Unit
of Education:
Subject:
Chemistry-Specialization
Class
/ Semester: X / 2
Basic
Material: Concept Mol
Time:
4 × 45 minutes
A. Basic
Competence
1.1
Recognizing the orderliness of the
structure of material particles as a manifestation of the greatness of God
Almighty and the knowledge of the particle structure of matter as the result of
human creative thought that the truth is tentative
2.1
Demonstrate scientific behavior (curiosity, discipline, honest, objective,
open, able to distinguish facts and opinions, resilient, conscientious,
responsible, critical, creative, innovative, democratic, communicative) in
designing and experimenting and discussing embodied In everyday attitude.
2.2
Demonstrate co-operative, courteous, tolerant, peace-loving and caring about
the environment and thrifty in utilizing natural resources.
2.3
Demonstrate responsive, and proactive behavior as a means to solve problems and
make decisions.
3.11
Applying the concept of relative atomic mass and relative molecular mass, reaction
equations, fundamental laws of chemistry, and the concept of moles to solve
chemical calculations
3.11.1
4.11 Processing and analyzing relative atomic mass related data and relative molecular mass, reaction equations, basic chemical laws, and the concept of moles to complete chemical calculations
4.11 Processing and analyzing relative atomic mass related data and relative molecular mass, reaction equations, basic chemical laws, and the concept of moles to complete chemical calculations
B. Indicators of Competency Achievement
1.
Analyze the concept of mol to complete chemical calculations (the relationship
between the number of moles, particles, mass and gas volume)
2.
Discuss empirical formulas and molecular formulas as well as hydrate compounds.
3.
Discuss the determination of the substance content in the mixture
4.
Analyzing the concept of moles for the solution of equations of reactions and
limiting reagents .
.
C.
Learning Objectives
Through group
discussion activities in learning about Mol Concept, students are expected to
be actively involved in learning activities, able to work together and be
responsible in giving opinions, answering questions, giving suggestions and criticism,
and can:
1) Calculates
moles, molar mass and molar gas volume
2) Associate
an empirical formula with molecular formula to calculate the number of water
molecules in a hydrate compound
3) Calculating
the number of substances in the mix (% mass% Volume, bpj, molarity, molality,
and mole fraction)
4) Apply
chemical counts in the reaction equations and limiting reagents
D. Learning Materials
Material Prerequisites:
1.) 1st
Meeting Materials
A. Mol
(origin of the word moles / latin means a number of masses)
The
concept of mole is used to express the amount of substance that reacts. In
general, moles are units of quantities of substances that represent the amount
of particles of very large substances. Where 1 mole is the number of substances
containing the number of particles equal to the number of atoms present in 12
grams of C-12 ie 6.02 x 1023 particles
1)
The relationship of moles to the number of particles
1 mol = 6.02 x 1023 (constant
Avogadro)
2) Mole relations with mass (grams)
Mol = gram / (Ar or Mr)
3)
Mole relationship with
volume
a)
The gas volume at the same temperature
and pressure
(Volume gas I) / (Volume gas II)
= (Mol gas I) / (mol gas II)
b)
The volume of gas in the standard state (STP)
1 mol of gas (STP) = 22.4 Liters
A Compound
Composition
1) Percentage of In Compounds
% A in compound AxBy = (x.Ar A) / (Mr
AxBy) x 100%
% B in the compound AxBy = (y.Ar B) /
(Mr AxBy) x 100%
2) Empirical Formulas and Molecular Formulas
2) Empirical
Formulas and Molecular Formulas
RM = (RE)n
Mr = (∑ArRE)n
The steps determine the empirical
formula.
•
Calculate the ratio of% or grams of the compounding elements of the compound
·
Calculates the mole ratios of these
elements by the way% or grams are divided by Ar of each element.
