid	Soles	Kanji, glue paint, ink, latex, egg white
Solid	Solid	Solid soles	Bronze, brass, colored glass, gems (gem)

C. Colloidal Properties

1. Tyndall effect

               This tyndall effect was discovered by John Tyndall (1820-1893), a British physicist. Therefore it is called the tyndall effect. The tyndall effect is the effect that occurs when a solution is exposed to light. When the true solution is irradiated with light, the solution will not scatter light, whereas in the colloidal system light will be dissipated. This happens because colloidal particles have relatively large particles to scatter them. In contrast, in the true solution, the particles are relatively small so that the scattering occurs only slightly and is very difficult to observe.

2. Brownian motion

               If we observe the colloidal system under an ultra microscope, then we will see that the particles will move to form a zigzag. This zigzag movement is called Brownian motion. The movement is described in the following explanation: The particles of a substance are constantly moving. The movement may be random as in liquids and gases, or simply vibrate in places such as solids. For a colloidal system with a liquid or gas dispersing medium, the movement of particles will result in collisions with the colloid particles themselves. The collision took place from all directions. Because the particle size is small enough, the collisions that occur tend to be unbalanced. So there is a resultant collision that causes changes in the direction of motion of particles resulting in the motion of zigzag or Brownian motion. The smaller the size of colloidal particles, the faster Brownian motion occurs. Similarly, the larger the size of the colopid particles, the slower the Brownian motion takes place. This explains why Brownian motion is difficult to observe in solution and is not found in solids (suspension). Brownian motion is also affected by temperature. The higher the temperature of the colloidal system, the greater the kinetic energy of the dispersed medium particles. As a result, Brown's motion of the dispersed phase particles is accelerating. Similarly, the lower the temperature of the colloidal system, the more slow the Brownian motion.

3.      Elektropresus

               Is a separation technique of charged components or molecules based on their different migration rates in an electric field. The electric field is flown on a medium containing the sample to be separated. This technique can be used by utilizing the existing electrical charge on macromolecules, such as negatively charged DNA. If a negatively charged molecule is passed through a medium, then the electric current flows from a pole to the opposite pole of charge, then the molecule will move from the negative pole to the positive pole. The speed of motion of the molecule depends on the ratio of charge to its mass and also depends on the shape of the molecule. This movement can be explained by Lorentz style, which is related to the fundamental properties of the observed material and the electrical conditions of the environment. In general, electrophoresis is used to separate, identify, and purify DNA fragments.

4.      Adsorption

               When solid particles are placed in liquids or gases, the particles of such liquids or gases will accumulate on the surface of the solid. This phenomenon is called adsorption. Unlike the case with absorption. Absorption is a phenomenon of absorbing all particles into a solid sole not above its surface, but inside the solid sole. Colloidal sol particles have the ability to adsorb particles on their surface, either neutral or charged particles (cations or anions) because they have very large surfaces. Example of adsorption:

-The healing of diarrhea with noritus

- Purifying water with alum

- Wool fiber dyeing for staining process

- Purifying sugarcane juice on sugar making

- Absorption of humus by clay

5. Coagulation

               Coagulation is one of the properties of colloids. The particles of a colloid can become clumped to form a semi-solid substance. The colloid particles are stable because they have similar electrical charges. When the electrical charge is lost, the colloid particles will combine to form a clot. The process of clumping of colloidal particles and its precipitation is called Coagulation. In this case, colloid coagulation is a process of joining colloidal particles together to form substances with a larger mass.

Coagulation Example:

Ø  The establishment of the delta at the mouth of the river occurs because the clay colloids in the river water experience the anticoagulation when mixed with electrolytes in seawater.

Ø  In rubber processing, the rubber particles in the latex are coagulated by the addition of acetic acid or formic acid so that the rubber can be separated from the latex.

Ø  Colloidal mud in river water can be coagulated by adding alum. The clay sole in the river water is usually negatively charged so that it will be clumped by Al 3+ ions from alum (aluminum sulphate)

Ø  If a part of the body is injured then Al 3+ or Fe 3+ ions immediately neutralize the particles of blood contained so that blood clots that cover the wound.

6. Colloid Protector

               The colloidal system in which the dispersed particle has a relatively large adsorption force is called a more stable lyophilic colloid. Whereas if the dispersed particle has a small enough absorption force, it is called a lobefob colloid that is less stable. What functions as a protective colloid is a lyophilic colloid.

