Dialogue of
teachers and students
In the classroom
Teacher:
Morning all?
All
students: Morning teacher.
Teacher: Today we will learn about acid and bases. Does anyone
know what is acid and what is a base?
Sonya: me miss, acid is a substance (compound) that causes sour taste in various materials. While the base is a compound that generally has a bitter taste.
Teacher: Yes, that's right Ranti. The theory of acid and base that we will learn there are three, the theory according to Arrhenius, Bronsted-Lowry, and Lewis. According to the theory of Arrhenius acid is a substance which if in the water releases hydrogen ions (H +), whereas a base is a compound which in water can produce OH hid hydroxide ions.
Radika: Miss, I want to ask how the solution if acidic / basic compounds can produce H + / OH- ions that are not soluble in water.
Teacher: good question .Not all compounds dissolve in water so acid-base theory is then improved by Bronsted-lowry. Anyone can help me, to pass on the acid base theory according to Bronsted-Lowry, anyone knows?
Ranti: Me miss, according to this book I read, acid according to Bronsted-Lowry is a substance that can give proton (H⁺) to other substance or proton donor. While a base is a substance that receives protons (H⁺) from another substance that is a proton acceptor.
Sonya: me miss, acid is a substance (compound) that causes sour taste in various materials. While the base is a compound that generally has a bitter taste.
Teacher: Yes, that's right Ranti. The theory of acid and base that we will learn there are three, the theory according to Arrhenius, Bronsted-Lowry, and Lewis. According to the theory of Arrhenius acid is a substance which if in the water releases hydrogen ions (H +), whereas a base is a compound which in water can produce OH hid hydroxide ions.
Radika: Miss, I want to ask how the solution if acidic / basic compounds can produce H + / OH- ions that are not soluble in water.
Teacher: good question .Not all compounds dissolve in water so acid-base theory is then improved by Bronsted-lowry. Anyone can help me, to pass on the acid base theory according to Bronsted-Lowry, anyone knows?
Ranti: Me miss, according to this book I read, acid according to Bronsted-Lowry is a substance that can give proton (H⁺) to other substance or proton donor. While a base is a substance that receives protons (H⁺) from another substance that is a proton acceptor.
Teacher: yes, exactly ranti. Well, according to this theory the
acid gives the proton (H⁺) and the
base receives the proton (H⁺). For
example when the solution of HSO4 ˉ is dissolved in CO3²ˉ produces SO4²ˉ and
HCO3ˉ. Therefore, HSO4ˉ is an acid because it gives one proton to CO3²ˉ. and
CO3²ˉ is base because it receives one proton from HSO4ˉ. This is the strength
of the Bronsted-Lowry acid-base theory that can explain any reaction that
occurs in any form, including gases, non-aqueous solutions, aqueous solutions,
and heterogeneous mixtures. Radika: Oh, so there is another theory yes miss. So it can be
concluded that the acid according to Bronsted-Lowry is a proton donor, whereas
a base is a proton acceptor. Thank you miss I already understand it. Teacher: okay if no more questions we continue to the next material that is
the theory of lewis. Lewis states acid is a compound capable of accepting
pairs of electrons from other compounds, or acceptor pairs of electrons, while
bases are compounds that can provide pairs of electrons to other compounds or
electron pair donors. The acid-base concept developed by Lewis is based on
covalent coordination bonds. Still remember ? Coordinate covalent bonding is a
chemical bond formed from the use of a shared electron used by the electron
from one of the bonded atoms or molecules. Atoms or species that provide
electron pairs in forming covalent coordination bonds act as bases, while
atoms, molecules or species that accept electron pairs are referred to as
acids. With this concept can be explained the occurrence of acid-base reaction
that occurs in metal ions with a molecule or ion.
Sonya: miss I want to ask whether the advantages and disadvantages of Lewis acid-base theory compare to others?
Teacher: The merits of Lewis's acid and bases theory:
A. Lewis's acid and base theory is capable of explaining a substance having both basic and acidic properties with other solvents and even with no solvent.
B. Lewis's acid and bases theory is capable of explaining a substance having both alkaline and molecular acids or ions having PEB or free electron pairs. Examples are in the process of formation of complex compounds.
C. Lewis's theory of acids and bases are able to explain and explain an alkaline compound of organic substances, for example in DNA and RNA therein containing N atoms, nitrogen, which has PEB or free electron pairs
Lack of Lewis acid and base theory:
Lewis theory has a weakness that is only able to explain acid-base which has 8 ions or octets.