·
Write the mole composition of the constituent
elements with round and simple numbers
·
Write an empirical formula
Example:
An NxOy oxide contains 30.43% nitrogen
and 69.56% oxygen. If the oxide has Mr = 92, determine the Empirical formula
and the Molecular Formula!
(Ar N = 14 and O = 16).
Answer:
N
= 30,43 % ; O = 69,56 %
Comparison of
moles
Mol
N :
Mol O =
:
= 2,17 : 4,34
= 1
: 2
Empirical oxide
formula is NO2
Mr = ( ∑
Ar RE)n
92 = ( 14 + 2. 16 )n
92 = (46)n
n = 2
The molecular
oxide formula is (NO2) 2 = N2O4
B. Crystal Water
Crystals are solids
that have a regular shape. Some compounds in the form of solid crystals have
the ability to absorb water vapor from the air, so that the crystalline
compound contains crystalline water. Compounds containing crystals are known as
hydrate compounds. The water molecules are densely enclosed in the crystal
arrangement of the compound, so that the hydrate compound remains dry. Crystal
water will be released when heated / dissolved, so that in the process of reaction
of crystal water does not occur chemical reactions.
Example:
• CaSO4. 2H2O shows each unit of crystal
CaSO4 contained 2 water molecules.
• If 38 grams of MgSO4. XH2O was heated,
it was obtained 20 grams MgSO4 (Ar.H = 1, O = 16, Mg = 24 and S = 32).
Determine the price of x!
Answer;
MgSO4 Mass. XH2O = 38 grams
Mass MgSO4 = 20 grams
Mass of H2O = 38 grams - 20 grams = 18
grams
a.
Levels of substances in the mixture
b.
C. Equation of reaction and perection of
barrier
The
molecular form describes the position of the atoms in a molecule, ie the
position of the atoms in the three-dimensional space and the magnitude of the
bonding angles formed in a molecule, as well as the bonds that occur in the
molecule formed by the pairs of electrons. The molecular form can be explained
using various approaches and the easier to use for simple molecules is to use
VSEPR Theory.
According
to VSEPR although the position of electron pairs can be spread among the atoms,
but in general there is a basic pattern of electron pairs due to the force of
repulsion that occurs between the pairs of electrons
In
the molecule the compound generally has an atom that is considered a central
atom. Pairs of electrons located around the central atom can be differentiated
into free electron pairs (p.e.i) and free electron pairs (p.e.b). The free
electron pair has a greater starting force than the bonded electron pair. The
existence of a strong repulsive force in the free electron pair involves a free
electron pair to occupy a wider space than the bonded electron pair. The
electron pairs in a molecule will position themselves, so that the electron
pair's repulsive force is as low as possible, so that the pair of electrons
will be at a distance far from each other.
Accordingly,
the position of the electron pairs has the following archetype and other
patterns:
1)
|
A.
Linear
-
Atoms are arranged in a straight
line
-
Angle of bond towards central atom
180o
-
Example: BeCl2
B. Flat Triangle
-
Atoms in triangular-shaped molecules
arranged in the plane of three atoms will be at the equilateral triangle's
vertex and the center of the triangle is the central atom
-
The angle of bond between the atoms
surrounding the central atom forms an angle of 120 °
-
Example: BCl3
C. Tetrahedron
-
Atoms in a tetrahedron-shaped
molecule will be in a triangular pyramid space with all four areas of
equilateral triangular surface. The central atom is located at the center
of the tetrahedron.
-
angle of bond between atoms located
at all four vertices 109,5o
-
Example: CH4
|
|
|
A.
Linear
-
Atoms are arranged in a straight line
-
Angle of bond towards central atom 180o
-
Example: BeCl2
B.
Flat Triangle
-
Atoms in triangular-shaped molecules
arranged in the plane of three atoms will be at the equilateral triangle's
vertex and the center of the triangle is the central atom
-
The angle of bond between the atoms
surrounding the central atom forms an angle of 120 °
-
Example: BCl3
C. Tetrahedron
-
Atoms in a tetrahedron-shaped molecule will
be in a triangular pyramid space with all four areas of equilateral triangular
surface. The central atom is located at the center of the tetrahedron.
