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7c5c9f6b-7b54-4d7d-9124-29b699551fff < Back Previous Next A hot air balloon rises as gas expands with heat Bicycle floor pump Moving particles of gas colliding with each other and the container walls Move to Another Chapter Atoms, Elements & Compounds Stoichiometry Electrochemistry Chemical Energetics Chemical Reactions Acids, Bases & Salts The Periodic Table Metals Chemistry of the Environment Organic Chemistry Experimental Techniques & Chemical Analysis States of Matter Next Topic

Lesson 23 Chapter 6 SABIS Grade 12 Part 3 Lesson 23 Molar Enthalpy: Counting Energy, One Mole at a Time! 🧪🔥 What's up, future chemists? Ready to dig into another hot topic? Today we're breaking down molar enthalpy—a way to talk about energy changes that happen when you've got one mole of a substance involved in a reaction. Let's dive in! 🏊♀️ What Is Molar Enthalpy? 🤔 Molar enthalpy (Δ H ) is the heat absorbed or released per mole of a substance during a chemical reaction or physical process. It's like the "per person" ticket price at a concert, but for atoms and molecules! 🎫 Why Is It Useful? 💡 Knowing the molar enthalpy helps chemists compare different reactions on a mole-for-mole basis. It standardizes the way we look at heat changes, making it easier to predict outcomes in various conditions. 🌡️ Units & Symbols 📏 The units for molar enthalpy are usually J/molJ/mol or kJ/molkJ/mol. You'll often see it expressed as: Δ Hf ∘ = Molar enthalpy of formation Δ Hc ∘ = Molar enthalpy of combustion The "°" symbol means the values are measured under standard conditions (1 atm and 25°C). Types of Molar Enthalpy 📚 Molar Enthalpy of Formation (Δ Hf ∘) : The heat change when one mole of a compound forms from its elements. Molar Enthalpy of Combustion (Δ Hc ∘) : The heat released when one mole of a substance completely burns in oxygen. Molar Enthalpy of Fusion (Δ H fus) : The heat needed to melt one mole of a solid to a liquid. Calculations and Equations 🧮 To calculate molar enthalpy for a reaction, use the equation: Δ H rxn=∑(Δ Hf ∘ of products)−∑(Δ Hf ∘ of reactants) You sum up the Δ Hf ∘ values for all products and subtract the sum of theΔ Hf ∘ values for all reactants. Practical Applications 🌍 Energy Production : Understanding molar enthalpies helps in optimizing fuel efficiency. Pharmaceuticals : Helps in synthesizing new medicines in the most energy-efficient way. Get Hands-On! 🧪 Calorimeter Experiments : Measure the heat changes in simple reactions and then calculate the molar enthalpy. Thermochemical Equations : Practice writing equations with Δ H values to get a feel for how molar enthalpy fits into the bigger chemical picture. So, that's the 411 on molar enthalpy! Use this concept to level up your chemistry game and make those reactions a piece of cake. 🍰 Keep asking questions, keep experimenting, and keep learning! 🎉 Next Lesson Previous Lesson

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e5e29b29-1207-451f-9aba-95dd1eadc2b2 Boiling an egg in boiling water for two minutes, then cooling the water Summary Chemical

Lesson 33 Chapter 6 SABIS Grade 10 Part 3 Lesson 33 231. Demonstration: Sublimation: Examples of solids that can sublime at room temperature: 1) Solid iodine, I2 (s) 2) Dry ice or solid carbon dioxide CO2 (s) 3) Any ammonium compound as ammonium chloride, NH4Cl and ammonium bromide, NH4Br232. Demonstration: Simple Distillation233. Demonstration: Fractional distillation. Discuss briefly: fractional distillation of liquefied air and fractional distillation of crude oil.234. Demonstration: Separating funnel235. Adsorption: means sticking to the surface.236. Adsorption: sticking of the particles of one material on the surface of another. Examples of adsorbing substances: Silica gel: adsorbs water vapor, Charcoal: adsorbs gases with strong odor and removes colored impurities from a solution237. Demonstration: Chromatography. It is the technique used to separate different compounds, especially those that can be easily destroyed by heat or chemicals. It can be used to separate colored components as: 1) Green liquid obtained by squashing green leaves. 2) Black ink. The property that carries the liquid up the paper is capillary action.238. Demonstration: Crystallization239. Alcohol is flammable, therefore it cannot be heated directly. To heat alcohol, we should use a steam bath or an electric heater.240. If you need to collect sugar from sugar alcohol solution heat the solution using an electric heater to crystallization point. Leave the solution to cool and crystals to form. Filter off the crystals.241. Vapor pressure and temperature are proportional NOT directly proportional. At the same temperature, the vapor pressure is the SAME. For the same liquid, the only factor affecting the pressure of the liquid is the temperature.242. Minimum conditions for liquid molecules to vaporize: 1) Molecules are supposed to be on the surface. 2) Molecules are supposed to have an average kinetic energy greater than the energy keeping the molecules in the liquid state.243. Water has a vapor pressure of 17.5 mmHg at 20oC. Which of the following will increase the vapor pressure of water? a) Transferring water to a larger container. b) Cooling water to 10oC c) Taking the container to the top of the mountain. d) Heating the water to 32oC244. Boiling point: is the temperature at which the liquid vaporizes anywhere in the solution.245. At the boiling point: a. Vapor pressure is equal to the surrounding pressure. b. Bubbles of vapor can form anywhere within the liquid. c. Molecules escape from the surface of the liquid to enter the gas phase as vapor (this also happens at room temperature). d. With increasing altitude, atmospheric pressure decreases and so does boiling point.246. Normal boiling point: is the temperature at which the vapor pressure is exactly 1 atm or 760 mmHg.247. Molar heat of fusion: is the energy required to change one mole of a substance from solid to liquid at the same temperature and constant pressure.248. General equation for Molar heat of vaporization: X (l) + heat ⇌ X (g)249. General equation for Molar heat of condensation: X (g) ⇌ X (l) + heat250. In general, a substance that has a higher boiling point is expected to have a Here are the points from 251 to 260:251. An aqueous solution is one in which the solvent is water.252. Salt and water is an example of aqueous solutions where the solute is a solid.253. Alcohol and water is an example of aqueous solutions where the solute is a liquid.254. Ammonia and water is an example of aqueous solutions where the solute is a gas.255. Concentration: relative amounts of solute and solvent.256. Molar concentration (Molarity): is the number of moles of solute per liter (dm3) of solution. (the relative amounts of solute and solution)257. Concentration of a given solution does not change if solution is split into fractions.258. Relationships between n, V, C and m, M, V, C: n = CV, 𝐂 = 𝐦/𝐕, 𝐕 = 𝐦/𝐂, m = n × M, m = CVM, 𝐌 = 𝐦/𝐂𝐕259. Preparing solutions with given concentrations.260. A 2 L bottle of 0.35 M solution is split into ten containers of 100ml capacity. What is the concentration of the solution in each of the new containers? a) 0.75 M b) 0.0035 M c) 2.0 M d) 0.35 M e) 100 M

046f1805-79e0-4c9e-acb6-58f89c358f76 Cooling Curve Summary A graphical representation of the relationship between temperature and time as a substance cools.

SABIS Grade 11 Chapter 1 Topqs

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2.1. Measurement 2.2.1. Criteria of purity 2.2.2. Methods of purification Experimental Techniques IGCSE CAMBRIDGE Presentation Notes : 2.1 Measurement 2.2 Criteria of Purity , Chromatography 2.3 Methods of Purification List of Topics

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