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2be6eadd-a3e9-48c1-bbde-14e07ad0e374 Reaction of Alkali metals with oxygen. Summary Generally: 4M(s) + O2(g) → 2M2O(s) alkali metal + oxygen → alkali metal oxide

d4935768-e34e-4cd5-9ab7-d70e01afe9e4 cheat sheet ap chemistry unit 9 https://k-chemistry.my.canva.site/cheat-sheet-for-ap-chemistry-unit-9 Summary

41029413-be21-4400-8048-9ee91a478c37 Catalyst: Definition SABIS Summary a substance that increases the reaction rate without itself being used up. It speeds up both forward and reverse reactions. A catalyst takes part in the reaction, but is regenerated, so it is not used up.A catalyst acts: by providing a new path of lower activation energy for reactants to follow, so the catalyzed and uncatalyzed pathways proceed simultaneously.

6c42da10-353f-4cf5-bc39-e6b1c3ba2a58 Recall the expressions for gravitational potential and kinetic energy of an object Summary Gravitational Potential Energy: Gravitational potential energy is the energy possessed by an object due to its position in a gravitational field. The expression for gravitational potential energy (PE) is given by the equation: PE = mgh where m represents the mass of the object, g represents the acceleration due to gravity, and h represents the height or vertical distance of the object from a reference point. For example, if we consider a ball of mass m that is lifted to a height h above the ground, the gravitational potential energy of the ball is given by the product of its mass, the acceleration due to gravity, and the height it is lifted to. Kinetic Energy: Kinetic energy is the energy possessed by an object due to its motion. The expression for kinetic energy (KE) is given by the equation: KE = (1/2)mv^2 where m represents the mass of the object and v represents the velocity of the object. If we consider the same ball that was lifted to a height and then released, as it falls downward, its potential energy is converted into kinetic energy. The kinetic energy of the ball is given by half the product of its mass and the square of its velocity. The expression for kinetic energy shows that the kinetic energy of an object is proportional to its mass and the square of its velocity. This means that an object with a larger mass or a higher velocity will possess more kinetic energy. It's important to note that both gravitational potential energy and kinetic energy are scalar quantities, meaning they have magnitude but no specific direction. They are both measured in units of energy, such as joules (J). In summary, the expressions for gravitational potential energy and kinetic energy provide insights into the energy possessed by an object. Gravitational potential energy is determined by the mass of the object, the acceleration due to gravity, and its height from a reference point. Kinetic energy, on the other hand, depends on the mass of the object and its velocity. Understanding these expressions helps us analyze and quantify the energy changes associated with the position and motion of objects in various scenarios.

629289b3-bb7c-4aac-8641-c28edc37e589 9. Condensation of steam Exothermic Summary

6ec8ecb0-a936-41fe-9887-942cb79f66d2 Reaction of Alkali metals with chlorine. Summary Generally: 2M (s) + Cl2(g) → 2MCl(s) alkali metal + chlorine → alkali metal chloride

92a0b8cf-eeb0-4bb2-8186-cceeef7a3480 Mole Summary A unit used in chemistry to count entities at the atomic and molecular scale. One mole contains Avogadro's number of entities (6.022 x 10^23).

K-Chemistry Pricing Plans K-Chemistry Free $ 0 0$ Free and It will Always Be Free Plan Join Exam Style Questions Offline No Mock Exams Easy and medium Questions No Mistake Cleaners Comprehensive Study Guides All Topics Worksheets Most Sold K-Chemistry PRO $ 5 5$ Every month All You need to Get the Full Mark Join Self Marking Exam Style Questions Self Marking Mock Exams Easy and medium and Hard Questions Mistake Cleaners Master Study Guides and Notes All Topics Answered Worksheets K-Chemistry Extra $ 25 25$ Every month Programs Monthly Subscription Attend all self study courses and save your progress 1 day free trial Start Free Trial Self Marking Exam Style Questions Self Marking Mock Exams Easy and medium and Hard Questions Mistake Cleaners Master Study Guides and Notes All Topics Answered Worksheets Please Read More about plana and package options , Contact us for more details if you wish before joinig.phone or whatsapp 00971561391561 You can Buy a plan each time for 1 week , Signing up means you agreed to Terms and Conditions.Take care when joining a plan that auto renews.Send the details or this page link to an adult if you wish . Please read carefully before choosing about the difference between each plan. Read about payment options Read about cancellation policy after Buying