-
angle of bond between atoms located at
all four vertices 109,5o
-
Example: CH4
D. Bipiramida Triangle
-
The central atom is in the
allied plane of two triangular pyramids that coincide, while the circumference
of the surrounding atom will be at the corners of the triangular pyramid formed
-
The angle of bond of each atom
is not the same: axial 90o while equatorial 120o
-
Example: PCl5
E. Octahedron
-
Formed from two rectangular
base quadrangles with their base plates coated, thus forming eight triangular
planes and the central atom located at the center of the rectangular plane of the
two pyramids that coincide
-
90o bond angle
a.
How to Predict
Molecular Forms
A more practical way can be done by
calculating all the valence electrons from the central atom and the electrons
used to form the bonds of the surrounding atoms. The steps are as follows:
Make an electron point formula of the
compound to predict the shape of the molecule
1)
Determine:
a)
The number of valence electrons of a
central atom (a central atom surrounded by two or more other atoms).
b)
The number of electrons coming from the
atoms around the central atom forming the bond.
2)
Add the electrons from step 2a) and 2b)
3)
The number of electron pairs around the
central atom determines the basic shape (pattern shape) of the molecule
4)
The bonded electron pair that determines
the actual shape of the molecule
5)
Pairs of free electrons occupy a wider
space (greater angle)
Example:
·
Molecular shape CH4
Electron
configuration 6C : [He] 2s2 2p2
Valence
electrons C :
4 electrons
Electrons of 4 H
atoms : 4 electrons
The number of electrons around the
central atom (C): 8 electrons
Number of pairs of electrons around the
central atom: 4 pairs.
·
Since C atoms bind 4 H atoms, all
electron pairs are used for bonding. Thus, the bonding electron pair is 4 and
has no free electron pairs. The shape of the molecule is perfectly terahedron
with a bond angle of 109.5o
·
The
shape of NH3 molecules
Electron
configuration 7N : [He] 2s2 2p3
Valence
electrons N :
5 electrons
Elektron
dari 3 atom H :
3 electrons
The number of
electrons around the central atom (N): 8
electrons
Number of pairs of electrons around the
central atom: 4 pairs.
Since N atoms bind 3 H atoms, the
electron pair is used for bonds of 3 pairs and the free electron pair (4-3) = 1
pair. The position of the electron pair in the tetrahedron space, but because
it has a pair of free electrons 1 fruit then the molecular form of pyramid
triangle. More connective angle sempit dari pada tetrahedron sempurna yaitu 107o.
E. Learning Method
1.
Learning Method: Expository, Discussion,
Questionnaire, Guided Discovery
2.
2. Learning Model: A learning approach
is a scientific approach (scientific) Cooperative learning (cooperative
learning) using problem-based learning groups.
F. Media Learning
1.
Stationery,
Worksheet or worksheet (student)
2.
Lap top and LCD
3.
Journal Research
from the internet
G. Learning
Resources
1. Curriculum
syllabus 2013Silabus
Kurikulum 2013
2. Drs.
Unggul Sudarmo, M.Pd.2007, Surakarta: Phibeta
3. Drs.
Michael Purba, M.Sc. 2012, Jakarta: Erland
4. Parning
and Horale, 2004, Jakarta: Yudhisthira.
H. Learning Activities
|
Activities
|
Event Description
|
Time Allocation
|
|
preliminary
|
1.
The teacher gives an opening greeting,
monitoring attendance, order and readiness of students to carry out the
learning.
2.
Students are invited to review and
explain the theory of VSEPR electron
3.
As an apperception to encourage
curiosity and critical thinking, students are invited to observe pictures of
molecular shapes in either archetypal or other forms.
4.
