AS Chemistry Revision-Chemistry for Life 1. Avagadro constant‚ 6.02 x 10²³ number of particles in 1 mole of a substance 2. Empirical formula-simplest ratio of atoms of each element in a compound 3. 4. Model of an atom Particle Mass on relative atomic scale Charge Proton 1 1+ Neutron 1 0 Electron Very small (0.00055) 1- 5. Radioactive isotopes Radiation What is it? Relative charge How does the nucleus change? Stopped by? Deflection in electric field? Alpha α Helium nuclei ⁴₂He +2 2 fewer
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exothermic B. is endothermic C. has H > 0 D. both a and c are correct E. both b and c are correct 4. Calculate the heat of vaporization of carbon tetrachloride given that the standard molar enthalpy of formation of liquid carbon tetrachloride is -135.4 kJ/mol and the standard molar enthalpy of formation of gaseous carbon tetrachloride is -102.9 kJ/mol. A. +102.9 kJ/mol B. -32.5 kJ/mol C. +238.2 kJ/mol D. +32.5 kJ/mol E. -238.2 kJ/mol 5. The complete combustion of 1 mole of propane
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Experiment I: Thermochemistry Background: Thermochemistry is the branch of chemistry that focuses on the studies of chemical reactions or physical changes and heat associated with chemical reactions. According to the first law of thermodynamics‚ energy cannot be created or destroyed but it can be converted from one form into another and/or transferred between different atoms‚ molecules‚ or substances. In general‚ energy can be classified into two categories: kinetic and potential. Kinetic energy
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answers 1. Define ΔHfθ and ΔHcθ ΔHfθ the enthalpy change when 1 mole of a compound is formed from its constituent elements in their standard states measured under standard conditions ΔHcθ the enthalpy change when 1 mole of a compound undergoes complete combustion measured under standard conditions 2. Write an equation for the enthalpy of formation of butane C4H10 4C(s) + 5H2(g) C4H10(g) 3. Write an equation for the enthalpy of combustion of butane C4H10 C4H10(g) +
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or absorption (endothermic reaction) of heat energy. When measured at constant pressure‚ the heat evolved (qp < 0) or absorbed (qp > 0) is equal to the enthalpy change‚ symbolized by ΔH. ΔH is positive for an endothermic process and negative for an exothermic one. If H f is the enthalpy of the final state and Hi of the initial state‚ the enthalpy change for a chemical reaction is given by Equation (1). ∆Hrxn = Hf - Hi (1) The process of measuring ΔH is called calorimetry. This involves “trapping”
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1. Physical Properties of Water and Ice 1. Molecular Weight: A. 18.01528 g/mol Water‚ Molar mass Triple Point The temperature and pressure at which solid‚ liquid‚ and gaseous water coexist in equilibrium is called the triple point of water. This point is used to define the units of temperature (the kelvin‚ the SI unit of thermodynamic temperature and‚ indirectly‚ the degree Celsius and even the degree Fahrenheit). As a consequence‚ water’s triple point temperature is a prescribed value rather
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compound to be used in hand warmer. Calorimetry experiment was conducted by dissolving three ionic compounds‚ CaCl2‚ Na2CO3‚ and NaCl‚ in distilled water to measure the enthalpy of solution.
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Hess’s law suggests that the enthalpy change of a reaction must be equal to the sum of the enthalpy changes of the related reactions which lead to the original reactions. The following are the reactions at the lab; 1) NaOH ( s) NaOH (aq) 2) NaOH (aq) + HCl (aq) NaCl (aq) + H2O (l) 3) NaOH (s) + HCl (aq) NaCl (aq) + H2O (l) As explained before‚ Hess’s Law states that the enthalpy change of reaction three (ΔH3) should be equal to the sum of the enthalpy changes of the first two reactions
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III Naminosuke Kubota Propellants and Explosives Thermochemical Aspects of Combustion Second‚ Completely Revised and Extended Edition IV The Author Prof. Dr. Naminosuke Kubota Asahi Kasei Chemicals Propellant Combustion Laboratory Arca East‚ Kinshi 3-2-1‚ Sumidaku Tokyo 130-6591‚ Japan All books published by Wiley-VCH are carefully produced. Nevertheless‚ authors‚ editors‚ and publisher do not warrant the information contained in these books‚ including this book‚ to be
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found forming in saline lakes‚ or one may find it in Boron‚ California. Historically‚ “the first Borax specimens came from several dry lake deposits in Tibet” (The Mineral Borax). This experiment was conducted to determine the standard entropy and enthalpy of the dissolving reaction of borax in water. The thermodynamic properties of the reaction helped to determine the change in heat and spontaneity within the system. Entropy is said to be the tendency for the universe to move towards disorder. If
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