Examples of protective colloids:

- In the manufacture of ice cream used gelatin to prevent the formation of large crystals or sugar

-Cat and ink can last long because it uses a protective colloid.

Emulators such as soaps and detergents are also classified as protective colloids.

7. Dialysis

Dialysis is one of the properties of the colloidal system. Dialysis is a process of colloid particle permeation of colloidal disturbing ions by screening using membranes or semipermeable membranes. Semipermeable membrane is a kind of filter tool specially made for the purpose of colloid dialysis that has a very high filter power. This semipermeable membrane passes only water molecules and ions only, while colloidal particles remain. The principle of dialysis or colloidal separation of these intruder ions is based on differences in transport rates of particles. The Colloid Dialysis Process is very simple. The colloid to be in dialysis is inserted into a bag made of semipermeable membrane. If the bag containing the colloid is then inserted into a place filled with running water, the disturbing ions will penetrate the semipermeable membrane with water and the semipermeable membrane is merely a purified colloid.

D. Manufacture of Colloidal System

               The colloidal system can be prepared by two methods, namely by grouping (aggregating) the true particles of the solution and / or refining the coarse material then dispersing into the dispersing medium. The first method is called condensation and the second is called dispersion.

1.      Preparation of Colloid by Dispersion Method

Some practical methods commonly used to make colloids belonging to dispersion are mechanical, peptizing, homogenizing, and redig arc.

A. Colloid Making by Mechanical means

               Substantial substances can be reduced to colloidal-sized particles by grinding, stirring, pounding, and scouring. Subsequently colloidal substances are dispersed into the dispersing medium.

Mechanical way, for example:

·         Soya bean milling on the making of tofu and soy sauce. Manufacture of paint in the industry, the way the paint material is milled and then dispersed into a dispersing medium, such as water.

·         Crushing and stirring techniques are widely used in food making, such as tart and mayonnaise. Egg yolks, margarine, and granulated sugar, then mixed and stirred into colloids.

·         Food industry, which is in the manufacture of ice cream, fruit juice, jam and others. Chemical industry, namely on the manufacture of paints, dyes, toothpaste, and detergents.

B. Colloid Making with Bredig Electrical Bow

               The high-voltage electrical current is passed through two metal electrodes (dispersed material). Then, both electrodes were immersed in water until both ends of the electrode were almost in contact in order to spark an electric spark. The electrical spark jump causes the electrode material to evaporate to form the atoms and dissolve in the dispersing medium to form the soles. The metals that can form soles in this way are platinum, gold, and silver.

C. Making Colloids by Peptisation

               Colloidal dispersions may also be obtained from crude suspensions by breaking chemical suspension particles. Then, adding similar ions can be adsorbed by colloidal particles until the colloid becomes stable. Coagulation of aggregates that have formed colloidal-sized particles can be inhibited because of the ions adsorbed on the surface of colloidal particles. For example, clay breaks into colloid-sized particles when added NaOH and will become colloid if dispersed into water. Silicate particles from clay soil will adsorb OH-ions and form a stable, negatively charged colloid. This method is commonly used on

1.      sol Al (OH) 3 is prepared by adding dilute HCl (slightly) to the newly created Al (OH) 3 precipitate,

2.      sol Fe (OH) 3 is prepared by adding FeCl3 to Fe (OH) 3 precipitate,

3.      3.Sol NiS can be made by adding H2S to NiS precipitate.

D. Making Colloids by Homogenisation

               Preparation of colloidal type of emulsion can be done by using a homogenizer until colloidal sized.

1.       Colloid Making by Condensation Method

Very small ions or molecules (the size of a true solution) are enlarged into colloidal-sized particles. In other words, the true solution is converted to a colloidal dispersion. The formation of mist and clouds in the air is an example of the formation of liquid aerosols through the condensation of water molecules to form a cluster.