Teachers convey the purpose of learning to be achieved is to study
and explain the theory of electron domains (electron pair) with VSEPR
approach
|
10 minutes
|
|
Core
|
1. Phase
1: Student orientation on the problem
· Teacher asks
student to study and explain theory of VSEPR electron domain.
· By observing
the molecular archetypal images the teacher asks the students to observe the
number of electron pairs of central atoms of a molecule as well as their
relation to the electron-splitting force.
· Teacher asks
students to predict the shape of the molecule either to meet the archetype or
outside the archetype
· If there are
students who have problems, the teacher invites other students to provide
assistance / responses. Where appropriate, teachers provide classical
assistance through the provision of scaffolding.
1. 1.
Phase 2: Organize student learning
· Teacher asks
students to form groups of 4 heterogeneous students (in terms of ability,
gender, culture, or religion) according to the division of groups that have
been planned by teacher.
· Teacher
distributes Student Worksheet (LKS) which contains format to compile problem
review result.
· Teachers go
around looking at working students, looking at and discovering the
difficulties students experience, as well as giving students the opportunity
to ask things that have not been understood.
· Teachers provide
scaffolding for the difficulties students experience individually, group, or
classically.
· Ask students
to work together to collect various sources of information already studied
and think carefully to summarize the results of observations and discussions.
2.
Phase 3: Guiding individual and group assessments..
· Ask students
to look at relationships based on information from related literature
· Teacher asks
student to do analysis with literature provided to conclude observation
result.
3. Phase
4: Develop and present the work
· Teacher asks
students to prepare group discussion reports in a neat, detailed, and
systematic manner.
· Teachers go
around looking at students working on reporting out the results of the
discussion, and providing assistance, if necessary.
· Teacher asks
students to determine group representatives by deliberation to present
(report) report in front of class.
4. Phase 5:
Analyze and evaluate the problem-solving process.
· Teacher asks
all groups to deliberate on a group that presents (communicates) the results
of their discussion in front of the class in a cascading, systematic, polite,
and time-saving manner.
· Teachers give
students opportunities from the presenter group to provide additional
explanations well.
· Teachers
provide opportunities for students from other groups to respond appropriately
to the group discussion group's results.
· Teachers
involve students evaluating group members' answers as well as input from
other students and making arrangements, if the answers are correct.
· Teachers give
opportunities to other groups who have different answers from the first group
of learners to communicate their group discussion results in a cascading,
systematic, courteous, and time-saving manner. If there is more than one
group, then the teacher asks the deliberate students to determine the order
of presentation.
· Next, the
teacher opens the horizon of applying the idea of solving the problem
· • Teachers
encourage students to actively engage in group discussions and help each
other to solve the problem.
· • As long as
the students work in groups, the teacher watches and encourages all students
to engage in the discussion, and directs when there are groups who stray far
away from their work.
· • One
discussion group (not necessarily the best) was asked to present the results
of the discussion to the front of the class. While other groups, responding
and perfecting what was presented.
· • The teacher
asks the class leader to collect all the results of each group's discussion.
|
110 minutes
|
|
Cover
|
1.
Reflection
Students are
asked to conclude about the theory of electron domains and their relationship
of molecular form.
2.
Feedback
Asked in
passing about how the electron's counterpart thrust? How to determine the
molecular shape of a compound?
3.
Assignment
Students are given homework to study
the literature to forecast molecular shapes and relate the relationship of
molecular shapes to the polarity of the compound.
4.
Information
The teacher
ends the learning by giving a message to keep learning and reading the next
material
|
15 minutes
|
I. Assessment
of Learning Outcomes
1. Assessment Technique: attitude observation,
written test
2. Assessment Procedure:
|
No
|
Rated
aspect
|
Assessment
Technique
|
Assessment
Time
|
|
1.
|
Attitude
a.
Engage actively in learning Electron Theory
b.
Cooperate in group activities.
c.