Worksheets to practice all concepts of AP chemistry for Free AP Chemistry Worksheets Click to preview More AP Chemistry Worksheets Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 Unit 8 Unit 9 Unit 1 Topic 1 Worksheet Moles and Molar Mass Unit 1 Topic 2 Worksheet Mass Spectroscopy of Elements Unit 1 Topic 3 Worksheet Elemental Composition of Pure Substances Unit 1 Topic 4 Worksheet Elemental Composition of Pure Substances Unit 1 Topic 5 Worksheet Atomic Structure and Electron Configuration Unit 1 Topic 6 Worksheet Photoelectron Spectroscopy (PES) Unit 1 Topic 7 Worksheet Periodic Trends Unit 1 Topic 8 Worksheet Valence Electrons and Ionic Compounds

Discover the different types of bonding present in solids and liquids and how they affect the physical and chemical properties of materials. < Back Chapter 9: Bonding in Solids and Liquids Discover the different types of bonding present in solids and liquids and how they affect the physical and chemical properties of materials. Chapter 9: Bonding in Solids and Liquids - This chapter covers the different types of bonding in solids and liquids. Students will learn about metallic bonding, ionic bonding, and covalent bonding. The chapter also covers the properties of solids and liquids, including viscosity and surface tension. Previous Next

< Back Chapter 9 Prerequisite Previous Next 🌟📘 Prerequisites for Chapter 9: Rate of Reaction 📘🌟Before diving into Chapter 9, which deals with the rate of reaction, students must have a solid understanding of the following concepts:🔬 1. Basic Chemistry Concepts 🧪Understand atoms, molecules, ions, and chemical reactions.🔬 2. Collision Theory 💥Understand that reactions occur when particles collide with sufficient energy and proper orientation.🔬 3. Activation Energy 🚀Understand the concept of activation energy as the minimum energy required for a reaction to occur.🔬 4. Factors Affecting Reaction Rates 📈Understand how temperature, concentration, surface area, and catalysts affect reaction rates.🌟 20 Multiple Choice Questions for Chapter 9: Rate of Reaction 🌟What is the term for how fast reactants are consumed or products are formed in a chemical reaction? a) Reaction rate b) Activation energy c) Equilibrium constant d) EnthalpyAccording to collision theory, what must occur for a reaction to take place? a) Particles must collide with sufficient energy and proper orientation. b) Particles must collide with low energy. c) Particles must avoid colliding. d) Particles must collide with any orientation.What is the term for the minimum energy that reacting particles must have to form the activated complex? a) Reaction rate b) Activation energy c) Equilibrium constant d) EnthalpyHow does increasing the temperature affect the rate of a chemical reaction? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.How does increasing the concentration of reactants affect the rate of a chemical reaction? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.What is the term for a substance that increases the rate of a reaction without being consumed? a) Inhibitor b) Catalyst c) Solvent d) ReactantHow does increasing the surface area of a solid reactant affect the rate of a chemical reaction? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.What is the term for the highest point on the reaction path where bonds are breaking and new bonds are forming? a) Activated complex b) Transition state c) Reaction intermediate d) Both a and bHow does adding a catalyst affect the activation energy of a reaction? a) Increases activation energy. b) Decreases activation energy. c) Does not affect activation energy. d) Destroys activation energy.What is the effect of a catalyst on the rate of a reaction? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.In the rate expression rate = k[A][B], what does k represent? a) Rate of reaction b) Activation energy c) Rate constant d) Concentration of reactantsHow does increasing the pressure affect the rate of a reaction involving gases? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.What is the term for a graph that shows the change in concentration of reactants or products over time? a) Reaction coordinate diagram b) Reaction rate graph c) Concentration-time graph d) Activation energy graphWhat is the term for a short-lived, high-energy arrangement of atoms during a chemical reaction? a) Activated complex b) Transition state c) Reaction intermediate d) CatalystHow does the presence of a catalyst affect the position of equilibrium in a reaction? a) Shifts it to the right. b) Shifts it to the left. c) Does not change the position. d) Destroys the equilibrium.What is the term for the number of collisions per second between the reactant molecules? a) Collision frequency b) Reaction rate c) Activation energy d) Rate constantWhat is the effect of an inhibitor on the rate of a reaction? a) Increases the rate. b) Decreases the rate. c) Does not affect the rate. d) May increase or decrease the rate.In the reaction A -> B, if the concentration of A decreases linearly over time, what is the order of the reaction? a) Zero order b) First order c) Second order d) Third orderWhat is the term for a substance that slows down the rate of a chemical reaction? a) Inhibitor b) Catalyst c) Solvent d) ReactantIn a first-order reaction, how does the rate of reaction depend on the concentration of the reactant? a) Rate is proportional to the square of the concentration. b) Rate is inversely proportional to the concentration. c) Rate is proportional to the concentration. d) Rate is independent of the concentration.🌟 Answers 🌟a) Reaction ratea) Particles must collide with sufficient energy and proper orientation.b) Activation energya) Increases the rate.a) Increases the rate.b) Catalysta) Increases the rate.d) Both a and bb) Decreases activation energy.a) Increases the rate.c) Rate constanta) Increases the rate.c) Concentration-time grapha) Activated complexc) Does not change the position.a) Collision frequencyb) Decreases the rate.b) First ordera) Inhibitorc) Rate is proportional to the concentration.

