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7c4940f5-dbcc-4302-93aa-68d154e137b6 Mathematical Representation Summary P1V1 = P2V2, which signifies that the product of initial pressure and volume equals the product of final pressure and volume.

How fast the gas diffuses depends on two factors 1 The mass of the particles The rate of diffusion of gases Gases diffuse because the particles collide with other particles, and bounce off in all directions . if you do not know what exactly diffusion means click here first Note that gases do not all diffuse at the same rate. The speed with which the gases diffuse depends on these two factors: 1 The mass of the particles The particles in hydrogen chloride gas are twice as heavy as those in ammonia gas. Cotton wool soaked in ammonia solution is put into one end of a long tube (at A below). It gives off ammonia gas.  At the same time, cotton wool soaked in hydrochloric acid is put into the other end of the tube (at B). It gives off hydrogen chloride gas.  The gases diffuse along the tube. White smoke forms where they meet: The white smoke forms closer to B. So the ammonia particles have travelled further than the hydrogen chloride particles – which means they have travelled faster. The lower the mass of its particles, the faster a gas will diffuse. When particles collide and bounce away, the lighter particles will bounce further. The particles in the two gases above are molecules. The mass of a molecule is called its relative molecular mass. So The lower its relative molecular mass, the faster a gas will diffuse. 2 The temperature When a gas is heated its particles take in heat energy, and move faster. They collide with more energy, and bounce further away. So the gas diffuses faster. The higher the temperature, the faster a gas will diffuse. Diffusion Download as PDF

fde85c58-101d-46eb-9a7c-0451dd29502c understand that chemical reactions are accompanied by enthalpy changes and these changes can be exothermic (ΔH is negative) or endothermic (ΔH is positive) Summary Chemical reactions are accompanied by enthalpy changes, which refer to the heat energy exchanged during the reaction. Enthalpy (H) represents the total energy content of a system, including both internal energy and the energy associated with pressure and volume. By studying enthalpy changes, we gain insights into the energy flow and transformations occurring in chemical reactions. Enthalpy changes can be classified as exothermic or endothermic based on the sign of ΔH, which represents the change in enthalpy. In exothermic reactions, the products have lower enthalpy than the reactants, resulting in a negative ΔH value. This negative ΔH indicates that the reaction releases heat energy to the surroundings. For example, when wood burns, it undergoes an exothermic reaction. The reactants (wood and oxygen) have a higher enthalpy than the products (carbon dioxide, water, and heat), leading to a negative ΔH. The heat released during this reaction warms up the surroundings, making it feel warm and giving off light. On the other hand, endothermic reactions have products with higher enthalpy than the reactants, resulting in a positive ΔH value. This positive ΔH indicates that the reaction absorbs heat energy from the surroundings to proceed. An example of an endothermic reaction is the process of photosynthesis in plants. During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen using energy from sunlight. This reaction requires energy input, which is absorbed from the surroundings, resulting in a positive ΔH. Understanding whether a reaction is exothermic or endothermic is crucial for various applications. It helps us predict the energy changes associated with reactions and understand their impact on the surroundings. Exothermic reactions often have practical applications such as combustion for energy generation, while endothermic reactions are commonly utilized in processes like thermal decomposition or cooling systems. In summary, enthalpy changes in chemical reactions can be exothermic (ΔH is negative) or endothermic (ΔH is positive). Exothermic reactions release heat energy to the surroundings, while endothermic reactions absorb heat energy from the surroundings. By recognizing and understanding these enthalpy changes, we gain insights into the energy dynamics of chemical reactions and their significance in various real-world processes.

6db8ab25-5121-4066-aa23-2ee26c0e25fa Reading Equations Summary Using masses of reactants and products

2f1a747a-a4ca-4373-9f32-39d6958d7e36 Effect of changing concentration on rate of reaction: Summary Increasing the concentration of a reactant increases the number of particles in a given volume thus the reacting particles will collide more frequently so the number of collisions will increase per unit time, thus rate of reaction increases.