Sonya: thank you miss for the answer
Sonya: miss I want to ask whether the advantages and disadvantages of Lewis acid-base theory compare to others?
Teacher: The merits of Lewis's acid and bases theory:
A. Lewis's acid and base theory is capable of explaining a substance having both basic and acidic properties with other solvents and even with no solvent.
B. Lewis's acid and bases theory is capable of explaining a substance having both alkaline and molecular acids or ions having PEB or free electron pairs. Examples are in the process of formation of complex compounds.
C. Lewis's theory of acids and bases are able to explain and explain an alkaline compound of organic substances, for example in DNA and RNA therein containing N atoms, nitrogen, which has PEB or free electron pairs
Lack of Lewis acid and base theory:
Lewis theory has a weakness that is only able to explain acid-base which has 8 ions or octets.
Sonya: thank you miss for the answer
The break bell rang
Teacher:
well all the material I can deliver. Hopefully can be understood and learn
again at home yes. Good afternoon.
All the
students: good afternoon miss.
https://www.youtube.com/watch?v=b1Ga-7YCJWA
Please you explain ,why acid or base use indicator to measure it ?
BalasHapusThat artificial indicators have an advantage in determining the pH range of an acid or base solution under test. That is, in addition to providing color change, artificial indicators can also measure the pH value of a test solution. This can be done when the pH of the tested solution falls within the pH range of the indicator used.
HapusTo recall some artificial indicators.
What is the difference between acid and base specific?
BalasHapus1. Differences Flavor
HapusThe most striking difference between acids and bases lies in the taste of both. Sour acids, as the name implies must have a sour taste if tasted with the tongue. A simple example is vitamin C which contains ascorbate compounds, when you suck this substance, you will definitely feel a strong sour taste. While alkaline substances generally have a bitter taste. If you do not believe it, put a little bath soap into your tongue. The unbearable bitterness will surely be instantly felt.
2. Lakmus Paper
Litmus paper is the most commonly used acid indicator. Litmus paper itself there are 2 types, namely red litmus paper and blue litmus paper. Compounds or acidic substances will generally be able to redden the blue litmus paper and not change the color of red litmus paper. While the compound or alkaline substances will generally be able to brighten red litmus paper and do not change the color of blue litmus paper.
3. Differences of Nature
Differences of acids and bases can also be seen from its nature. The nature of the acid is corrosive or can erode other objects (especially metals) that come into contact with it. While the basic properties are caustic or can damage the skin. Both the properties of acids and bases you must understand if you are in the laboratory. These properties are very dangerous if you do not pay attention to health and safety.
What do you think of the advantages and disadvantages of scientific learning methods for students
BalasHapuslecture
Hapusadvantages
1) Teachers easily master the class
2) Easy to implement
3) Can follow students in large numbers
4) The teacher is easy to explain
deficiency
1) Activity teaching becomes verbalism (meaning of words)
2) Students who are more responsive from the visual side will be a loss and learners more responsive auditifnya can be greater receive it
3) If it's too long
4) difficult to control access to learning achievement of students
5) Causing a passive child
According to Arrhenius theory, an acid is defined as a compound which, if dissociated in aqueous solution liberates H +, would it dissociate only in aqueous solution?
BalasHapusNot all compounds dissolve in water so the acid-base theory is then fixed by Bronsted-lowry.
HapusAccording to Bronsted-Lowry acid is a compound that can contribute protons, ie H + ions to other compounds / substances. Bases are compounds that can receive protons, ie H + ions from other compounds.
Why is the 2013 curriculum using a scientific approach?
BalasHapusBecause the scientific approach (scientific appoach) in the learning process involves digging information through observation, asking, experimenting, then processing data or information, presenting data or information, followed by analyzing, reasoning, then concluding, and creating. For certain subjects, materials, or situations, it is very likely that this scientific approach is not always aptly applied procedurally. Under these conditions, the learning process must, of course, still apply scientific values or traits and avoid non-scientific values or traits.
HapusWhat can be done to determine the pH of a compound or substance?
BalasHapusThe degree of acidity or Potenz Hydrogen (pH) of a solution can be determined using the universal indicator and pH meter.
HapusUniversal 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.
1) 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.
2) Indicator Solution
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. Another example of liquid indicators is the phenolphthaline indicator (Phenolphtalein = pp). PH below 8, phenolphthaline is colorless, and will be red wine if the pH of the solution is above 10 (Fig.
Potenz Hydrogen (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.