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DNA can be modeled as an elastic rod that can be twisted or bent. Suppose a DNA molecule of length L is bent such that it lies on the arc of a circle of radius
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Thermodynamics, Statistical Thermodynamics, & Kinetics
- The enthalpy of combustion of diamond is -395.4 kJ/mol. C s, dia O2 g CO2 g Determine the fH of C s, dia.arrow_forwardA 1.00 mol sample of H2 is carefully warmed from 22 K to 40 K at constant volume. a What is the expected heat capacity of the hydrogen? b What is q for the process?arrow_forwardBenzoic acid of mass 1.35 g is reacted with oxygen in a constant volume calorimeter to form H20(1) and CO2(g) at 298 K. The mass of the water in the inner bath is 1.45 x 103 g. The temperature of the calorimeter and its contents rises 2.81 K as a result of this reaction. Part A Calculate the calorimeter constant. The standard enthalpy of combustion of benzoic acid at 298 K is –3227 kJ · mol-1. Cp.m (H2O,1) = 75.3 J· mol-1.K-1. Express your answer with the appropriate units. µA ? Ccal = Value Units Submit Request Answerarrow_forward
- The enthalpy of sublimation of calcium at 25 °c is 178.2 kJ mol- 1.How much energy (at constant temperature and pressure) must be supplied as heat to 5.0 g of solid calcium to produce a plasma (a gas of charged particles) composed of Ca2+ ions and electrons?arrow_forwardMeasurements show that the energy of a mixture of gaseous reactants increases by 261. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that – 175. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Round your answer to 3 kJ x10 significant digits. ? exothermic Is the reaction exothermic or endothermic? endothermicarrow_forwardThe variation of the Gibbs free energyof a given substance with temperature is given byG = aT + b + c/T. Determine how the entropy andenthalpy of this substance vary with temperature.arrow_forward
- Ethanol, C2H5OH, is brought to the boil at 1 atm. When an electric current of 0.682 A from a 12.0 V supply is passed for 500 s through a heating coil immersed in the boiling liquid, it is found that the temperature remains constant but 4.33 g of ethanol is vaporized. What is the enthalpy of vaporization of ethanol at its boiling point at 1 atm?arrow_forwardUse the molar bond enthalpy data in the table to estimate the value of AHxn for the equation NH, (g) + 20,(g) → HNO, (g) + H,O(g) The bonding in the molecules is shown. + H + O=O H.arrow_forwardA sample of 4.50 g of methane occupies 12.7 dm³ at 310 K. (a) Calculate the work done when the gas expands isothermally against a constant external pressure of 200 Torr until its volume has increased by 3.3 dm³. (b) Calculate the work that would be done if the same expansion occurred reversibly.arrow_forward
- Using a table of thermodynamic data, calculate ΔH rxn for 2SO(g) + 2/3 O_3(g) → 2SO_2(g)arrow_forwardA substance with a molar mass of 187.63 g mol−1 has the following thermochemical properties:cliquid = 2.483 J g−1 K−1 ΔfusH∘ = 4.876 kJ mol−1 csolid = 0.884 J g−1 K−1 ΔvapH∘ = 26.47 kJ mol−1 cgas = 0.346 J g−1 K−1 melting point = −23.47 ∘C normal boiling point = 152.64 ∘C What amount of heat, in kJ, should you remove from 78.436 g of the vapor at 200.00 ∘C to convert it to the solid at −30.00 ∘C?arrow_forwardA piece of zinc of mass 5.0 g is placed in a beaker of dilute hydrochloric acid. It undergoesthe reaction Zn + 2 H+ Zn + H2. Assuming that the volume of the reactant is negligible compared to the volume of the gas and that the gas is perfect, calculate the work done by the system as a result of the reaction. The atmospheric pressure is 1.1 atm and the temperature 23 °C.arrow_forward
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