Caring and tolerant of different and creative
problem-solving processes.
|
Observation
|
During learning and during discussion
|
|
2.
|
Pengetahuan Knowledge
a.
Analyzing the theory of the number of elelcrtron
pairs around the atomic nucleus (Electron Domain Theory) to determine the
shape of the molecule
b.
Predict the shape of molecules based on the theory
of the number of electron pairs around the atomic nucleus (Electron Domain
Theory).
|
Written test
|
Completion of
individual and group tasks
|
|
3.
|
Skills
a.
Skillfully apply relevant concepts / principles
and problem solving strategies related to (electron domain theory)
|
Observation
|
Completion of tasks (both individual
and group) and during discussions / presentations
|
Give me please about defenition of lesson plan?
BalasHapusThe lesson plan, or abbreviated RPP, is a teacher's hand in teaching in the classroom. RPP is created by the teacher to assist him in teaching to conform to the Competency Standards and Basic Competencies of the day.
HapusPlease explain about expository and give me the example of this learning method
BalasHapusExpository learning strategy is a learning strategy that emphasizes the process of verbal material delivery from a teacher to a group of students with the intention that students can master the subject matter optimally. In this strategy the subject matter is delivered directly by the teacher. Students are not required to find the material. The subject matter seemed to be ready. Because expository strategies put more emphasis on the process of speaking, it is often called the "chalk and talk" strategy.
HapusThere are several characteristics of expository strategies such as:
Expository strategy is done by delivering verbal subject matter, meaning that spoken orally is the main tool in doing this strategy, therefore often people identify with lectures.
Usually the subject matter that is delivered is a finished subject matter, such as data or facts, certain concepts that must be memorized so as not to require students to re-think.
The main purpose of learning is mastery of the subject matter itself. That is, after the learning process ends students are expected to understand it correctly in a way to re-express the material that has been described.
The expository learning strategy is a form of a teacher centered approach. It is said that, because in this strategy the teacher holds a very dominant role. Through this strategy the teacher delivered the material in a structured learning with the expected subject matter that can be mastered by students well. The main focus of this strategy is the academic ability (academic achievement) of students. Learning method with lectures is a form of expository strategy.
In this system, the teacher presents the material in a well-prepared, systematic, and complete form so that the students learn to listen and digest it regularly and orderlyly. Broadly speaking, the procedure is the stewardship-serving-presentation-evaluation. Ausubel argues that at higher levels of learning, students do not necessarily have to experience themselves. Students will be able and more efficient to obtain as much information as possible in the shortest possible time. The important thing students develop their mastery over the framework of basic concepts or patterns of basic understanding of something so that it can organize data, information, and experiences related to it.
How do you make the students easy to understand the method you give ???
BalasHapusBy doing some ways, below:
HapusPreparation phase
Before doing the learning process, there is an absolute thing that you must do, so that you and students are equally happy while doing the process of teaching and learning in the classroom. In addition to these reasons, students can also absorb all the things you will convey. This is important to do before the learning process begins in the classroom. If you have missed this preparation stage, your students will not get complete information from the material you want to convey. Do not believe? You can prove it yourself.
1. Creating Learning Objectives
2. Giving Know What Benefits Students Can Get
3. Giving Know What Applications Students Can Apply In Real Life
Then the teacher can also do the learning method as follows:
The method used should be able to generate the motives, interests and passion of student learning.
The teaching methods used should ensure the development of student's personality activities.
The method used should be able to provide opportunities for students to realize the work.
The teaching methods used should be able to stimulate students' desire to learn more, explore and innovate (renewal).
The teaching methods used should be able to educate students in their own learning techniques and how to acquire knowledge through personal effort.
The teaching method used should be able to stop the presentation of a verbal character and replace it with experience or real situation and aim.
Teaching methods that are used should be able to instill and develop the values and attitudes that are expected in the habit of good way of working in everyday life.