CAS CH 131 Lecture Notes - Calorimetry, Naphthalene, Joule

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6 Feb 2014

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Heat qv is a direct measure of internal energy qv = ncv t. At constant pressure, u = qp-p v in liquids and gases, change is close to 0, so u = qp if u = qp, then qp = qv. Constant pressure calorimetry: heat for a non combustion reaction. 2: qsystem = qsolution + qcalorimeter + qreaction = 0 relate changes in heat to a chemical reaction, qreaction = -(qsolution + qcalorimeter, heat from system to surroundings or from surroundings to system them, ex. 100 ml of 0. 5 m naoh and 100 ml of 0. 5 m hcl in water create nacl and h2o. What is qreaction? d = 1 g/ml. calorimeter. 1. loss of heat ---- exothermic: 0. 1 l (0. 5 mol/l) = 0. 05 mol of h2o. 2. 81 kj/0. 05 mol = -56. 2 kj/mol for combustion reactions (a bomb is made) 1: qsystem = qwater + qbomb + qreaction = 0, ex. C10h8 (naphthalene) = 1. 435 g. ti = 20. 17oc.

Related Questions

Energy cannot be created nor destroyed, but it can be transferred between a reaction and its surroundings. The change in energy, Delta E, is positive if the reaction absorbs energy, and it is negative if the reaction releases energy. You may also see this expressed in terms of change in internal energy, Delta U. For the purposes of this question, Delta U and Delta E are equal. One way a reaction can transfer energy to or from the surroundings is by releasing or absorbing heat. A reaction can also transfer energy, in the form of work, through a change in volume. The total change in energy is the sum of the heat and work: Delta E = q + w At constant pressure, q = Delta H and w = -P Delta V and so Delta E = Delta H - P Delta V Assuming constant pressure, rank these reactions from most energy released by the system to most energy absorbed by the system, based on the following descriptions: Surroundings get colder and the system decreases in volume. Surroundings get hotter and the system expands in volume. Surroundings get hotter and the system decreases in volume. Surroundings get hotter and the system does not change in volume. Also assume that the magnitude of the volume and temperature changes are similar among the reactions. Rank from most energy released to most energy absorbed. To rank items as equivalent, overlap them. Energy cannot be created nor destroyed, but it can be transferred between a reaction and its surroundings. The change in energy, Delta E, is positive if the reaction absorbs energy, and it is negative if the reaction releases energy. You may also see this expressed in terms of change in internal energy, Delta U. For the purposes of this question, Delta U and Delta E are equal. One way a reaction can transfer energy to or from the surroundings is by releasing or absorbing heat. A reaction can also transfer energy, in the form of work, through a change in volume. The total change in energy is the sum of the heat and work: Delta E = q + w At constant pressure, q = Delta H and w = -P Delta V and so Delta E = Delta H - P Delta V A mole of X reacts at a constant pressure of 43.0 atm via the reaction X(g) + 4Y(g) - 2Z(g), Delta H degree = -75.0 kJ Before the reaction, the volume of the gaseous mixture was 5.00 L. After the reaction, the volume was 2.00 L Calculate the value of the total energy change. AE, in kilojoules. Express your answer with the appropriate units.

1 kg wet steam at 2 bar mixed with 2.3 kg steam at 6 bar T=200^oC by slow removal of partition from an insulted box. final p=4.5 bar

(Hint: Both chambers have same specific volume)

A) change internal energy for mixing (delta U)

B) internal energy of final state after mix (U_f)

C) whatâs temp (T_f) after mix is done? (Hint: vapor-liquid state region of pv)

D) Draw PV diagram and include all isotherms and states

E) replaced box with diathermal barrier, under constant Pressure, how much heat (Q) must be added/removed to final state after mixing to obtain a saturated liquid (x_Lapprox.=1)

CAS CH 131 Lecture Notes - Calorimetry, Naphthalene, Joule

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