STP, Volume Ratios, Energy in Reactions, and Limiting Reagents Chapter 4 SABIS Grade 10 Part 4 STP, Volume Ratios, Energy in Reactions, and Limiting Reagents ✅ Lesson 19: ✅ STP, Volume Ratios, Energy in Reactions, and Limiting Reagents Hello learners! 🌞🎒 Today's chemistry class is going to be a thrilling ride as we explore concepts like Standard Temperature and Pressure (STP), stoichiometric calculations, and limiting reagents. Buckle up and get ready! 🚀🔬💡 Prerequisite Material Quiz 📚🧠 What does STP stand for? What are the conditions for STP? True or False: At STP, 1.00 mole of any gas occupies 22.4 dm³. How much percentage of air is oxygen gas by volume? What is a limiting reagent in a chemical reaction? Can the volume ratio at STP be used for any given reaction equation? True or False: The limiting reagent determines how much of the other reactants will be consumed in a chemical reaction. Can we write an equation including the energy required or released? True or False: A limiting reagent gets completely used up in a chemical reaction. Can we solve problems using the volume ratio? (Answers at the end of the lesson) Explanation: STP, Volume Ratios, Energy in Reactions, and Limiting Reagents 🧐👩🔬 Standard Temperature and Pressure (STP) STP is a common set of conditions for gases defined as 0 degrees Celsius and 1.00 atmosphere pressure. Under these conditions, any gas will have a volume of 22.4 dm³ per mole. Volume Ratios In gas reactions at STP, the volumes of gases involved can be directly related to the coefficients in the balanced equation. These are the volume ratios. Energy in Reactions Chemical reactions either absorb or release energy. We can represent this energy change in the chemical equation. Limiting Reagents In a chemical reaction, the limiting reagent is the substance that gets completely consumed and determines the maximum amount of product that can be formed. Examples 🌍🔬🔎 STP and volume ratios : In the reaction 2H₂(g) + O₂(g) → 2H₂O(g), the volume ratio of hydrogen to oxygen to water vapor is 2:1:2. If we start with 44.8 dm³ of hydrogen gas at STP, we would expect to produce 44.8 dm³ of water vapor, assuming oxygen is not the limiting reagent. Energy in reactions : In the combustion of methane (exothermic reaction), energy is released: CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g) + energy. Limiting reagents : If we react 4 moles of hydrogen gas with 1 mole of nitrogen gas according to the equation N₂(g) + 3H₂(g) → 2NH₃(g), hydrogen is the limiting reagent. It will be completely consumed and determine the maximum amount of ammonia that can be produced (2 moles). Post-lesson MCQs 📝✅ True or False: At STP, all gases have the same volume per mole. What is the volume ratio of hydrogen to oxygen in the balanced equation for the formation of water? Can energy be a product in a chemical reaction? True or False: The limiting reagent in a reaction is always the reactant with the smallest amount of moles. How do we determine the mass of the excess reagent left in a reaction? (Answers at the end of the lesson) Answers Prerequisite Material Quiz : Standard Temperature and Pressure, 0 degrees Celsius and 1.00 atmosphere pressure, True, 20%, The substance that gets completely consumed in a reaction, Yes, True, Yes, True, Yes. Post-lesson MCQs : True, 2:1, Yes, energy can be a product in exothermic reactions, False, the limiting reagent is the substance that is completely consumed in a reaction, not necessarily the one with the smallest amount of moles, By subtracting the amount of the reagent that reacted from the total amount initially present. Complete the Questions : The volume ratio at STP for a given reaction equation is directly related to the coefficients of the gases in the balanced equation. An example of an endothermic reaction is the thermal decomposition of calcium carbonate: CaCO₃(s) + energy → CaO(s) + CO₂(g). The volume of 2 moles of nitrogen gas at STP is 2 moles × 22.4 dm³/mole = 44.8 dm³. Stoichiometric calculations involve using the coefficients in a balanced equation to calculate quantities of reactants or products. It can involve mole, mass, volume, or energy ratios. The limiting reagent is determined by comparing the amount of products each reactant could produce if it were completely consumed. The reactant that produces the least amount of product is the limiting reagent.

26b7b582-16a5-466e-adf7-f5ec8d0d28bd Most chemical reactions proceed by sequences of steps, each involving only two-particle collisions. Summary

