Applied Chemistry CHB-101 Quiz

Disodium salt of EDTA is more soluble in water than EDTA. This enhances its effectiveness in water hardness determination.

<p>Scale is a hard, mineral deposit that forms on the surfaces of boilers, pipes, and other equipment. Sludge is a soft, accumulated sediment that accumulates in boilers. Both can be caused by the presence of dissolved salts in the water, such as calcium and magnesium, as well as silica. Scale and sludge formation hinder heat transfer, leading to energy loss and reduced efficiency. These buildups can also restrict flow, increase pressure, and ultimately result in corrosion and damage to the system.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>The Nernst equation is expressed as: $E = E° - \frac{RT}{nF} lnQ$ , where E is the cell potential under non-standard conditions, E° is the standard cell potential, R is the ideal gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred in the balanced reaction, F is Faraday's constant, and Q is the reaction quotient.</p> Signup and view all the answers

<p>An electrochemical cell converts chemical energy into electrical energy. It consists of two electrodes: an anode and a cathode, immersed in an electrolyte solution. At the anode, oxidation occurs, releasing electrons. These electrons flow through an external circuit to the cathode, where reduction takes place. The electrolyte acts as a medium for ion movement, maintaining electrical neutrality.</p> Signup and view all the answers

<p>Using the Nernst equation: $E = E° - \frac{RT}{nF} lnQ$, we have $E = 1.103 - \frac{8.314 * 298}{2 * 96485} ln(\frac{0.001}{0.1})$. Solving for E gives us E = 1.148 V.</p> Signup and view all the answers

<p>A lithium-ion battery consists of an anode, typically made of graphite, a cathode of lithium metal oxide, and an electrolyte solution containing lithium ions. During discharge, lithium ions from the anode move through the electrolyte to the cathode. During charging, the process is reversed. The battery's efficiency is determined by the rate of electron transfer between the anode and cathode.</p> Signup and view all the answers

<p>Redox</p> Signup and view all the answers

<p>Volume of metal oxide to volume of metal</p> Signup and view all the answers

<p>Aluminum forms a protective oxide layer on its surface that prevents further corrosion. Iron's oxide layer is porous and does not offer the same level of protection, leading to rapid corrosion.</p> Signup and view all the answers

<p>Alloys are mixtures of two or more metals or metals with non-metals. They are often formulated to enhance specific properties, such as strength, hardness, or corrosion resistance. Examples include brass (copper and zinc), bronze (copper and tin), and stainless steel (iron, chromium, and nickel).</p> Signup and view all the answers

<p>Sugar</p> Signup and view all the answers

<p>10^6 m</p> Signup and view all the answers

<p>Optical fibers are thin strands of glass or plastic that transmit light signals over long distances. They rely on the principle of total internal reflection to guide light pulses. Optical fibers are widely used in telecommunications, high-speed internet connections, medical imaging, and industrial sensing.</p> Signup and view all the answers

<p>Nanoparticles are extremely small particles, typically measured in nanometers (10^-9 m). They exhibit unique properties compared to bulk materials. Nanoparticle synthesis methods involve controlled chemical reactions, physical methods like milling and sputtering, or biological approaches using microorganisms.</p> Signup and view all the answers

<p>Photovoltaic materials convert light energy into electrical energy. Dye-sensitized solar cells (DSSCs) utilize a semiconductor material like titanium dioxide coated with a dye. The dye absorbs sunlight and releases electrons, which are transported through the semiconductor to an electrode. The electrons flow through an external circuit and are ultimately collected by an electrolyte solution. This process generates electrical current. DSSCs offer advantages like low manufacturing cost and high efficiency under diffuse light conditions.</p> Signup and view all the answers

