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Post a LessonAnswered on 21 Feb Learn Chemical effects of Electric Current
Sadika
It is dangerous to touch electrical appliances with wet hands due to the increased conductivity of water. When water is present on the skin, it acts as a conductor of electricity. When a person with wet hands touches an electrical appliance, the water on the skin provides a pathway for the electrical current to flow through the body.
Electricity always seeks the path of least resistance, and water present on the skin significantly reduces the body's resistance to electrical current. This can lead to a phenomenon known as electric shock, which occurs when electric current passes through the body. Electric shock can cause a range of injuries, from mild discomfort to severe burns, cardiac arrest, and even death, depending on the severity of the shock and the path the current takes through the body.
Additionally, moisture or water on electrical appliances can increase the risk of short circuits or electrical fires, which can further escalate the danger.
To avoid the risk of electric shock, it's essential to keep hands dry when handling electrical appliances and to ensure that appliances are not used near water sources. Additionally, it's crucial to follow proper electrical safety practices, such as using grounded outlets, avoiding overloading electrical circuits, and keeping electrical appliances away from water.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
Substances that can make any liquid a good conductor of electricity are typically electrolytes. Electrolytes are substances that ionize when dissolved in water or other solvents, producing positively and negatively charged ions that can carry electrical current through the solution. Common examples of substances that can make liquids conductive include:
Ionic Compounds: Ionic compounds, such as salts (e.g., sodium chloride, potassium chloride) and acids (e.g., hydrochloric acid, sulfuric acid), dissociate into ions when dissolved in water, making the solution conductive.
Acids and Bases: Strong acids (e.g., hydrochloric acid) and strong bases (e.g., sodium hydroxide) dissociate completely in water, producing ions and making the solution conductive.
Some Metal Compounds: Some metal compounds, such as metallic salts (e.g., copper sulfate, iron(II) chloride), can also dissociate into ions and make the solution conductive.
Ionized Gases: In some cases, gases can also become conductive when ionized. For example, water can become conductive when exposed to ionizing radiation or when mixed with certain gases like hydrogen chloride.
These substances increase the concentration of ions in the solution, allowing electrical current to flow more easily through the liquid. However, it's important to note that not all liquids are conductive, and the presence of these substances is necessary to make a liquid capable of conducting electricity.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
The part of a bulb that glows is called the filament. The filament is typically made of tungsten wire and is located within the bulb's glass envelope. When an electric current passes through the filament, it heats up due to its resistance, reaching temperatures where it emits visible light. This glowing filament is what produces the light output of an incandescent bulb.
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Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
Distilled water, in its pure form, does not conduct electricity well. This is because it lacks the ions necessary for conducting electric current. Normal water becomes a conductor of electricity due to the presence of minerals and impurities, which dissociate into ions. These ions are the charge carriers that allow electricity to flow through the water.
Distillation removes these impurities and minerals, leaving almost pure water composed of H2O molecules without free ions. Therefore, without ions to carry the charge, distilled water has a very high resistance to electrical current. However, it's important to note that it's very difficult to maintain water in a completely pure state. Even slight contamination with ions can make distilled water conductive to some degree.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
Testing whether liquids conduct electricity can be done using a simple experimental setup. Here's a basic method to determine if a liquid is a conductor or an insulator of electricity:
Set Up the Circuit:
Introduce the Liquid:
Observation:
Pure or distilled water should theoretically not conduct electricity because it lacks ions. However, common tap water, seawater, and many other liquids contain ions that can conduct electricity. The conductivity test can vary significantly based on the concentration of ions in the liquid.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
A bulb glows when an electric current passes through it due to the conversion of electrical energy into light and heat energy, a process primarily facilitated by the bulb's filament. The most common type of bulb used to illustrate this principle is the incandescent bulb, although the basic idea of converting electrical energy into light (and heat) applies to other types of bulbs, like LEDs and fluorescent lights, albeit through different mechanisms. Here’s how it works in an incandescent bulb:
Filament and Resistance: At the heart of an incandescent bulb is a thin filament typically made of tungsten. When electrical current is passed through the filament, the filament's resistance to the electrical current causes it to heat up.
Heat and Light: The resistance causes the filament to get so hot that it glows, emitting light. The temperature of the tungsten filament in an incandescent bulb can reach up to about 2,500 to 3,000 degrees Celsius (about 4,532 to 5,432 degrees Fahrenheit), producing a broad spectrum of light that includes visible light, infrared (heat), and some ultraviolet light.
Thermal Radiation: The glowing of the filament is a result of thermal radiation. Objects at high temperatures emit electromagnetic radiation across a spectrum. For the temperatures achieved by the tungsten filament, a significant portion of this radiation is in the visible spectrum, making the filament visibly glow.
The electrical energy supplied to the bulb is converted into heat due to the resistance offered by the filament. This is described by Joule's law, which states that the heat generated in a conductor by an electric current is proportional to the square of the current, the resistance of the conductor, and the time for which the current flows.
A portion of this heat then further converts into light energy, making the bulb glow. However, it's worth noting that incandescent bulbs are not very energy-efficient, as the majority of the electrical energy (about 90-95%) is converted into heat rather than light.
