Energetics
Bayani Gaba-gaba
Why does a hand warmer get hot? Why does a cold pack feel cold even though no ice is inside? The answers lie in energetics: the study of heat changes during chemical reactions. Some reactions release energy to the surroundings; others absorb it.
In this lesson you will learn to classify reactions as exothermic or endothermic, measure heat changes using calorimetry, draw energy level diagrams, and use bond energies to predict whether a reaction gives out or takes in heat. These calculations and diagrams are tested heavily across both Edexcel papers.
Manufura
- know that chemical reactions in which heat energy is given out are described as exothermic, and those in which heat energy is taken in are described as endothermic
- describe simple calorimetry experiments for reactions such as combustion, displacement, dissolving and neutralisation
- calculate the heat energy change from a measured temperature change using the expression Q = mcΔT
- calculate the molar enthalpy change (ΔH) from the heat energy change, Q
- draw and explain energy level diagrams to represent exothermic and endothermic reactions
- know that bond-breaking is an endothermic process and that bond-making is an exothermic process
- use bond energies to calculate the enthalpy change during a chemical reaction
- practical: investigate temperature changes accompanying some of the following types of change: - salts dissolving in water - neutralisation reactions - displacement reactions - combustion reactions.
Takardar Darasi
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Nazarin Darasi
Barka da kammala darasi akan Energetics. Yanzu da kuka bincika mahimman raayoyi da raayoyi, lokaci yayi da zaku gwada ilimin ku. Wannan sashe yana ba da ayyuka iri-iri Tambayoyin da aka tsara don ƙarfafa fahimtar ku da kuma taimaka muku auna fahimtar ku game da kayan.
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Yi wannan ɓangaren na kimantawa a matsayin wata dama don ƙarfafa fahimtarka kan batun kuma don gano duk wani yanki da kake buƙatar ƙarin karatu. Kada ka yanke ƙauna da duk wani ƙalubale da ka fuskanta; maimakon haka, ka kallesu a matsayin damar haɓaka da ingantawa.
- Which of the following is an endothermic process? A) Combustion of methane B) Neutralisation of acid and alkali C) Thermal decomposition of calcium carbonate D) Displacement of copper by iron Answer: C
- In an exothermic reaction, the energy level diagram shows: A) Products higher than reactants B) Products lower than reactants C) Products and reactants at the same level D) No activation energy Answer: B
- Bond breaking is always: A) Exothermic B) Endothermic C) Neutral D) Impossible to predict Answer: B
- The specific heat capacity of water is: A) 4.18 J g-1 K-1 B) 4.18 kJ g-1 K-1 C) 41.8 J g-1 K-1 D) 0.418 J g-1 K-1 Answer: A
- What does the activation energy represent on an energy level diagram? A) The total energy released B) The energy of the products C) The minimum energy needed to start the reaction D) The energy stored in the bonds Answer: C
Akwai a cikin manhajar Green Bridge
Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.
Akwai a cikin manhajar Green Bridge
Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.
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