<p>200 to 800nm</p> Signup and view all the answers

<p>Chromatography</p> Signup and view all the answers

<p>pH is a measure of acidity or alkalinity of a solution. It is defined as the negative logarithm of the hydrogen ion concentration: $pH = -log[H+]$. For a 0.01 M solution of NaOH, the pOH is -log(0.01) = 2. Therefore, pH = 14 - pOH = 12.</p> Signup and view all the answers

<p>Beer-Lambert's law states that the absorbance of a solution is directly proportional to the concentration of the analyte and the path length of the light beam through the solution. Mathematically, it is expressed as: $A = εbc$, where A is absorbance, ε is the molar absorptivity, b is the path length, and c is the analyte concentration.</p> Signup and view all the answers

<p>Chromatography is a separation technique used to isolate and identify different components of a mixture. It involves distributing the components of a sample between a stationary phase (a solid or liquid) and a mobile phase (a liquid or gas). Based on their different affinities for the two phases, the components separate as they travel through the system. Chromatography can be classified based on the stationary and mobile phases used.</p> Signup and view all the answers

<p>Conductometry measures the electrical conductivity of a solution, which is directly proportional to the concentration of ions present. The instrument typically consists of two electrodes immersed in the solution, and the resistance between these electrodes is measured. Conductometry finds applications in determining the ionic strength of solutions, monitoring reactions involving ion production or consumption, and analyzing water quality.</p> Signup and view all the answers

<p>(i) IR spectroscopy is a powerful analytical technique that identifies and analyzes molecules based on their vibrations and rotations. It utilizes infrared radiation to probe the molecule, and specific frequencies of absorption or transmission can be correlated to the presence of particular bonds and functional groups. (ii) Instrumental techniques are essential for modern scientific research and analysis. They provide precise measurements, increased sensitivity, automation, and objectivity, allowing for more accurate and reliable data collection and interpretation. Instrumental techniques have revolutionized fields like chemistry, biology, materials science, and medicine.</p> Signup and view all the answers

<p>Zeolite conditioning</p> Signup and view all the answers

<p>1 mg/l = 1 ppm</p> Signup and view all the answers

<p>The ion exchange resin method involves two stages. First, hard water is passed through a cation exchanger containing resins that replace calcium and magnesium ions with sodium or hydrogen ions. Then, the water is passed through an anion exchanger, which exchanges anions like chloride and sulfate with hydroxide ions, further reducing the hardness.</p> Signup and view all the answers

<p>Hard water can cause various boiler problems, including scale formation, sludge accumulation, corrosion, and foaming. Scale formation is a major concern as it insulates the boiler surface, reducing heat transfer efficiency and leading to higher fuel consumption. The buildup of scale can also impede water flow, increasing pressure within the boiler, and potentially leading to boiler failure.</p> Signup and view all the answers

<p>Alkalinity is the capacity of water to neutralize acids. It is mainly caused by the presence of bicarbonate (HCO3-), carbonate (CO3 2-) ions, and sometimes hydroxide (OH-) ions. When titrating with Phenolphthalein indicator, alkalinity is due to the presence of hydroxide and carbonate ions. However, Methyl orange indicator detects the presence of all three ions (hydroxide, carbonate, and bicarbonate). Alkalinity is important in water treatment because it can influence water chemistry and the effectiveness of disinfection processes.</p> Signup and view all the answers

<p>lose electrons</p> Signup and view all the answers

<p>Lithium ion battery</p> Signup and view all the answers

<p>Dry cells use a chemical reaction to produce electricity. Over time, the chemical reaction continues to occur, even when not in use. This gradually depletes the chemicals, leading to a decrease in the battery's voltage and eventually rendering it useless.</p> Signup and view all the answers

<p>Reversible cells can be recharged by applying an external voltage, allowing the chemical reactions to proceed in reverse. An example is a lead-acid battery. Irreversible cells, on the other hand, cannot be recharged once discharged. An example is a dry cell or a carbon-zinc battery.</p> Signup and view all the answers

