Final Practice About Explanation of Acid and Bases

 ACID AND BASES

A. UNDERSTANDING ACID AND BASES

The acidity and alkalinity of a substance depends on the amount of H + (acid) and OH- (base) ions present in the substance and the degree of ionization of the substance. The acidity and alkalinity of a substance is expressed by pH. In the discussion this time, I will explain about the understanding of acid-base. Material Definition of Acid Bases is very necessary as a foundation of knowledge to understand chemistry materials.

The word "acid" comes from the Latin "acidus" which means sour. Acid is a substance (compound) that causes a sour taste in various materials. Bases are substances (compounds) that can act with acids, producing a compound called salt. While the base is the substances that can neutralize the acid. Chemically, acids and bases are opposite each other. Base properties are generally shown from bitter taste and slippery.

B. THEORY OF ACID AND BASES

1. Arrhenius

Arrhenius put forward a theory of Acid Bases. This theory states that acid is a substance that if dissolved in water will produce H + ions in which this H + ion will be the only positive ion in the solution.

Whereas a base is a substance which, when dissolved in water, ionizes to produce OH-ions, and OH-ions will be the only negative ions in solution.

2. Bronsted-Lowry

Other theories put forward are Bronsted-Lowry Theory which says the acid is a compound that can give protons (H +) to other compounds, while the base can receive protons (H +) from other compounds. The acid-base reaction is the reaction of proton transfer from one compound to another.

3. Lewis

The last theory is Lewis theory which states a base is a substance that has one or more free electron pairs which can be applied to another substance to form covalent coordination bonds, whereas acid is a substance that can accept the pair of free electrons.

 C. ACIDS AND BASIC PROPERTIES

1. The properties of acids are:

·         It tastes sour / sour

·         Corrosive or damaging

·         When dissolved in water can produce H + ions or hydrogen ion ions and negatively charged acidic acid ions. When tested with a blue litmus paper indicator it can turn the litmus red. Whereas if tested with a red litmus paper indicator, the litmus paper will not change color. An indicator is a means to indicate a substance whether acidic or basic.

2. Properties of bases are

·         Bitter taste

·         It is caustic or can damage the skin

·         When dissolved in water may produce OH-ions or hydroxyl ions and metal ions or other negatively charged groups. When the OH ion is almost entirely released or its ionisation is perfect, it includes a strong base or is said to have a low acidity and vice versa.

·         When tested with an indicator in the form of a red litmus, it will change the color of the litmus to blue, while with blue litmus paper, it will not change the color of the litmus paper

D. ACID AND BASE INDICATORS

1. Litmus paper 

One of the most commonly used indicators is litmus paper. There are two types of litmus paper: blue litmus paper and red litmus paper.Red litmus paper will change color to blue when exposed to base, but if exposed to acid or neutral substance then will not change color.The blue litmus paper will turn red when exposed to acid, but if exposed to a base or a neutral substance it will not change color.Paper Lakmus can only compare a substance that includes acid or base, then developed again indicator paper.The universal indicator paper is able to show the acidity and alkalinity of a substance.By comparing the color obtained for each substance tested by the standard paper present in the universal indicator, we can determine the acidity of a substance

2. Indicator of the solution

In addition to litmus paper, and universal indicators, there are also several indicator solutions that are often used in laboratory experiments.

Examples The indicator of this solution is methyl red, methyl orange, bromotimol blue, and several other solutions. This indicator works exactly with litmus paper, this solution will give a color change when exposed to acid or base.

3. Natural indicator

In addition to the common indicators found in the Laboratory, there are several plants around which are able to be indicators when the pH changes.

E. ACID AND BALANCE BALANCE

·        Acid-base buffer systems that immediately combine with acids or bases that will then prevent pH changes or excessive hydrogen ion concentrations.

·     If the hydrogen ion concentration changes, the respiratory center in the brain will be stimulated or stimulated to alter the respiratory rate in the lungs, which will result in changes in the rate of carbon dioxide release from the body that will make the hydrogen ion concentration return to normal.

·         Changes in the concentration of hydrogen ions will also cause the kidneys to remove acidic or base urine depending on what compounds excess, thus helping the concentration of hydrogen ions in the body fluids back nomal.

·      This buffer system can work in a fraction of a second to prevent excessive changes in the hydrogen ion concentration. In contrast the respiratory system takes 1-3 minutes to re-adjust the ionhidrogen concentration after a sudden change. Then the kidney, which is the most powerful acid-base component, takes several hours to more than 24 hours to adjust the hydrogen ion concentration.

here my video : https://www.youtube.com/watch?v=icUjOhx6qtU&t=124s

LEARNING IMPLEMENTATION PLAN (RPP)

 LEARNING IMPLEMENTATION PLAN (RPP)

School                                   : SMAN 2 KERINCI

Subject                                  : Chemistry

Class / Semester                  : X PMS / Odd

Basic Material                     : Atomic Structure Bohr

Time Allocation                  : 3 x 45 Minutes (1 x Meetings)

I.                    Core Competencies:

1.       To live and practice the religious teachings that he embraces

2.       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 and natural environment And in placing themselves as a reflection of the nation in the association of the world.

