Search Results

Subscript Grade 10 SABIS SABIS The number used after a chemical symbol to indicate the number of atoms present per molecule

Each row in the periodic table is called a period while each column is called a group or family. Grade 10 SABIS

Sublimation The process of a substance changing directly from a solid to a gaseous state at a specific temperature.

Observations for the reaction of alkali metal with water: Grade 10 SABIS  Piece of metal floats (alkali metals have low density).  Piece of metal darts around.  A hissing sound is heard due to the evolution of a gas.  If red litmus paper is dipped in the solution, the paper turns blue due to the formation of the alkali metal hydroxide.  If few drops of phenolphthalein indicator are added to the water solution turns pink due to the formation of alkali metal hydroxide.  If the gas produced is tested with a lit splint, it burns with a squeaky pop sound.

Pressure The force applied per unit area.

Evaporation The process of a substance changing from a liquid to a gaseous state at a specific temperature.

Hess's Law Definition A Level Chemistry CIE Hess’s Law states that: This means that whether the reaction takes place in one or two steps, the total enthalpy change of the reaction will still be the same

Endothermic Grade 10 SABIS SABIS

6. The process of cooling liquid paradichlorobenzene until it Grade 10 SABIS SABIS

understand that chemical reactions are accompanied by enthalpy changes and these changes can be exothermic (ΔH is negative) or endothermic (ΔH is positive) A Level Chemistry CIE 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.

Endothermic Reaction Grade 10 SABIS SABIS Is a reaction which absorbs heat from the surrounding. As heat is absorbed, the temperature of the surrounding decreases. Decomposition reactions like electrolysis of water, heating a substance, melting, vaporization and sublimation are examples of endothermic processes

IGCSE CHEMISTRY 0620 TOPICS Read More Read More Read More Read More Read More Read More Read More Read More Read More Read More Read More Read More