Simple Mole Concept Notes

• A mole is defined as the amount of substance which contains equal number of particles (atoms / molecules / ions) as there are atoms in exactly 12.000g of carbon-12.

• One mole of carbon-12 atom has a mass of exactly 12.000 grams and contains 6.02 x 10²³ atoms.

The value 6.02 x 10²³ is known as Avogadro Constant.   

 N_A = 6.02 x 10²³ mol^-1

Example:

Calculate the number H atom in 1 mole of NH3.

Simple Mole Concept of Gases Notes

• Molar volume of any gas at STP = 22.4 dm³ mol^-1

• 1 mole of gas has a volume of 22.4 dm³ at s.t.p.
• At s.t.p, volume of gas (dm³) = number of mole X 22.4 dm³ mol^-1
• 1 mole of gas has a volume of 24.0 dm³ at room temperature.
• At room temperature, volume of gas (dm³) = number of mole X 24.0 dm³ mol^-1

Calculate the number of bromide ions in 2 moles of CaBr2

Acids and Bases Quiz

• Define acid and base according to the Arrhenius concept. Give an example for your answer.
• Define the term conjugate acid-base pair.
• Define amphiprotic species.
• Define an acid and a base according to the Brønsted–Lowry concept. Give an acid–base equation and identify each species as an acid or a base.
• What is meant by the conjugate acid of a base?
• Write an equation in which H₂PO₃ acts as an acid and another in which it acts as a base.
• Define an acid and a base according to the Lewis concept. Give a chemical equation to illustrate.
• Explain why an acid–base reaction favors the weaker acid.
• Give two important factors that determine the strength of an acid. How does an increase in each factor affect the acid strength?
• Define autoionization. Write the expression for Kw. What is its value at 25˚C?
• What is meant by the pH of a solution? Describe two ways of measuring pH.
• Which is more acidic, a solution having a pH of 4 or one having a pH of 5?
• Identify the relationship between the strength of an acid and that of its conjugate base.
• Identify the rules for determining the relative strengths of oxoacids.
• Identify the relative acid strengths of a polyprotic acid and its anions.

Explain the difference between orbit and orbital.

• Orbital refers to the volume in space around the nucleus where the probability of finding a particular electron in ˃ 95%.
• Orbit refers to the fixed circular path around the nucleus where a particular electron revolves.

Explain the difference between relative isotopic mass and relative atomic mass of a particular element.

• Relative isotopic mass is the mass of one atom of a particular isotope of the element. 
• Relative atomic mass is the average mass of all the isotopes present in a sample of naturally occurring element.

When moving across the periodic table from Li to Be to B, the first ionization energy increases from Li to Be, then drops for B. The first ionization energy of B is greater than that of Li. Explain why.

• When moving across a period on the periodic table, the value of the effective nuclear charge increases with atomic number. This causes a general increase from Li to Be to B. 
• The even higher value of Be (greater than B) is due to the increased stability of the electron configuration of Be. 
• Beryllium has a filled s-subshell. Filled subshells have an increased stability, and additional energy is required to pull an electron away. 

What is the uses of iodine?

• A solution containing potassium iodide (KI) and iodine in alcohol is used to disinfect external wounds. Elemental iodine is also used as a disinfectant. 
• Silver iodide is used in photography. 
• Iodine is sometimes added to table salt to prevent thyroid disease. 
• Iodine’s other uses include catalysts, animal feeds and printing inks and dyes. 
• Iodine is used in many household cleaning products available from well-known supermarkets. 
• The health benefits of iodine include the formation of healthy and shiny skin, teeth, and hair. It is an important element for hair care, as lack of this mineral can result in hair loss. Moreover, it also speeds up hair growth and increases follicle strength. 
• Iodine influences the functioning of thyroid glands by assisting in the production of hormones, which are directly responsible for controlling the body’s base metabolic rate.  
• Iodine plays an important role in maintaining optimal energy levels of the body by ensuring the efficient utilization of calories, without allowing them to be deposited as excess fats. 
• A sufficient quantity of iodine in pregnant women is essential to prevent stillbirths or neurocognitive conditions like cretinism in the newborn babies.  

What is the uses of chlorine?

• Chlorine is used for producing safe drinking water and treat swimming pool water. Chlorine kills bacteria – it is a disinfectant.  
• It is also used to make hundreds of consumer products from paper to paints, and from textiles to insecticides. 
•  About 20% of chlorine produced is used to make PVC. This is a very versatile plastic used in window frames, car interiors, electrical wiring insulation, water pipes, blood bags and vinyl flooring. 
•  Another major use for chlorine is in organic chemistry. It is used as an oxidising agent and in substitution reactions.  
• Chlorine is also used for the manufacture of chlorates and it is important in organic chemistry, forming compounds such as chloroform, carbon tetrachloride, polyvinyl chloride, and synthetic rubber. 

What is the uses of fluorine?

• Fluorine is a highly reactive element that is used in processing nuclear fuel, in producing plastics and as a glass etching solution.   
• It can also be found in toothpaste and drinking water, which help prevent dental cavities and it is a component in air conditioning and refrigeration.  
• Because of its highly explosive nature, it is also used in rocket fuels. 
• Fluorine is used to refine uranium, which is used in nuclear reactors. 
• Fluorine is a component of chlorofluorocarbons. Chlorofluorocarbons were used as refrigerants in air conditioning units and freezers until they were banned because of their contribution to ozone depletion. 
• Fluorochemicals, including many high-temperature plastics such as Teflon, are also made using fluorine. 
• Hydrofluoric acid can dissolve glass and is used to etch the glass in light bulbs and in other products. 

