JEE MAIN 2020 NEWS
NATIONAL LEVEL ONLINE TEST
Surface Chemistry holds a weightage of 17.9% in JEE Main Chemistry Syllabus. Topics tested from surface chemistry in JEE Main are Thermodynamics of Adsorption, Emulsions and Colloids. Minimum of 1 question is asked from this section. The aspect combined with Chemical Kinetics holds a lot of weightage in JEE Advanced paper as well with at least 8 questions. Check JEE Main Chemistry Preparation Tips
JEE Main 2020 January session had one question on surface chemistry in each shift so was the case in 2019. Before proceeding for the study notes, lets take a quick look in one of the questions asked in 2019:
Aerosol is a kind of colloid in which:
Solid is dispersed in gas
Gas is dispersed in solid
Gas is dispersed in liquid
Liquid is dispersed in water
Unable to solve the question, read further to get acquainted with surface chemistry aspects.
Surface chemistry is defined as the detailed study of surfaces and interfaces.
There are two types of phenomena that can be commonly seen in this topic which is
ADSORPTION and ABSORPTION; let's take a look upon both of the phenomena
ADSORPTION: When any substance stays on the surface of the substance then it is known as adsorption. The species which is going to adsorb is known as adsorbent and the surface onto which it takes place is known as the adsorbate. For example, silica gels, clays are the most commonly seen substance that possess adsorption qualities.
There is a process known as desorption also which is known as the removal of the adsorbed substance from the surface of an element.
ABSORPTION: When the substance fully penetrates inside the surface is known as absorption. The most common example of it is soaking cloth in the water. The water then penetrates into the cloth piece and we can say that the absorption process is occurring there.
An example of solid sol is?
|Substance penetrate fully||The substance remains onto the surface only.|
|It is an endothermic process||It is the exothermic process|
|It occurs at a uniform rate||The rate goes from increasing to decreasing|
|It is unaffected by the temperature||It is affected by the temperature|
Practice with JEE Main Question Paper
There are mainly two types of adsorption are there namely physisorption and chemisorption.
It involves adsorption of gases on the solid surface via weak van der Waal’s forces.
Characteristics: There is no specificity in case of physical adsorption.
When the gas molecules or atoms are held to the solid surface via chemical bonds, this type of adsorption is chemical adsorption or chemisorption.
Characteristics of Chemical Adsorption:
Haemoglobin and gold sol are examples of:
It is the graphical representation of the amount of adsorbent adsorb on the surface/adsorbate in relation to the pressure and constant temperature.
x/m= k. p1/ n
where (n > 1)
x is the mass of the gas adsorbed, m is the mass of the adsorbent, p is the pressure, k and n are constants which depends on the nature of the adsorbent and the gas at a particular temperature. Taking the log of the above equation, the following equation will be observed
log x/m = log k +1/n log p
Then the graphical representation made accordingly to the equation mentioned above.
It is the process occur when the potassium chlorate decomposes into the potassium chloride and oxygen at the temperature of about 650-870K, but by adding magnesium dioxide the rate of reaction becomes faster and no need of high temperature is required there then it is known as the catalysis process occur there. This process is generally useful by fastening up the chemical reaction and in the short duration of the time.
Important features of the catalysis process:
These are known as a biochemical catalyst which is complex and organic in nature and are obtained from plants and animals. For example Invertase; it converts sucrose into fructose and glucose.
Characteristics of enzyme catalyst:
This is known as the heterogeneous system in which one substance is dispersed due to the very fine nature of it, it can mix well in the dispersion medium. This process has two kinds of activities going on known as;
Properties of the colloidal solution:
Among colloids cheese, milk and smoke, the correct combination of the dispersed phase and dispersion medium is:
Two liquids colloidal systems form an emulsion. These are of two types:
Hence, these above-mentioned notes will give the basic idea about the surface chemistry topic and helps a student preparing for IIT exam to strengthen his/her base.
Chemistry is a mixed subject, which means it contains both theoretical and practical based problems. Thus in order to achieve good marks, a student needs to practice upon both the skills. Students must take a look at some points before preparing for the exam which are:
|Week 1 (June 16 to 22)||Physical Chemistry bears the most weightage in JEE Main Chemistry. High-weightage chapters from this area such as Electrochemistry, Atomic Structure, and Equilibrium to be studied in the beginning. Then, study less important chapters like Surface Chemistry and Solid State. Pick two chapters each day and study all the essential concepts and reactions.|
|Week 2 (June 23 to June 30, 2020)||Study Organic Chemistry during this week. Allocate more time to chapters with high weightage such as Aromatic Compounds, Alcohol, Alkyl Halides, and Ether. Then, study chapters with lower weightage such as Biomolecules and Carbonyl Compounds.|
|Week 3 (July 1 to 4, 2020)||Study Inorganic Chemistry for this week. Start by studying chapters with the highest weightage like p Block, s Block, and Chemical Bonding. Move on to study less important chapters such as Metallurgy and Qualitative Analysis.|
|Week 4 (July 5 to July 10, 2020)||Brush through your study notes, important concepts, and reactions. Answer previous year’s papers for enhanced practice. Pick out questions from the Chemistry section and attempt them as quickly as you can, preferably within 45 minutes to 1 hour.|
|Week 5 (July 10 to 17, 2020)||Attempt mock tests every day of this week. Revise important concepts and reactions from all the chapters.|
|JEE Main Exam Week (July 18 to 23, 2020)||Read the analysis of ongoing JEE Main papers and compare your performance. Use JEE Main Rank Predictor to estimate your rank and desired college.|