Problems on Chapter 4 Previous All Content Next Chapter 4 SABIS Grade 10 Problems Problems on Chapter 4 📝 Lesson 24 📝 Summary Basic Ideas Problems 1. Stoichiometry and Mole-to-Mole Ratio: - Find the number of moles of products formed from a given number of moles of reactants. - Find the number of moles of reactant needed to form a given number of moles of product. Easy Questions: If 2 moles of hydrogen (H2) react with 1 mole of oxygen (O2) to form water (H2O), how many moles of water will be produced? In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of nitrogen reacts, how many moles of ammonia are produced? If 1 mole of carbon dioxide (CO2) is decomposed into its elements, how many moles of oxygen (O2) are produced? Medium Difficulty Questions: In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of iron(III) oxide are produced, how many moles of iron were needed? In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), if you want to produce 10 moles of ammonia, how many moles of nitrogen will you need? In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), if you start with 18 moles of water, how many moles of oxygen will be produced? Answers Easy Questions: If 2 moles of hydrogen (H2) react with 1 mole of oxygen (O2) to form water (H2O), how many moles of water will be produced?Answer: 2 moles of water will be produced. (Based on the balanced equation: 2H2 + O2 -> 2H2O) In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of nitrogen reacts, how many moles of ammonia are produced?Answer: 2 moles of ammonia are produced. (Based on the balanced equation: N2 + 3H2 -> 2NH3) If 1 mole of carbon dioxide (CO2) is decomposed into its elements, how many moles of oxygen (O2) are produced?Answer: 1 mole of oxygen is produced. (Based on the balanced equation: CO2 -> C + O2) Medium Difficulty Questions: In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of iron(III) oxide are produced, how many moles of iron were needed?Answer: 8 moles of iron were needed. (Based on the balanced equation: 4Fe + 3O2 -> 2Fe2O3) In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), if you want to produce 10 moles of ammonia, how many moles of nitrogen will you need?Answer: 5 moles of nitrogen are needed. (Based on the balanced equation: N2 + 3H2 -> 2NH3) In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), if you start with 18 moles of water, how many moles of oxygen will be produced?Answer: 9 moles of oxygen are produced. (Based on the balanced equation: 2H2O -> 2H2 + O2) 2. Mass Relations and Mass-to-Mass Ratio: - Write the mass ratio of a given reaction. Easy Questions: In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what is the mass ratio of hydrogen to oxygen? Answer: The mass ratio of hydrogen to oxygen is 2g:32g. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what is the mass ratio of nitrogen to hydrogen? Answer: The mass ratio of nitrogen to hydrogen is 28g:6g. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what is the mass ratio of carbon to oxygen? Answer: The mass ratio of carbon to oxygen is 12g:32g. Medium Difficulty Questions: In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what is the mass ratio of iron to oxygen? Answer: The mass ratio of iron to oxygen is 112g:96g. In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), what is the mass ratio of nitrogen to hydrogen? Answer: The mass ratio of nitrogen to hydrogen is 28g:6g. In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), what is the mass ratio of hydrogen to oxygen? Answer: The mass