<p>From the Nernst equation $E_{cell} = E°<em>{cell} - \frac{RT}{nF} lnQ$ , we have $E</em>{cell} = (E°<em>{Cu2+/Cu}- E°</em>{Zn2+/Zn}) - \frac{8.314 * 298}{2 * 96485} ln(\frac{0.001}{0.1})$. Solving for $E_{cell}$ gives us $E_{cell} = 1.10 V$.</p> Signup and view all the answers

<p>The Nernst equation is derived from the Gibbs free energy change for a reversible reaction. The equation relates the cell potential (E) to the standard cell potential (E°), temperature (T), Faraday's constant (F), and the reaction quotient (Q). Applications of Nernst's equation include determining the cell potential under non-standard conditions, calculating the equilibrium constant of a reaction, and understanding how the electrode potential varies with concentration and temperature.</p> Signup and view all the answers

<p>A lithium-ion battery comprises an anode, typically graphite, a cathode of lithium metal oxide, and an electrolyte solution containing lithium ions. During discharge, lithium ions move from the anode to the cathode, generating an electrical current. The process is reversed during charging. Lithium-ion batteries offer several advantages, surpassing conventional batteries due to their high energy density, long cycle life, and low self-discharge rate.</p> Signup and view all the answers

<p>Acidic environment</p> Signup and view all the answers

<p>Zinc</p> Signup and view all the answers

<p>Seawater contains dissolved salts, which act as electrolytes, increasing the conductivity of the water and accelerating the electrochemical reactions involved in corrosion. Saltwater environment also contains higher concentrations of oxygen, further promoting rust formation.</p> Signup and view all the answers

<p>The Pilling-Bedworth ratio (PBR) compares the volume of an oxide formed on a metal to the volume of the original metal. If the PBR is less than 1, the oxide layer is thin and porous, offering minimal protection against corrosion. Conversely, if the PBR is greater than 1, a thicker and more protective oxide layer forms, effectively preventing further corrosion.</p> Signup and view all the answers

<p>Electrochemical corrosion occurs when a metal surface comes in contact with an electrolyte solution. This creates an electrochemical cell, where oxidation, involving the loss of electrons, occurs at the anode, and reduction, involving the gain of electrons, takes place at the cathode. The movement of electrons and ions through the electrolyte leads to the formation of corrosion products. Factors like the presence of oxygen, moisture, and electrolytes significantly influence the rate and extent of electrochemical corrosion.</p> Signup and view all the answers

<p>Several factors can influence the rate and extent of corrosion. These include: * <strong>Nature of the metal:</strong> Metals differ in their resistance to corrosion, based on their position in the electrochemical series and their oxide layer characteristics. * <strong>Environmental factors:</strong> Oxygen, moisture, and the presence of electrolytes significantly accelerate corrosion. * <strong>Temperature:</strong> Higher temperatures generally increase corrosion rates. * <strong>Stress:</strong> Stress concentration areas can lead to more rapid corrosion. * <strong>pH:</strong> Corrosion rates are influenced by the acidity (low pH) or alkalinity (high pH) of the environment. * <strong>Microorganisms:</strong> Certain bacteria and fungi can accelerate corrosion processes. By understanding these factors, it is possible to control and prevent corrosion in various applications.</p> Signup and view all the answers

<p>Several methods can be employed to control and prevent corrosion, including: * <strong>Alloying:</strong> Modifying the composition of metals by adding other elements can enhance their resistance to corrosion. * <strong>Surface coating:</strong> Applying protective coatings like paints, varnishes, or metal plating prevents direct contact between the metal and the corrosive environment. * <strong>Cathodic protection:</strong> Introducing a sacrificial metal (like zinc) that corrodes in preference to the protected metal, effectively preventing corrosion of the primary structure. * <strong>Anodic inhibition:</strong> Adding chemicals to the environment to form a protective oxide layer on the metal surface, hindering further corrosion.</p> Signup and view all the answers

<p>Monomers</p> Signup and view all the answers