Chemistry 5 Revision Flashcards
Acid hydrolysis of nitriles
Heated under reflux with dilute acid, produce carboxylic acid and salt
Hypochlorous acid (HOCl) can indeed decompose in the presence of sunlight,
Hypochlorous acid (HOCl) can indeed decompose in the presence of sunlight, particularly when exposed to ultraviolet (UV) radiation. The decomposition of HOCl can result in the formation of other compounds, such as oxygen (O2) and hydrogen chloride (HCl). This process is often accelerated in the presence of certain catalysts or under specific environmental conditions. The decomposition of HOCl plays a role in various chemical and biological processes, including water treatment, disinfection, and atmospheric chemistry.
Oil drop experiment
The “oil drop experiment” is attributed to American physicist Robert A. Millikan, not “Milkman.” This experiment was conducted in 1909 and was designed to determine the fundamental unit of electric charge, known as the electron charge ().
In the oil drop experiment, Millikan observed the motion of tiny oil droplets suspended in a chamber filled with air. By applying an electric field to the chamber, Millikan was able to manipulate the motion of the oil droplets. By carefully measuring the electric field strength required to balance the gravitational force acting on the droplets, Millikan was able to determine the magnitude of the electric charge on each droplet.
Through meticulous experimentation and analysis, Millikan determined that the electric charge on each droplet was a multiple of a fundamental unit of charge, which we now know as the electron charge (). He measured the charge on multiple droplets and found that the charges were all integer multiples of a certain value, which he determined to be approximately coulombs, the charge of a single electron.
Therefore, the oil drop experiment provided strong experimental evidence for the quantization of electric charge and enabled Millikan to determine the value of the electron charge with remarkable precision.
Change in heat is less than zero
Exothermic
In industrial production of hydrogen from natural gas, CO2 produced is collected by
Washing under pressure
Potassium dichromate (( \text{K}_2\text{Cr}_2\text{O}_7 )) is commonly used as an oxidizing agent in various chemical reactions
and is often used as an indicator in titrations. It is orange-red in color.When certain gases are introduced into a solution of potassium dichromate, they can undergo redox reactions with the dichromate ion (( \text{Cr}_2\text{O}_7^{2-} )), causing it to change color. Some gases that can cause such color changes include:Sulfur dioxide (SO2): Sulfur dioxide can reduce potassium dichromate to chromium(III) ions (( \text{Cr}^{3+} )), causing the orange-red color of potassium dichromate to change to green as chromium(III) ions are green in solution.Hydrogen sulfide (H2S): Hydrogen sulfide can also reduce potassium dichromate to chromium(III) ions, resulting in the same green color change.Carbon monoxide (CO): Carbon monoxide can reduce potassium dichromate to chromium(III) ions as well, causing the solution to change to a green color.These are just a few examples of gases that can change the color of potassium dichromate solution. The specific color change observed will depend on the concentration of the potassium dichromate solution, the concentration of the gas, and the reaction conditions.
Limestone (calcium carbonate, CaCO3) is commonly used in the extraction of iron from a blast furnace primarily for two purposes:
Limestone (calcium carbonate, CaCO3) is commonly used in the extraction of iron from a blast furnace primarily for two purposes:Fluxing Agent: Limestone is added to the blast furnace as a fluxing agent. In the high-temperature environment of the blast furnace, limestone decomposes to form calcium oxide (CaO) and carbon dioxide (CO2). The calcium oxide reacts with impurities in the iron ore, such as silica (SiO2), to form a slag, which is a molten mixture of calcium silicate (CaSiO3) and other impurities. The slag floats on top of the molten iron and is easily separated, allowing impurities to be removed from the iron.[ \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 ]Control of Sulfur Content: Limestone also helps control the sulfur content in the blast furnace. When limestone decomposes, some sulfur impurities in the iron ore combine with the calcium oxide to form calcium sulfide (CaS). This calcium sulfide is then removed as part of the slag, helping to reduce the sulfur content in the iron produced.[ \text{CaO} + \text{FeS} \rightarrow \text{CaS} + \text{FeO} ]Overall, the addition of limestone to the blast furnace helps improve the efficiency of the iron extraction process by facilitating the removal of impurities and controlling the sulfur content in the final iron product.