ratio of hydrogen to oxygen is 2g:32g. - Find the mass of the product formed from a given mass of reactant. Easy Problems: If 4 grams of hydrogen (H2) react with sufficient oxygen (O2) to form water (H2O), what is the mass of water formed? Answer: The molar mass of hydrogen (H2) is 2g/mol and that of water (H2O) is 18g/mol. Therefore, the mass of water formed is (4g H2) * (18g H2O / 2g H2) = 36g of H2O. If 28 grams of nitrogen (N2) react with sufficient hydrogen (H2) to form ammonia (NH3), what is the mass of ammonia formed? Answer: The molar mass of nitrogen (N2) is 28g/mol and that of ammonia (NH3) is 17g/mol. Therefore, the mass of ammonia formed is (28g N2) * (2 * 17g NH3 / 28g N2) = 34g of NH3. If 12 grams of carbon (C) react with sufficient oxygen (O2) to form carbon dioxide (CO2), what is the mass of carbon dioxide formed? Answer: The molar mass of carbon (C) is 12g/mol and that of carbon dioxide (CO2) is 44g/mol. Therefore, the mass of carbon dioxide formed is (12g C) * (44g CO2 / 12g C) = 44g of CO2. Difficult Problems: If 64 grams of sulfur (S8) react with sufficient oxygen (O2) to form sulfur dioxide (SO2), what is the mass of sulfur dioxide formed? Answer: The molar mass of sulfur (S8) is 256g/mol and that of sulfur dioxide (SO2) is 64g/mol. Therefore, the mass of sulfur dioxide formed is (64g S8) * (8 * 64g SO2 / 256g S8) = 128g of SO2. If 56 grams of iron (Fe) react with sufficient oxygen (O2) to form iron(III) oxide (Fe2O3), what is the mass of iron(III) oxide formed? Answer: The molar mass of iron (Fe) is 56g/mol and that of iron(III) oxide (Fe2O3) is 160g/mol. Therefore, the mass of iron(III) oxide formed is (56g Fe) * (160g Fe2O3 / 112g Fe) = 80g of Fe2O3. If 27 grams of aluminum (Al) react with sufficient oxygen (O2) to form aluminum oxide (Al2O3), what is the mass of aluminum oxide formed? Answer: The molar mass of aluminum (Al) is 27g/mol and that of aluminum oxide (Al2O3) is 102g/mol. Therefore, the mass of aluminum oxide formed is (27g Al) * (102g Al2O3 / 54g Al) = 51g of Al2O3. - Find the mass of a given number of moles of a substance. Easy Problems: What is the mass of 2 moles of hydrogen (H2)? Answer: The molar mass of hydrogen (H2) is 2g/mol. Therefore, the mass of 2 moles of hydrogen is (2 moles) * (2g/mol) = 4g. What is the mass of 1 mole of nitrogen (N2)? Answer: The molar mass of nitrogen (N2) is 28g/mol. Therefore, the mass of 1 mole of nitrogen is (1 mole) * (28g/mol) = 28g. What is the mass of 3 moles of carbon (C)? Answer: The molar mass of carbon (C) is 12g/mol. Therefore, the mass of 3 moles of carbon is (3 moles) * (12g/mol) = 36g. Difficult Problems: What is the mass of 0.5 moles of sulfur (S8)? Answer: The molar mass of sulfur (S8) is 256g/mol. Therefore, the mass of 0.5 moles of sulfur is (0.5 moles) * (256g/mol) = 128g. What is the mass of 2.5 moles of iron (Fe)? Answer: The molar mass of iron (Fe) is 56g/mol. Therefore, the mass of 2.5 moles of iron is (2.5 moles) * (56g/mol) = 140g. What is the mass of 1.5 moles of aluminum (Al)? Answer: The molar mass of aluminum (Al) is 27g/mol. Therefore, the mass of 1.5 moles of aluminum is (1.5 moles) * (27g/mol) = 40.5g. 3. Volume Relations and Volume-to-Mole Ratio: - Give the reacting ratios in moles, mass, and volume. Easy Problems: In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 2:1 in moles (2 moles of H2 react with 1 mole of O2), 2g:32g in mass, and 44.8L:22.4L in volume. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 1:3 in moles (1 mole of N2 reacts with 3 moles of H2), 28g:6g in mass, and 22.4L:67.2L in volume. