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General physical properties of non-metals: brittle, do not have a luster do not conduct heat or electricity Grade 10 SABIS ​

Recognize an endothermic/exothermic process, basing on knowledge and lab experience Grade 10 SABIS ​ Endothermic Processes: Melting ice or any solid substance. Evaporation of water or any liquid. Photosynthesis in plants, where sunlight is converted into chemical energy. Dissolving ammonium nitrate in water. Decomposition of limestone into lime and carbon dioxide upon heating. Electrolysis of water to produce hydrogen and oxygen gas. Absorption of heat by a cold pack to provide a cooling effect. Cooking food in an oven, where heat is absorbed by the food. The process of converting liquid water into steam. Dissolving barium hydroxide octahydrate in water. Exothermic Processes: Combustion of wood or any fuel, releasing heat and light. Formation of rust (oxidation of iron) with the release of heat. Neutralization of an acid with a base, such as hydrochloric acid and sodium hydroxide. Respiration in living organisms, where energy is released from glucose. Reaction between vinegar (acetic acid) and baking soda (sodium bicarbonate), resulting in the release of carbon dioxide gas. Reaction between sodium and chlorine to form sodium chloride, releasing heat and light. Freezing of water, where heat is released to the surroundings. Exothermic polymerization reactions, such as the curing of epoxy resin. Formation of precipitates during double displacement reactions, accompanied by the release of energy. Formation of bonds in exothermic chemical reactions, such as the reaction between hydrogen and oxygen to form water.

Dissolving salt into water to make a solution Grade 10 SABIS SABIS Physical

Coefficients Grade 10 SABIS SABIS The numbers placed before the reactants and products in a chemical equation, indicating how many molecules or atoms are involved.

Reaction of Alkali metals with oxygen. Grade 10 SABIS ​ Generally: 4M(s) + O2(g) → 2M2O(s) alkali metal + oxygen → alkali metal oxide

Standard Temperature and Pressure (STP) Grade 10 SABIS SABIS 0⁰C and 1.00 atm pressure

Convenient Reaction Ratio Grade 10 SABIS SABIS The ratio in which reactants combine or react to form products. It is often based on the coefficients in the balanced chemical equation and is used to simplify stoichiometric calculations.

cm³ Grade 10 SABIS SABIS A unit of volume equal to one cubic centimeter, equivalent to 1 milliliter.

Know that in for exothermic reactions H products < H reactants, ∆ H< 0 and reaction releases energy Grade 10 SABIS ​ In chemical reactions, an exothermic reaction is one that releases energy to the surroundings. It is characterized by the fact that the enthalpy (H) of the products is less than the enthalpy of the reactants. This change in enthalpy (∆H) is negative, indicating that energy is released during the reaction. To understand exothermic reactions, let's consider an everyday example: the combustion of a candle. When you light a candle, the wax reacts with oxygen in the air, and an exothermic reaction occurs. The energy stored in the wax is released as heat and light, producing a flame. In an exothermic reaction, the potential energy of the products is lower than that of the reactants. This means that the reactants have a higher energy level compared to the products. As the reaction progresses, energy is released to the surroundings, resulting in a decrease in potential energy. On a potential energy diagram for an exothermic reaction, the reactants are represented at a higher energy level compared to the products. The curve starts at a higher point (representing the energy of the reactants) and gradually decreases (representing the decrease in potential energy) as the reaction proceeds towards the products. The difference in potential energy between the reactants and products is the amount of energy released to the surroundings. The negative value of ∆H indicates that the reaction releases energy. This energy can be in the form of heat, light, or any other form of energy. In the case of the candle combustion example, the released energy is in the form of heat and light from the burning flame. Exothermic reactions are crucial in various processes. For instance, the combustion of fuels, such as gasoline in car engines or natural gas in stoves, is exothermic. The energy released during combustion is harnessed to perform useful work, such as powering vehicles or heating homes. Another example is the process of respiration in living organisms. Through cellular respiration, energy is released from glucose and other molecules, providing the necessary energy for cellular functions and activities. Exothermic reactions also play a role in many natural phenomena, such as the formation of crystals, the release of energy during chemical reactions in the human body, and the generation of heat and light in firework explosions. In summary, exothermic reactions are characterized by the release of energy to the surroundings. The enthalpy of the products is less than that of the reactants, resulting in a negative change in enthalpy (∆H). On a potential energy diagram, the potential energy decreases from the reactants to the products, indicating the energy released during the reaction. Understanding exothermic reactions helps us comprehend processes that release energy, such as combustion, respiration, and various natural phenomena.

