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1c7325d8-a76a-4025-8370-0699a1e77eae cheat sheet ap chemistry unit 3 https://k-chemistry.my.canva.site/ap-chemistry-unit-3-cheat-sheet-creation Summary

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).

fe176007-4e3a-46ed-b793-ee7a9cdf64c4 comparing physical and chemical changes Summary Physical Change Does not produce a new kind of matter Is generally easily reversible Is not accompanied by great heat change Does not produce an observable change in mass Chemical Change Always produces a new kind of matter Is generally not easily reversible Is usually accompanied by considerable heat change Produces an observable change in mass Some examples of physical changes include: Melting ice Boiling water Cutting paper Crushing a rock Mixing salt and water Some examples of chemical changes include: Burning wood Cooking food Rusting iron Digesting food Brewing beer

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08786cd6-efb7-4e90-aa4e-e2f751206045 Exothermic Summary A reaction that releases heat to the surroundings.

731c63f0-388c-4ddc-a8bc-30a23a39d0b8 Application on Hess’s Law medium Summary Question 1: Given the following reactions and their respective enthalpy changes: C(s) + O2(g) → CO2(g) ΔH1 = -393.5 kJ/mol H2(g) + 1/2O2(g) → H2O(l) ΔH2 = -286.0 kJ/mol C(s) + H2(g) → CH4(g) ΔH3 = -74.8 kJ/mol Calculate the enthalpy change for the reaction: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) Answer 1: To calculate the enthalpy change for the given reaction, we can use Hess's Law. By manipulating the given reactions, we can cancel out the common compounds and add the enthalpy changes. Multiplying reaction 1 by 2 gives: 2C(s) + 2O2(g) → 2CO2(g) 2ΔH1 = 2(-393.5 kJ/mol) = -787.0 kJ/mol Multiplying reaction 2 by 2 gives: 2H2(g) + O2(g) → 2H2O(l) 2ΔH2 = 2(-286.0 kJ/mol) = -572.0 kJ/mol Adding reactions 3, 2, and 1 gives: C(s) + H2(g) + 2H2(g) + O2(g) + 2O2(g) → CH4(g) + 2H2O(l) + 2CO2(g) ΔH3 + 2ΔH2 + 2ΔH1 = -74.8 kJ/mol + (-572.0 kJ/mol) + (-787.0 kJ/mol) = -1433.8 kJ/mol Since the given reaction is the reverse of the calculated reaction, the enthalpy change for the given reaction is the negative of the calculated value. ΔH = -(-1433.8 kJ/mol) = 1433.8 kJ/mol Question 2: Given the following reactions and their respective enthalpy changes: 2SO2(g) + O2(g) → 2SO3(g) ΔH1 = -198.2 kJ/mol S(s) + O2(g) → SO2(g) ΔH2 = -296.8 kJ/mol 2S(s) + 3O2(g) → 2SO3(g) ΔH3 = -792.0 kJ/mol Calculate the enthalpy change for the reaction: 2SO2(g) + O2(g) → 2SO3(g) + 198.2 kJ Answer 2: To calculate the enthalpy change for the given reaction, we can use Hess's Law. By manipulating the given reactions, we can cancel out the common compounds and add the enthalpy changes. Multiplying reaction 2 by 2 gives: 2S(s) + 2O2(g) → 2SO2(g) 2ΔH2 = 2(-296.8 kJ/mol) = -593.6 kJ/mol Adding reactions 1 and 2 gives: 2SO2(g) + O2(g) + 2S(s) + 2O2(g) → 2SO3(g) + 2

0081d36b-82f6-4a1c-bb1c-6494a4f26655 Atoms Summary The smallest unit of an element that retains the chemical properties of that element.

17c16aa0-7dde-4aaa-a1bc-a285ded5b1cd Amadeo Avogadro Summary Italian chemist Amadeo Avogadro (1776-1856) Avogadro , in full Lorenzo Romano Amedeo Carlo Avogadro, conte di Quaregna e Cerreto , (born August 9, 1776, Turin, in the Kingdom of Sardinia and Piedmont [Italy]—died July 9, 1856, Turin), Italian mathematical physicist who showed in what became known as Avogadro’s law that, under controlled conditions of temperature and pressure, equal volumes of gases contain an equal number of molecules.

b1864764-860a-4aa9-be5f-f4a80f31439b Molecules Summary The smallest unit of a compound that retains the chemical properties of that compound, made up of two or more atoms bonded together.

d00becc0-3d3b-44e6-8471-627397e2aeda Equation Summary A representation of a chemical reaction using the chemical formulas of the reactants and products.

47cbbfed-1427-4b03-a964-00cca42f0671 Atoms or ions that have the same electron arrangement around their nuclei as the noble gases will be stable. Summary

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