What are the important of hydrogen in life?

• The largest use of hydrogen in the world is in ammonia manufacture. 
• The major application of hydrogen is in the catalytic hydrogenation of organic compounds. Unsaturated vegetable and animal oils and fats are hydrogenated to make margarine and vegetable shortening. 
• Hydrogen is used to reduce aldehydes, fatty acids, and esters to the corresponding alcohols. 
• Hydrogen is important because it is involved in the process of enzyme catalysis and because it stabilizes things like nucleic acids and proteins.  
• Hydrogen is important because it offers Earth another fuel source and may free the Earth from using fossil fuels someday.  
• It is currently used as a gas and liquid for many different industries and is often used to provide electricity in the fuel cells of automobiles or in internal combustion engines. For example, NASA used hydrogen to power the space shuttles. 
• Hydrogen has been used as a primary rocket fuel for combustion with oxygen or fluorine and is favoured as a propellant for nuclear-powered rockets and space vehicles. 
• Liquid hydrogen is used in the laboratory to produce low temperatures. 
• Hydrogen is important because it offers Earth another fuel source and may free the Earth from using fossil fuels someday.  

What is the difference Between Molarity and Normality?

Molarity is the number of moles of solute per liter of solution (common measurement of chemical concentration), while normality is the measure of concentration equal to the gram equivalent weight per liter of solution. Normality and molarity are both measures of concentration in chemical solutions. 

For example,  

A 1 M solution of H2SO4 contains 1 mole of H2SO4 per liter of solution. H2SO4 dissociates into H+ and SO4- ions in water. For every mole of H2SO4 that dissociates in solution, 2 moles of H+ and 1 mole of SO4- ions are formed. This is where normality is generally used. 

A 1 M H2SO4 solution will have a normality (N) of 2 N because 2 moles of H+ ions are present per liter of solution. 

N = M*n 

where n is the number of equivalents 

What is the common uses of methane?

• Methane is the main component of natural gas.  It’s a common fabric, plastic, anti-freeze and fertilizer ingredient.  
• Some consumers use the methane in natural gas as a source of energy while cooking. Others use it to heat and cool their homes. 
• Through a process called distributed generation, the methane in natural gas can create electricity.  
• Methane reacts at high temperatures with steam to yield the hydrogen used in the manufacturing of explosives and ammonia-based fertilizers. 
• Chemical reactions with this compound also yield carbon tetrachloride, methanol, chloroform and carbon black. Carbon black is used in the rubber of tires as a reinforcing agent. Chloroform is utilized in applications such as coolant and spot remover. Carbon tetrachloride is the active ingredient in fire extinguishers. 
• Other valuable chemicals derived from methane include methanol, chloroform, carbon tetrachloride, and nitromethane. The incomplete combustion of methane yields carbon black, which is widely used as a reinforcing agent in rubber used for automobile tires. 

What is the uses of argon?

• Argon is widely used as an inert gas to create an oxygen- and nitrogen-free environment for various heat-treating processes.  
• It is used for metal production, welding and metallurgy, lighting and in the automotive industry. 
• Argon is used for filling fluorescent and incandescent light bulbs. Argon does not react with the filament and prevents oxygen from corroding it.  
• In the welding and metal fabrication industry, argon is used to create an inert atmosphere between the surrounding air and liquid metal. The gas also prevents oxidation risks and minimizes smoke emissions. 
• Argon is used in the automotive industry to weld mufflers, frames and other auto parts. It also creates a nitrogen- and oxygen-free environment for the annealing process and is an important component of airbags. The tires of some luxury vehicles contain argon to reduce road noise and protect the rubber.  
• In metal production, argon is used to create a non-reactive blanket during the manufacture of titanium and other reactive elements and as a protective environment for growing germanium and silicon crystals. 

What is the important of ammonia in our life?

• Ammonia is important because it is a vital source of nitrogen to support plant life. It is also used industrially to make dyes, plastic, explosives, drugs, nitric acid and ammonium hydroxide.  
• Diluted ammonium hydroxide is used as a household cleaner. 
• Plants use the nitrogen in ammonia to produce necessary proteins.  
• Urea, ammonium sulfate, ammonium nitrate, ammonium phosphate and pure ammonia are all used as commercial fertilizers for nitrogen-poor soil. Ammonium nitrate is also a component of explosives, ammonium phosphate is used in flame-retardant wood treatments and ammonium sulfate is present in chemicals used to tan leather. 
• Ammonium salts are used in dry-cell batteries, smelling salts and water treatments.  
• Liquid ammonia is used as an industrial refrigerant. Ammonia makes an ideal refrigerant because it can absorb large amounts of heat without its temperature rising. 

What is the uses of copper in our daily lives?

• Copper is commonly used in construction, electrical wiring, plumbing and the manufacture of vehicles. It is also used to make parts for fixtures in homes. 
• Since copper is naturally antimicrobial, it is often used to make objects that are touched frequently, such as faucet handles and doorknobs. It is also highly conductive, so it is used for electrical wiring and in the construction of electronic microchips. It is soft and malleable yet strong, making it an appropriate choice for plumbing and HVAC pipes. It also corrodes very slowly in seawater and resists barnacles, so it is a good material for ship hulls. 
• Copper is mixed with zinc to form brass, and copper is mixed with tin to form bronze. Brass retains most of copper's beneficial qualities but has better acoustic properties, so it is used to make musical instruments. Aluminum bronze is commonly used in vehicle and aircraft parts.