Aromatics and aliphatic compounds can be distinguished using bromine in different reaction conditions:
Aromatics and aliphatic compounds can be distinguished using bromine in different reaction conditions:
1. Bromine Test for Alkenes (Unsaturated Compounds): • Aliphatic compounds containing carbon-carbon double bonds (alkenes) readily react with bromine () in an addition reaction. The reddish-brown color of bromine disappears as it adds across the double bond, forming a colorless compound. This reaction is rapid and does not require the presence of light or heat. • Aromatics, on the other hand, do not readily react with bromine under normal conditions because the benzene ring is stable and does not undergo addition reactions with bromine. 2. Bromine Test for Alkanes (Saturated Compounds): • In the presence of ultraviolet (UV) light or heat, alkanes (both aliphatic and aromatic) can react with bromine () in a substitution reaction. The color of bromine fades as it substitutes one of the hydrogen atoms in the alkane, forming a bromoalkane. • However, alkanes react more slowly with bromine compared to alkenes, and the reaction requires the presence of UV light or heat to proceed. This reaction is not commonly used as a test to distinguish between aromatics and aliphatics due to its slower rate and the need for specific reaction conditions.
In summary, the bromine test for unsaturated compounds (alkenes) is more commonly used to distinguish between aromatics and aliphatics, as alkenes readily react with bromine under normal conditions to form colorless compounds, while aromatics do not undergo addition reactions with bromine.
Sure, here are examples of primary, secondary, and tertiary amines along with their differences:
- Primary Amine:
• Example: Ethylamine ()
• Structure: In ethylamine, the nitrogen atom () is directly bonded to one hydrogen atom () and one ethyl group ().
• Characteristics: Primary amines have one alkyl or aryl group attached to the nitrogen atom. They can undergo substitution reactions to form secondary and tertiary amines.- Secondary Amine:
• Example: Dimethylamine ()
• Structure: In dimethylamine, the nitrogen atom is directly bonded to two methyl groups ().
• Characteristics: Secondary amines have two alkyl or aryl groups attached to the nitrogen atom. They can undergo substitution reactions to form tertiary amines. - Tertiary Amine:
• Example: Trimethylamine ()
• Structure: In trimethylamine, the nitrogen atom is directly bonded to three methyl groups ().
• Characteristics: Tertiary amines have three alkyl or aryl groups attached to the nitrogen atom. They cannot undergo further substitution reactions at the nitrogen atom due to the absence of hydrogen atoms.
- Secondary Amine:
Differences:
• The main difference between primary, secondary, and tertiary amines lies in the number of alkyl or aryl groups attached to the nitrogen atom. • Primary amines have one, secondary amines have two, and tertiary amines have three alkyl or aryl groups attached to the nitrogen atom. • This structural difference affects their reactivity in chemical reactions. For example, primary amines can be further substituted to form secondary and tertiary amines, while tertiary amines cannot undergo further substitution reactions at the nitrogen atom.
Sure, here are examples of primary, secondary, and tertiary amines along with their differences:
- Primary Amine:
• Example: Ethylamine ()
• Structure: In ethylamine, the nitrogen atom () is directly bonded to one hydrogen atom () and one ethyl group ().
• Characteristics: Primary amines have one alkyl or aryl group attached to the nitrogen atom. They can undergo substitution reactions to form secondary and tertiary amines.- Secondary Amine:
• Example: Dimethylamine ()
• Structure: In dimethylamine, the nitrogen atom is directly bonded to two methyl groups ().
• Characteristics: Secondary amines have two alkyl or aryl groups attached to the nitrogen atom. They can undergo substitution reactions to form tertiary amines. - Tertiary Amine:
• Example: Trimethylamine ()
• Structure: In trimethylamine, the nitrogen atom is directly bonded to three methyl groups ().
• Characteristics: Tertiary amines have three alkyl or aryl groups attached to the nitrogen atom. They cannot undergo further substitution reactions at the nitrogen atom due to the absence of hydrogen atoms.
- Secondary Amine:
Differences:
• The main difference between primary, secondary, and tertiary amines lies in the number of alkyl or aryl groups attached to the nitrogen atom. • Primary amines have one, secondary amines have two, and tertiary amines have three alkyl or aryl groups attached to the nitrogen atom. • This structural difference affects their reactivity in chemical reactions. For example, primary amines can be further substituted to form secondary and tertiary amines, while tertiary amines cannot undergo further substitution reactions at the nitrogen atom.
The relatively high boiling points of alcohols are primarily due to the presence of hydrogen bonding between alcohol molecules.
The relatively high boiling points of alcohols are primarily due to the presence of hydrogen bonding between alcohol molecules. Hydrogen bonding occurs when a hydrogen atom attached to a highly electronegative atom (such as oxygen or nitrogen) interacts with another electronegative atom in a neighboring molecule.
In the case of alcohols, the hydrogen atom attached to the oxygen atom in one alcohol molecule can form a hydrogen bond with the lone pair of electrons on the oxygen atom of another alcohol molecule. This intermolecular hydrogen bonding leads to stronger attractive forces between alcohol molecules, requiring more energy to overcome and thus resulting in higher boiling points compared to hydrocarbons of similar molecular weights.