A. METHODS, MODELS AND LEARNING STRATEGIES

1. Strategy:

2. Approach: concept

3. Model: TGT

4. Method: discussion.

LEARNING STEPS

ACTIVITIES	TIME	ATTITUDE
Initial activity  : • Greetings • Students are inactive • Present learning indicators and KKM • Divide the students into groups Core activities : Exploration • Convey illustrations about the material. Provides an overview of colloidal function in everyday life. • Provide an opportunity for students to respond to it. Elaboration • Prepare and explain the rules of the game that will be played in relation to the nature of colloid, colloid classification, colloid function and its role in everyday life. • Guiding students in the course of the game so that students can understand the learning of the colloid. Confirmation • Ask for conclusions that can be drawn from game learning • Provide students with opportunities to conclude learning. •              END ACTIVITIES : • Drawing conclusions together. • Teacher assigns homework (PR).	5 ' 10 ' 5 '	Menghormati.Bersyukur kepada Tuhan yang maha Esa.Menghargai. Meningkatkan  rasa ingin tahu. Responsif Aktif. Tanggung jawab. Kreaktif.

G. Learning resources

• Textbook of Chemistry High School publisher erlangga.

• Student Activity Sheet (LKS).

H. Assessment

• Assessment procedures

1. Process assessment:

A. Assessment of student activity in class during learning.

B. Assessment of conformity and accuracy as well as reasoning in communicating the nature, classification, function and role of colloids in everyday life.

2. Product rating: solving problems about colloids.

• Technics: Team game tournament (TGT)

• Assessment tool

1. Learning outcomes in the form of daily test or task (cognitive domain)

2. Student attitude during learning process (affective aspect)

No	Name	Aspect Rating			score
		Seriousness listening and attention	Activity inquiring and discussing class	cooperation
1

1	Sangat baik
2	baik
3	Kurang baik
4	buruk

No	Indikator	question	Assessment
1	Explain the notion of colloids,suspensions and solutions. .	1. Explain what is meant by colloids, suspensions and solutions based on their characteristics and properties! Answer: Colloid is a mixed (dispersion) system of two or more substances that are homogeneous but have a large dispersed particle size (1- 1000 nm). Homogeneous means that the dispersed particles are not affected by the force of gravity or other forces imposed on them; So there is no precipitation. The suspension is a fluid mixture containing solid particles. Or in other words, a heterogeneous mixture of liquids and solids dissolved in the liquid. Solid particles in the suspension system are generally larger than 1 micrometer making it large enough to allow for sedimentation. Unlike colloids, solids in the suspension will undergo sedimentation although there is no disturbance. The solution is a homogeneous mixture which has a non-separating property if it is allowed to stand and has a particle diameter of less than 10-7 cm. The solution can not be filtered but passes the parchment membrane.	If it is possible to describe colloidal, suspension and solution based on its characteristics and properties (each of 3) correctly and accurately the value of 30
2	Classify a compound into the colloids, suspensions and the aqueous solution of its nature.	2.Group the following compounds into colloids, suspensions or solutions: Ink, water and soil mixture, milk, flour water, sugar water, dust, brine, jelly, cough syrup, glue, mist, syrup, cloud, coffee, mayonaise, mud, coconut milk, vinegar, fish oil And shampoo. Answer: 1.                                                                                               solution colloid suspension Sugar water Salt water Syrup vinegar Ink Milk Dust Jelly Glue Fog Cloud Mayonaise Coconut milk Fish oil shampoo Mixture of water and soil Water flour Cough syrup Mud	If the classification is true the score 20 (1 example is worth 1)
3	Analyze the role of colloids in life by virtue of its nature.	3. Many in everyday life can be found colloids that have a very important role for life. Call and explain 2 colloidal functions in everyday life. Answer: Bleaching Sugar Cane-colored sugar cane is bleached. By dissolving the sugar into water, then the solution is passed through the diatomaceous colloidal or carbon dioxide system. The colloidal particles will adsorb the dyestuff. The colloid particles adsorb the dye from the sugar cane so that the sugar can be white. Purifying Water             Current tap water (PDAMs) contain colloidal particles of clay, mud, and other negatively charged particles. Therefore, to make it feasible to drink, steps should be taken to allow the colloid particles to be separated. This is done by adding alum (Al2SO4) 3.Ion Al3 + contained in alum it will dihidroslisis forming particles of colloid Al (OH) 3 which positively charged through reaction: Al3 + + 3H2O à Al (OH) 3 + 3H + After that, Al (OH) 3 removes the negative charges from the clay / mud colloidal particles and coagulates in the mud. The mud is then settled with alum that also settles due to the influence of gravity.	Mention and explain well and correct score 20.