< Back Group 17 ​ ​ Previous Next 🔬 Chapter 11: Group 17 🔬 Halogens and Their Compounds 🧫: Halogens such as chlorine, bromine, and iodine exist as covalent diatomic molecules. They are oxidizing agents, with fluorine being the strongest and iodine the weakest. Chlorine reacts with cold hydroxide ions in a disproportionation reaction to produce commercial bleach. Chlorine has various industrial uses, including the manufacture of PVC and halogenated hydrocarbons used as solvents, refrigerants, and in aerosols. Chlorination of water with chlorine is important for the prevention of diseases.

< Back Electrochemistry ​ ​ Previous Next 🔬 Chapter 7: Redox Reactions 🔬 Learning Outcomes 🎯: Calculate oxidation numbers of elements in compounds and ions. Describe and explain redox processes in terms of electron transfer and changes in oxidation number. Use changes in oxidation numbers to help balance chemical equations. What is a Redox Reaction? 🔄: Oxidation is the gain of oxygen by an element or the loss of electrons. Reduction is the loss of oxygen or the gain of electrons. Redox reactions involve both oxidation and reduction processes. Oxidation and reduction always take place together in redox reactions. Redox reactions are crucial in various natural processes such as photosynthesis and respiration. Oxidation Numbers and Electron Transfer ⚖️: Oxidation numbers can be used to determine whether a substance has been oxidized or reduced during a chemical reaction. An increase in oxidation number indicates oxidation, while a decrease indicates reduction. Redox reactions can also be explained in terms of electron loss (oxidation) or electron gain (reduction). Balancing Redox Reactions 🧮: Half-equations can be used to represent the oxidation and reduction processes separately. Balancing redox reactions involves ensuring that the number of electrons lost in the oxidation process is equal to the number of electrons gained in the reduction process. Examples of Redox Reactions 🧪: The reaction between magnesium and oxygen to form magnesium oxide is an example of a redox reaction. The reaction between sodium and chlorine to form sodium chloride involves the transfer of electrons and is also a redox reaction. Rusting is an oxidation reaction that involves the reaction of iron with oxygen in the presence of water.

< Back Nitrogen and sulfur ​ ​ Previous Next 🔬 Chapter 13: Nitrogen and Sulfur 🔬 Learning Outcomes 🎯: Describe and explain the lack of reactivity of nitrogen gas, the basicity of ammonia, and the formation and structure of the ammonium ion. State the industrial importance of ammonia and nitrogen compounds derived from ammonia. State and explain the environmental consequences of the uncontrolled use of nitrate fertilizers. Describe the natural and man-made occurrences of oxides of nitrogen and their catalytic removal from exhaust gases of internal combustion engines. Describe the formation of sulfur dioxide gas from sulfur-contaminated fossil fuel, its role in the formation of acid rain, and how acid rain affects the environment. Nitrogen and Its Compounds 🌬️: Nitrogen gas is relatively unreactive due to the triple bond between nitrogen atoms in N2 molecules. Ammonia is a basic compound that forms the ammonium ion when it reacts with acids. Ammonia and its derivatives are industrially important, especially in the production of fertilizers. Environmental Impact of Nitrogen Compounds 🌍: The excessive use of nitrate fertilizers can lead to environmental problems such as water pollution and eutrophication. Oxides of nitrogen are pollutants that can be produced naturally or by human activities, such as combustion in engines. They play a role in the formation of acid rain. Sulfur Dioxide and Acid Rain ☔: Sulfur dioxide is produced when sulfur-containing fossil fuels are burned. It is a major contributor to acid rain, which can have harmful effects on the environment, including soil, water, and buildings.