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 1:1 in moles (1 mole of C reacts with 1 mole of O2), 12g:32g in mass, and 22.4L:22.4L in volume. Difficult Problems: In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 1:8 in moles (1 mole of S8 reacts with 8 moles of O2), 256g:256g in mass, and 22.4L:179.2L in volume. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 4:3 in moles (4 moles of Fe react with 3 moles of O2), 224g:96g in mass. Volume ratio is not applicable as iron is a solid. In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), what are the reacting ratios in moles, mass, and volume? Answer: The reacting ratios are 4:3 in moles (4 moles of Al react with 3 moles of O2), 108g:96g in mass. Volume ratio is not applicable as aluminum is a solid. - Find the volume of one reactant needed to react with a given number of moles of another reactant. Easy Problems: In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what volume of hydrogen is needed to react with 1 mole of oxygen at STP? Answer: The volume of 2 moles of hydrogen at STP is 44.8 L. Therefore, to react with 1 mole of oxygen, 44.8 L of hydrogen is needed. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what volume of hydrogen is needed to react with 1 mole of nitrogen at STP? Answer: The volume of 3 moles of hydrogen at STP is 67.2 L. Therefore, to react with 1 mole of nitrogen, 67.2 L of hydrogen is needed. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what volume of oxygen is needed to react with 1 mole of carbon at STP? Answer: The volume of 1 mole of oxygen at STP is 22.4 L. Therefore, to react with 1 mole of carbon, 22.4 L of oxygen is needed. Difficult Problems: In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), what volume of oxygen is needed to react with 0.5 moles of sulfur at STP? Answer: The volume of 8 moles of oxygen at STP is 179.2 L. Therefore, to react with 0.5 moles of sulfur, 89.6 L of oxygen is needed. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what volume of oxygen is needed to react with 2 moles of iron at STP? Answer: The volume of 1.5 moles of oxygen at STP is 33.6 L. Therefore, to react with 2 moles of iron, 33.6 L of oxygen is needed. In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), what volume of oxygen is needed to react with 2 moles of aluminum at STP? Answer: The volume of 1.5 moles of oxygen at STP is 33.6 L. Therefore, to react with 2 moles of aluminum, 33.6 L of oxygen is needed. finding the amount of heat released when a given mass of product is formed from the molar heat of reaction: Easy Problems: In the combustion of methane (CH4), -890.4 kJ of heat is released per mole of CH4 combusted. How much heat is released when 16 g of CH4 (approximately 1 mole) is combusted? Answer: -890.4 kJ of heat is released when 16 g of CH4 is combusted. In the combustion of hydrogen (H2) to form water (H2O), -285.8 kJ of heat is released per mole of H2 combusted. How much heat is released when 2 g of H2 (approximately 1 mole) is combusted? Answer: -285.8 kJ of heat is released when 2 g of H2 is combusted. In the combustion of carbon (C) to form carbon dioxide (CO2), -393.5 kJ of heat is released per mole of C combusted. How much heat is released when 12 g of C (approximately 1 mole) is combusted? Answer: -393.5 kJ of heat is released when 12 g of C is combusted. Difficult Problems: In the combustion of glucose (C6H12O6), -2803 kJ of heat is released per mole of glucose combusted. How much heat is released when 90 g of glucose