3.       Understand, apply, analyze factual, conceptual, procedural knowledge based on curiosity about science, technology, art, culture, and humanities with the insights of humanity, nationality, state and civilization on the causes of phenomena and events, and apply procedural knowledge to A specific field of study according to his or her talents and interests to solve problems.

4.       Processing, reasoning, and presenting in the realm of concrete and abstract realms related to the development of the self-study in the school independently, and able to use methods according to scientific rules.

II.                  Basic Competencies and Indicators:

2.1	Recognizing the orderliness of the structure of material particles as a manifestation of the greatness of God YME and the knowledge of the structure of matter particles as the result of human creative thinking whose truth is tentative.
2.2 2.3	Shows scientific behavior (curiosity, discipline, honest, objective, open, able to distinguish facts and opinions, resilient, conscientious, responsible, critical, creative, innovative, democratic, communicative) in designing and conducting experiments and discussions embodied in Everyday attitude. Demonstrate responsive, and proactive and wise behavior as a form of problem-solving ability and decision making.
2.4	Analyzing the atomic structure based on Bohr's atomic theory and the theory of quantum mechanics. 2.4.1. Explains the Bohr atomic theory. 2.4.2. Knowing the electron configuration of Bohr's atomic model 2.4.3. Determine the classes and periods of the Bohr atomic structure.
2.5	Process and analyze atomic structure based on Bohr atomic theory and quantum mechanical theory. 2.5.1. Write down the electron configuration according to Bohr's atomic theory. 2.5.2. Write the position of an element in the periodic system of elements based on the electron configuration of the Bohr atom model.

III.               Learning objectives:

1.       Being aware of the regularity of electron spreading in the atom as proof of the greatness of God YME.

2.       Being able to show curiosity about Bohr's atomic model.

3.       Able to solve the problem of electron spreading in atoms.

4.       Ability to explain the atomic structure of Bohr's atomic model.

5.       Able to know the electron configuration of Bohr's atomic model.

6.       Able to define classes and periods of electron configurations.

7.       Able to write the electron configuration according to Bohr's atomic model.

8.       Be able to write the location of an element in the periodic system of elements based on Bohr's atomic model.

IV.                Material:

1.       Fact:

a.     The atomic constituents.

b.    The periodic system of elements.

2.       Concept:

a.       Atomic number and mass number.

3.       Principle:

a.       Bohr's atomic model

4.       Procedure:

a.       Electron configuration

V. Learning Activities:

A.      Learning strategies:

(1)     Model                    : Guided Inquiry

(2)     Approach              : Scientific

(3)     Method  : Group discussion

B.      Learning Steps:

No.	Type of activity	Time (Minute)
1.	Opening A.      Students pray and greet. B.      Teachers Convey the purpose of learning. C.      Master recalls the atomic structure. D.      Teachers divide groups of students consisting of 4 people / groups. E.       The teacher distributes student worksheets to each student.	10
2	Core activities ·         Observe A.      Students observed the electron configuration of bohr atoms. B.      Students observe the connection of electron configuration to the location of elements in the periodic table. ·         Asking A.      How to determine the spread of electrons in a bohr model atom? B.      How to determine the location of elements in the periodic table ·         Collecting data A.      Students are working on LKS. B.      Shiva was discussing the distribution of electrons in bohr atom atoms and determining the location of elements in the elemental periodic system with members of their respective groups. C.      The teacher observes and records all student activities. D.      Students analyze data obtained from student worksheets. ·         Associating Summing up the rules of electron deployment in atoms and the location of elements in the periodic system of elements according to the bohr atom model. ·         Communicating A.      Students present the analysis results from the student worksheets and present them using the correct language. B.      Students and teachers together conclude the electron configuration rules and the determination of the location of elements in the periodic system of elements according to the bohr atom model.	115
3	Cover A.      Collect student worksheets. B.      Gives the task to practice. C.      Inform future lesson plans.	10

VI.                Instructional Media:

1.       Notebook and LCD Projector

2.       Video

VII.             Learning tools and resources:

1.       Tools              : Student Activity Sheet

2.       Source            : Chemistry Book 1 SMA Class X, Superior Sudarmo, Erlangga, 2013.

VIII.           Assessment of Learning Outcomes:

1.       Attitude Assessment   : Observation

2.       Assessment of knowledge          : Test Write the shape of the description

3.       Skills assessment                         : Performance

Knowing                                                                                                Kerinci, 18 May 2017