LED (Light Emitting Diode): In LED bulbs, electrons recombine with electron holes within the device, releasing energy in the form of photons. This process is called electroluminescence, and the color of the light (corresponding to the energy of the photons) is determined by the specific energy band gap of the semiconductor material used in the LED. LEDs are more energy-efficient than incandescent bulbs because a greater portion of the electrical energy is converted directly into light.
Fluorescent Lights: These contain a mercury vapor that emits ultraviolet (UV) light when an electric current causes the gas to glow. The UV light then stimulates a fluorescent coating on the inside of the bulb to emit visible light. Fluorescent lights are more energy-efficient than incandescent lights but less so than LEDs.
In summary, a bulb glows on passing current due to the conversion of electrical energy into light (and heat), with the specific mechanism of conversion depending on the type of bulb.
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Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
The chemical effect of electricity involves the triggering of chemical reactions by passing an electric current through a conductor or a solution. This process, known as electrolysis when it involves a liquid electrolyte, leads to the decomposition of chemical compounds and the liberation or deposition of elements. The chemical effects of electricity are fundamental to various industrial processes, environmental management, and everyday applications. Here are some examples and explanations of the chemical effects of electricity:
One of the most straightforward examples of the chemical effect of electricity is the electrolysis of water. When an electric current is passed through water (usually containing an electrolyte, like salt, to improve conductivity), water decomposes into oxygen and hydrogen gases. At the cathode (negative electrode), hydrogen ions (H+) gain electrons (reduction) to form hydrogen gas (H2), and at the anode (positive electrode), water molecules lose electrons (oxidation) to form oxygen gas (O2) and hydrogen ions (H+). The overall reaction is:
2H2O(l)→2H2(g)+O2(g)2H2O(l)→2H2(g)+O2(g)
Electroplating is a process that uses electrical current to reduce dissolved metal cations so that they form a thin coherent metal coating on an electrode. The object to be plated is placed at the cathode of an electrolytic cell, and the metal to be plated onto the object is placed at the anode or in the electrolyte solution. For example, silver plating on copper:
Ag+(aq)+e−→Ag(s)Ag+(aq)+e−→Ag(s)
This is a method used for refining metals, typically copper. It involves using an electrolytic cell to purify the crude metal. The impure metal is made the anode, and a pure strip of the metal is made the cathode. The electrolyte solution contains ions of the metal to be purified. Upon passing an electric current, pure metal from the anode dissolves into the electrolyte and is then deposited onto the cathode, leaving impurities behind.
Batteries convert chemical energy into electrical energy through redox reactions. In a simple zinc-carbon battery, for example, zinc is oxidized at the anode, and manganese dioxide is reduced at the cathode, producing a flow of electrons that provides electrical power to connected devices.
These devices use the chemical effect of electricity to perform non-spontaneous chemical reactions. An example is the production of chlorine gas and sodium hydroxide from brine (saltwater) in the chlor-alkali process:
At the anode: 2Cl−→Cl2(g)+2e−2Cl−→Cl2(g)+2e−
At the cathode: 2H2O(l)+2e−→H2(g)+2OH−2H2O(l)+2e−→H2(g)+2OH−
Overall process: 2NaCl+2H2O→2NaOH+H2+Cl22NaCl+2H2O→2NaOH+H2+Cl2
These examples highlight the importance of the chemical effect of electricity in various scientific, industrial, and technological applications, demonstrating how it can be harnessed to drive chemical reactions, refine metals, deposit materials, and generate useful products.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
Testing materials to determine whether they are insulators or conductors of electricity can be performed using a variety of methods, but two common approaches involve the use of simple electrical circuits and multimeters. These methods help in understanding how well a material can conduct electric current.
This method involves creating a basic circuit to see if a material can complete the circuit, allowing electricity to flow. Here's how you can perform it:
Set Up the Circuit: Connect the light bulb or LED to the battery using the wires to create a simple circuit. Ensure that the circuit is working by confirming that the light bulb lights up or the LED glows when the circuit is closed.
Introduce the Material: Open the circuit and insert the material between the two ends of the circuit where you've opened it. Essentially, you're using the material as a bridge to complete the circuit.
Observation:
A more precise method involves using a multimeter, an instrument designed to measure electric current (amperage), voltage, and sometimes resistance.
Set the Multimeter: Set the multimeter to measure resistance (ohms). Many multimeters have an audible continuity feature that beeps if there's a connection (low resistance).
Measure the Material: Touch the multimeter's probes to two opposite ends or sides of the material.
Observation:
These methods can effectively distinguish between conductors and insulators, aiding in the understanding of materials' electrical properties for educational, hobbyist, or professional purposes.
Answered on 21 Feb Learn Chemical effects of Electric Current
Sadika
a. True. Rubber is an insulator.
b. False. Electroplating is a process used to prevent rusting by coating a metal object with a layer of a different metal that is less likely to corrode.
c. Conduct. Vinegar can conduct electricity because it is an aqueous solution of acetic acid and contains ions that allow it to conduct electricity.
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Answered on 29/07/2020 Learn Chemical effects of Electric Current
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