Additionally, the longer the carbon chain in the alcohol molecule, the greater the surface area available for intermolecular interactions, further increasing the strength of the intermolecular forces and contributing to higher boiling points.
In summary, the relatively high boiling points of alcohols compared to hydrocarbons of similar molecular weights are primarily attributed to the presence of hydrogen bonding between alcohol molecules.
When an alkyne reacts with hydrogen iodide (HI), it undergoes an addition reaction known as hydrohalogenation to form an alkyl iodide.
When an alkyne reacts with hydrogen iodide (HI), it undergoes an addition reaction known as hydrohalogenation to form an alkyl iodide. The final product depends on the structure of the alkyne.
1. Terminal Alkyne (Acetylene):
• Terminal alkynes react with hydrogen iodide to form vinyl iodides.
• For example, acetylene (CH2) reacts with hydrogen iodide to form vinyl iodide
(CH, = CHI).
2. Internal Alkyne:
• Internal alkynes react with hydrogen iodide to form geminal diiodides (1,2-diiodoalkanes).
• For example, 2-butyne (C4#6) reacts with hydrogen iodide to form 2,2-diiodobutane (CHI2).
The general reaction mechanism involves the addition of hydrogen iodide across the triple bond of the alkyne, resulting in the formation of an alkene intermediate, which subsequently reacts with another molecule of hydrogen iodide to form the final product.
The reaction can be summarized as follows:
Alkyne + HI → Alkyl iodide
It’s important to note that the addition of hydrogen iodide to alkynes follows Markovnikov’s rule, where the iodine atom adds to the carbon atom of the triple bond with the greatest number of hydrogen atoms
n-Heptane
n-Heptane is a paraffin hydrocarbon that is particularly prone to causing knocking in internal combustion engines.
n-Heptane is a straight-chain alkane hydrocarbon with seven carbon atoms (C7H16). It is a major component of gasoline and is often used as a reference standard for the octane rating scale. However, despite its importance in gasoline, n-heptane has a relatively low octane rating and is highly prone to causing knocking when used as a fuel in internal combustion engines.
Because of its tendency to cause knocking, n-heptane is typically not used as the sole component of gasoline. Instead, gasoline blends contain various additives and other hydrocarbons with higher octane ratings to improve engine performance and reduce the risk of knocking.
Thank you for bringing up n-heptane as an example of an undesirable paraffin hydrocarbon prone to knocking.⬤
Steel
Chromium and nickel improve quality of steel
Coal gas
Coal gas, also known as coal-derived gas, is a gaseous mixture produced by the destructive distillation of coal. The composition of coal gas can vary depending on factors such as the type of coal used, the temperature of the distillation process, and the specific production methods employed. However, typical components of coal gas include:
1. Hydrogen (H2): Hydrogen is one of the primary components of coal gas and is typically present in significant amounts. It is often the main combustible component and contributes to the heating value of coal gas. 2. Methane (CH4): Methane, the main component of natural gas, is also present in coal gas. It is a valuable fuel and contributes to the energy content of the gas. 3. Carbon Monoxide (CO): Carbon monoxide is produced during the incomplete combustion of coal and is a common component of coal gas. It is a toxic gas but can be used as a fuel in certain applications. 4. Carbon Dioxide (CO2): Carbon dioxide is formed as a byproduct of combustion reactions and is present in coal gas, albeit in smaller quantities compared to carbon monoxide. 5. Hydrocarbons: Coal gas may contain various hydrocarbons such as ethylene, propylene, and other alkanes and alkenes produced during the distillation process. 6. Tar and Other Impurities: Coal gas may also contain tar, sulfur compounds, ammonia, and other impurities depending on the source and production process.
It’s important to note that coal gas is not commonly used today due to its high levels of pollutants and the availability of cleaner and more efficient energy sources such as natural gas and electricity. However, coal gas historically played a significant role in providing lighting, heating, and cooking fuel before the widespread adoption of cleaner alternatives.
K L M N
2 8 18 32
Coffee stain
Solution of borax in water
Acid used to remove rust
Tetraoxosulphate (vi)
CaSo4
Slightly soluble in water
The IUPAC name for ( \text{LiAlH}_4 ) is Lithium aluminium hydride.
The IUPAC name for ( \text{LiAlH}_4 ) is Lithium aluminium hydride.Here’s the breakdown:”Lithium” represents the cation (Li⁺), which is a metal in this compound.”Aluminium” represents the central atom (Al), which is bonded to hydrogen.”Hydride” indicates that hydrogen (H⁻) is present in the compound.So, the compound is named as “Lithium aluminium hydride.”