Headmaster                                                                                          Subject teachers

Drs. Yusram                                                                                           Nadia Marsila

NIP 196204191993031004                                                                     NIP

APPENDIX:

1.       Assessment of Attitude

No.	Student's name	Cooperation	Discipline	Honesty	Activity

Assessment Guidelines: A = Very Good; B = Good; C = Enough

2.       Knowledge Assessment

No.	Types of Problems	Weight	Total score
1.	Essay	10	50

Value = ((number of scores obtained) / maximum score)) x 4

3.       Skills Assessment

No.	Activities	Good	Medium	Less
1	Reading the class X class book the rules of electron deployment within the atom and the determination of the location of the element in the periodic system of elements according to the bohr atom model.
2	Applying the electron spreading rules within the atom and determining the location of elements in the elemental periodic system according to the bohr atom model in the provided example.
3	Presents electron configuration rules and elemental location determination in the periodic sisitem element according to the bohr atom model.

Value = ((number of v x score) / 9)) x 4

Student worksheet

A.      Title                : Bohr Atomic Structure

B.      Basic Competencies:

1.       Analyzing the atomic structure based on Bohr's atomic theory and the theory of quantum mechanics.

2.       Process and analyze atomic structure based on Bohr atomic theory

C.      Indicators      :

1.       Explain the Bohr atomic theory.

2.       Knowing the electron configuration of Bohr's atomic model.

3.       Determine the classes and periods of the Bohr atomic structure.

4.       Write down electron configurations according to Bohr's atomic theory.

5.       Write the location of an element / atom in the periodic system of elements based on the electron configuration of the Bohr atom model.

D.      Purpose          :

1.       Ability to explain the atomic structure of the Bohr atomic model.

2.       Able to know the electron configuration of Bohr's atomic model.

3.       Be able to determine the class and period of the electron configuration.

E.       Work Steps

Element	No. Atom	Electron configuration					Valence electrons	Group	Period
		K	L	M	N	O
Na	11	2	8	1			1	IA	3
O	8	....					...	...	...
Br	35	...					...	...	...
K	19	...					...	...	...
Ar	...	2	8	8			...	...	...
Rb	37	...					...	...	...

1.       Complete the electron configuration table of the following elements:

F.       Conclusion:

1.       Write in your opinion how the rules of electron configuration according to bohr atom model?

Answer: ....

2.       How to determine the period and class of an element by bohr atomic model?

Answer: ....

WRITTEN TEST WRITTEN

1.       Title                : Bohr Atomic Structure

2.       Basic Competence

A.      Analyzing the atomic structure based on Bohr's atomic theory and the theory of quantum mechanics.

B.      Process and analyze atomic structure based on Bohr atomic theory

3.       Indicators

A.      Explain the Bohr atomic theory.

B.      Knowing the electron configuration of Bohr's atomic model.

C.      Determine the classes and periods of the Bohr atomic structure.

D.      Write down electron configurations according to Bohr's atomic theory.

E.       Write the location of an element / atom in the periodic system of elements based on the electron configuration of the Bohr atom model.

Essay

1.       Explain in your opinion about Bohr's atomic theory?

2.       Describe how the Neils Bohr model of the atom forms?

3.       What is the definition of period and class?

4.       Write down the electron configuration of: 19 X; 10 Y; 35 Z?

5.       Determine the class and period from: 31 A; 7 B; 36 C?

Answer

1.       According to Neils Bohr

A.      The atom consists of a positively charged nucleus and the surrounding circulating electrons are negatively charged.

B.      In atoms, electrons circulate around the nucleus of atoms in a particular orbital known as a stationary motion state (fixed), hereinafter referred to as the primary energy level.

C.      As long as the electron is in the stationary path the energy will be constran, so that no energy is emitted or absorbed.

D.      The electrons can only move from the lower stationary path to the higher path if they absorb energy. Conversely, if an electron moves from a stationary high to a low passage occurs energy liberation.

2.       Bohr's atomic model

3.       The period is the horizontal strip in the periodic table showing the amount of skin filled with electrons.

The class is the vertical lane in the periodic table showing the number of valence electrons.

4.       Electron configuration:

a.       ₁₉ X : 2  8  8  1

b.       ₁₀ Y : 2  8

c.        ₃₅ Z : 2  8  18  7

5.       Period and class:

a.       ₃₁ A : 2  8  18  3            à Group IIIA, period 4

b.       ₇ B   : 2  5                      à Group VA, period 2

c.        ₃₆ C : 2  8  18  8            à Group VIIIA, period 4