SABIS Grade 11 Chapter 1 Homework 2

5c0eaceb-a1c5-4a58-8ba5-d19141e50b5c < Back Previous Next 💎🔬 Purification 🔬💎 Purification involves using electrolysis to remove impurities from a metal. For instance, in the purification of copper: The cathode (-ve electrode) is pure copper. The anode (+ve electrode) is impure copper. The electrolyte is aqueous copper (II) sulfate. During electrolysis, copper ions (Cu2+) in the electrolyte are reduced (gain electrons) at the cathode and become solid copper atoms. Meanwhile, solid copper atoms at the anode are oxidized (lose electrons) and become copper ions (Cu2+), entering the electrolyte. This maintains the electrolyte's concentration, as the ions being deposited on the cathode are replaced by the ions from the anode. Any impurities in the anode copper do not dissolve and fall to the bottom. ⚗️🧪 Electroplating 🧪⚗️ Electroplating is a process that uses electrolysis to coat a metal object with a thin layer of another metal. The primary purposes of electroplating are to enhance the object's appearance and to protect it from corrosion. In a typical electroplating process: The cathode (-ve electrode) is the object to be electroplated. The anode (+ve electrode) is the metal used for coating (for example, silver). The electrolyte is a solution containing ions of the metal used for coating (for example, silver nitrate). As electrolysis proceeds, metal ions from the electrolyte are reduced at the cathode and become solid metal atoms, adhering to the object's surface. Meanwhile, at the anode, the metal is oxidized and releases ions into the electrolyte, maintaining its concentration. It's crucial to ensure the object to be electroplated is clean and entirely immersed in the electrolyte. Also, rotating it can help achieve an even coating. Regarding your reference to a past paper question (Specimen 2023, 2, q30), could you provide more context or the actual question? Unfortunately, I can't access specific past papers beyond my knowledge cut-off in September 2021. However, I'd be more than happy to help if you could provide more details about the question! Press Next for the next lesson Electricity Lesson 3 Next Topic

8bfcf45c-0f02-4192-a879-a9a474f59d01 Atomic Structure Summary Nuclear Atom : A nuclear atom is an atom with subatomic particles and a nucleus. Most of it is empty space. Atomic Boundaries : Atoms do not have specific boundaries. Atomic Diameter : The atomic diameter is the distance between two adjacent nuclei. It is in the order of 10^-10 m and it is about 10^4 times the diameter of the nucleus. Nuclear Diameter : The nuclear diameter is in the order of 10^-14 m. Subatomic Particles : Subatomic particles are electrons, protons, and neutrons. Atomic Nucleus : The atomic nucleus contains protons and neutrons (collectively known as nucleons). Comparison Between Subatomic Particles : Proton: +1 charge, 1 amu mass, located inside the nucleus. Neutron: 0 charge, 1 amu mass, located inside the nucleus. Electron: -1 charge, 1/1840 mass of 1 proton, located around the nucleus. Nuclear Atom : In a nuclear atom, the number of positive protons is equal to the number of negative electrons. Nuclear Charge : The nucleus is positively charged since it contains positive protons and neutral neutrons. Atomic Mass : The mass of an atom is concentrated in its nucleus; electrons have negligible mass compared to the nucleus. Neutrons : Neutrons help in binding the nucleus together (prevent protons from repelling each other). Nuclei of Same Element : Nuclei of the same element have the same atomic number (# of protons) and the same nuclear charge Nuclear Atom : Picture an atom as a tiny solar system. The nucleus is the sun, and the electrons are planets orbiting around it. But unlike our solar system, most of an atom is just empty space. It's like if the sun was in New York and the nearest planet was in Los Angeles! Atomic Boundaries : Atoms are like social butterflies. They don't have specific boundaries and are always ready to interact with their neighbors. It's like being at a party where everyone is mingling freely. Atomic Diameter : The atomic diameter is the distance between two adjacent atoms, like two friends standing shoulder to shoulder. It's incredibly small, about 10^-10 meters, which is a hundred million times smaller than the width of a human hair! Nuclear Diameter : The nuclear diameter is even smaller, about 10^-14 meters. That's like comparing the size of a marble to the size of the Earth! Subatomic Particles : Atoms are made up of even tinier particles: protons, neutrons, and electrons. It's like a Lego set, where the individual pieces (subatomic particles) come together to build the final product (the atom). Atomic Nucleus : The atomic nucleus is like the heart of the atom. It's where the protons and neutrons (collectively known as nucleons) live. It's the control center, holding the atom together and defining its identity. Comparison Between Subatomic Particles : Proton: Imagine protons as positive little suns residing in the nucleus. Neutron: Neutrons are the peacekeepers of the atom. They have no charge and hang out in the nucleus, helping to keep the protons from pushing each other away. Electron: Electrons are like speedy little planets orbiting the nucleus. They carry a negative charge and are incredibly light, with a mass about 1/1840 of a proton. Nuclear Atom : In a nuclear atom, the number of positive protons is equal to the number of negative electrons. It's like a perfectly balanced seesaw, with the same weight on both sides. Nuclear Charge : The nucleus carries a positive charge, thanks to the protons it houses. It's like a positive magnet at the center of the atom. Atomic Mass : The mass of an atom is concentrated in its nucleus, just like a peach pit holds most of the peach's weight. Electrons are so light, their mass is almost negligible. Neutrons : Neutrons are like the glue of the atom. They help hold the nucleus together and prevent the protons from repelling each other, just like a mediator in a heated debate. Nuclei of Same Element : Nuclei of the same element have the same number of protons and the same nuclear charge. It's like having a unique ID or barcode that identifies each element.

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