Tartaric acid
Component of baking powder
Calcium oxide heated with carbon
Converted to carbide
Cathode rays
Certainly, here are some key points about cathode rays:
1. Discovery: Cathode rays were discovered by Sir William Crookes in 1879. He observed that when a high voltage was applied across electrodes in a vacuum tube, a fluorescent glow appeared on the glass wall near the cathode (negative electrode). 2. Nature: Cathode rays are streams of electrons emitted from the cathode (negative electrode) in a vacuum tube when a high voltage is applied across the electrodes. They travel in straight lines and can cast shadows, indicating their particle-like nature. 3. Properties: • Cathode rays are negatively charged particles, later identified as electrons. • They have a very small mass compared to atoms. • They travel at high speeds, typically a significant fraction of the speed of light. • They can be deflected by electric and magnetic fields, indicating their charge and the particle nature. 4. Role in Discoveries: • The discovery of cathode rays played a crucial role in the development of atomic theory and the understanding of electricity and magnetism. • J.J. Thomson’s experiments with cathode rays led to the identification of electrons as fundamental particles present in atoms, and his discovery of the electron’s charge-to-mass ratio helped lay the groundwork for the development of the atomic model. 5. Applications: • Cathode ray tubes (CRTs) were widely used in old television sets, computer monitors, and oscilloscopes. In CRTs, a beam of electrons is used to produce images on a fluorescent screen. • Cathode rays are also used in electron microscopy, where they are focused to produce highly detailed images of microscopic objects.
Overall, the study of cathode rays has significantly contributed to our understanding of the fundamental nature of matter and has led to the development of various technologies with important practical applications.
Negatively Charged: cathode ray
Negatively Charged:
• Experiment: Thomson’s Cathode Ray Tube Experiment
• Setup: A cathode ray tube (CRT) is used, consisting of a vacuum tube with electrodes connected to a high voltage source. The cathode (negative electrode) emits cathode rays, which pass through the tube towards the anode (positive electrode).
• Observation: When a magnetic field is applied perpendicular to the path of the cathode rays, they are deflected towards the positively charged plate, indicating that they are negatively charged particles.
Has Mass: cathode ray
• Experiment: Thomson’s Measurement of e/m Experiment
• Setup: Using the same cathode ray tube setup as before, Thomson applied both electric and magnetic fields perpendicular to each other and to the direction of the cathode rays.
• Observation: By measuring the extent of deflection caused by the electric and magnetic fields and knowing the strength of the fields, Thomson was able to determine the charge-to-mass ratio (e/m) of the cathode rays. This experiment showed that cathode rays have mass, as they are deflected by both electric and magnetic fields.
Travelling in Straight Lines: cathode ray
Travelling in Straight Lines:
• Experiment: Crookes’ Maltese Cross Experiment
• Setup: A cathode ray tube with a Maltese cross-shaped object placed between the cathode and the anode.
• Observation: When the cathode rays pass through the tube, they cast sharp shadows of the Maltese cross on the fluorescent screen placed at the end of the tube. This indicates that the cathode rays travel in straight lines and are not easily deviated from their path.
Quantum numbers
The principal quantum number ((n)), azimuthal quantum number ((l)), magnetic quantum number ((m_l)), and spin quantum number ((m_s)) are quantum numbers used to describe the characteristics of an electron in an atom. Here’s a brief explanation of each:Principal Quantum Number ((n)):Represents the energy level or shell of an electron in an atom.Determines the size and energy of an orbital.The value of (n) can be any positive integer (1, 2, 3, …).Azimuthal Quantum Number ((l)):Also known as the orbital angular momentum quantum number.Specifies the shape of an orbital.The value of (l) depends on the value of (n) and ranges from 0 to (n - 1).For (n = 1), (l) can only be 0 (s orbital). For (n = 2), (l) can be 0 or 1 (s or p orbitals), and so on.Magnetic Quantum Number ((m_l)):Describes the orientation of an orbital in space.The value of (m_l) depends on the value of (l) and ranges from (-l) to (l).For example, if (l = 1) (p orbital), (m_l) can be -1, 0, or 1, representing the three possible orientations of the p orbital along the x, y, and z axes.Spin Quantum Number ((m_s)):Describes the intrinsic angular momentum or spin of an electron.An electron can have one of two possible spin states: spin-up ((m_s = +\frac{1}{2})) or spin-down ((m_s = -\frac{1}{2})).The spin quantum number distinguishes between these two states.These quantum numbers are used to describe the quantum mechanical behavior of electrons in atoms and are crucial for understanding the electronic structure and properties of elements. They provide a framework for predicting the arrangement of electrons in atomic orbitals and determining the chemical behavior of atoms.