is combusted? Answer: The molar mass of glucose is approximately 180 g/mol. Therefore, 90 g is approximately 0.5 moles. So, -1401.5 kJ of heat is released when 90 g of glucose is combusted. In the combustion of ethanol (C2H5OH), -1367 kJ of heat is released per mole of ethanol combusted. How much heat is released when 23 g of ethanol is combusted? Answer: The molar mass of ethanol is approximately 46 g/mol. Therefore, 23 g is approximately 0.5 moles. So, -683.5 kJ of heat is released when 23 g of ethanol is combusted. In the combustion of propane (C3H8), -2220 kJ of heat is released per mole of propane combusted. How much heat is released when 22 g of propane is combusted? Answer: The molar mass of propane is approximately 44 g/mol. Therefore, 22 g is approximately 0.5 moles. So, -1110 kJ of heat is released when 22 g of propane is combusted. problems about predicting excess and limiting reagents: Easy Problems: In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), if 4 moles of H2 react with 1 mole of O2, which is the limiting reagent? Answer: Oxygen (O2) is the limiting reagent because the reaction requires 2 moles of H2 for every 1 mole of O2. Therefore, there is an excess of H2. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of N2 reacts with 2 moles of H2, which is the limiting reagent? Answer: Nitrogen (N2) is the limiting reagent because the reaction requires 3 moles of H2 for every 1 mole of N2. Therefore, there is an excess of H2. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), if 1 mole of C reacts with 1 mole of O2, which is the limiting reagent? Answer: Neither is the limiting reagent because the reaction requires 1 mole of C for every 1 mole of O2. Therefore, there is no excess reagent. Medium Difficulty Problems: In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), if 1 mole of S8 reacts with 6 moles of O2, which is the limiting reagent? Answer: Sulfur (S8) is the limiting reagent because the reaction requires 8 moles of O2 for every 1 mole of S8. Therefore, there is an excess of O2. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of Fe react with 2 moles of O2, which is the limiting reagent? Answer: Oxygen (O2) is the limiting reagent because the reaction requires 3 moles of O2 for every 4 moles of Fe. Therefore, there is an excess of Fe. In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), if 4 moles of Al react with 2 moles of O2, which is the limiting reagent? Answer: Aluminum (Al) is the limiting reagent because the reaction requires 3 moles of O2 for every 4 moles of Al. Therefore, there is an excess of O2. Difficult Problems: In the reaction of glucose (C6H12O6) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C6H12O6 reacts with 5 moles of O2, which is the limiting reagent? Answer: Oxygen (O2) is the limiting reagent because the reaction requires 6 moles of O2 for every 1 mole of C6H12O6. Therefore, there is an excess of C6H12O6. In the reaction of ethanol (C2H5OH) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C2H5OH reacts with 2 moles of O2, which is the limiting reagent? Answer: Ethanol (C2H5OH) is the limiting reagent because the reaction requires 3 moles of O2 for every 1 mole of C2H5OH. Therefore, there is an excess of O2. In the reaction of propane (C3H8) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C3H8 reacts with 4 moles of O2, which is the limiting reagent? Answer: Propane (C3H8) is the limiting reagent because the reaction requires 5 moles of O2 for every 1 mole of C3H8. Therefore, there is an excess of O2.