Specific heat capacity joules

In the SI system, the unit of heat is taken as the same as that of mechanical energy and is therefore the Joule. For water at 298 K (the datum used for many definitions), the specific heat capacity Cp is 4186.8 J/kg K. 

Because inertial mass is involved in mechanical energy, the dimensions of all energy terms are M L2T 2. Inertial mass, however, is not involved in thermal energy (heat) and therefore specific heat capacity Cp has the dimensions MiL2T2/M//ff = MjM/ L2T 2 1 or according to whether energy is expressed in, joules or kilocalories, for... 

Specific heat capacity. Defined as the quantity of heat in joules required to raise the temperature of 1 kg of a substance by 1 °K. For gases, it is necessary to differentiate between specific heat capacity at constant pressure... 

The specific and molar heat capacities of some common substances are given in Table 6.1. Note that, although the values of the specific heat capacities are listed in joules per degree Celsius per gram (J-(°C) 1 -g 1), they could equally well be reported in joules per kelvin per gram (J-K 1-g ) with the same numerical values, because the size of the Celsius degree and the kelvin are the same. We can calculate the heat capacity of a substance from its mass and its specific heat capacity by rearranging the definition Cs = dm into C = mCs. Then we can use... 

A catalytic reaction must be performed in aqueous solution at industrial scale. The reaction is initiated by addition of catalyst at 40 °C. In order to evaluate the thermal risks, the reaction was performed at laboratory scale in a Dewar flask. The charge is 150 ml solution in a Dewar of 200 ml working volume. The volume and mass of catalyst can be ignored. For calibration of the Dewar by Joule effect, a heating resistor with a power of 40 W was used in 150ml water. The resistor was switched on for 15 minutes and the temperature increase was 40 K. During the reaction, the temperature increased from 40 to 90 °C within approximately 1.5 hours. The specific heat capacity of water is 4.2 kj kg K 1. 

Specific heat capacity joule per kilogram kelvin J/(kgK)... 

Heat capacity, molar Heat capacity at constant pressure Heat capacity at constant volume Helmholtz energy Internal energy Isothermal compressibility Joule-Thomson coefficient Pressure, osmotic Pressure coefficient Specific heat capacity Surface tension Temperature Celsius... 

Because heat, like work, is a form in which energy is transferred, the appropriate unit for it is also the joule. Historically, however, the connections among work, heat, and energy were not appreciated until the middle of the 19th century, by which time a separate unit for heat, the calorie, was already well established. One calorie was defined as the amount of heat required to increase the temperature of 1 g water from 14.5°C to 15.5°C (or, in other words, the specific heat capacity of water, Cg, at 15°C was defined as 1.00 cal g )-... 

Heat capacity can be expressed in joules or calories per mole per degree (molar heat capacity), or in joules or calories per gram per degree the latter is called the specific heat capacity or just the specific heat. 

Exactly three grams of carbon were burned to CO2 in a copper calorimeter. The mass of the calorimeter is 1 500 g, and the mass of water in the calorimeter is 2 000 g. The initial temperature was 20.0 °C and the final temperature 31.3 °C. Calculate the heat of combustion of carbon in joules per gram. Specific heat capacity of copper is 0.389 J/g - K. 

From the nowadays view, some of the ideas of Ostwald have been practiced, insofar as now the units are chosen in that way that they are coupled via the energy. For example, the thermal energy is defined in Joule, and the specific heat capacity has the unit Jkg K Similarly, the electric units are defined in the way that 1 V X 1 A X Is = IJ. 

P = absolute pressure T — absolute temperature V = specific volume p = density = 1/F S = specific entropy H = specific enthalpy U = specific internal energy Cp — specific heat capacity at constarit pressure C = specific heat capacity at constant volume C(T = specific heat capacity at constant saturation W = velocity of sound fx = Joule-Thomson coefficient R = universal gas constant... 

We need the specific heat capacity of iron and the conversion factor between joules and calories. 

Specific heat capacity, specific entropy joule per kilogram kelvin Jkg K ... 

The specific heat capacity of a material is the amount of heat energy (in joules) required to raise the temperature of unit mass (1kg) of the material by unit rise in temperature (1°C). 

The quantity of heat energy required to raise the temperature of a piece of materi depends upon the type of material and its mass. Thus equal masses of two different materials will require different amounts of heat energy to raise their temperature by the same amount e.g. 1 kg of water with a specific heat capacity of 4200J/(kg °C) will require 4200 joules of heat energy to raise its temperature by 1 C. Similarly, 1 kg of copper of specific heat capacity 386J/(kg °C) will require 386 joules to raise its temperature by 1°C. 

The SI unit of heat, as well as of work and energy is the joule, J as summarized in Fig. 2.3. Its dimension is expressed in [kg m s" ]. Heat and work describe the energy exchanged between thermodynamic systems, as discussed in Sect. 2.1.5 with the equation 6q -i- 8w = dU. An earlier, empirical unit, the calorie, was based on the specific heat capacity of water (1 calthemochemicai = 4.184 J). Since the early 2(f century, however, energy, heat, and work are more precisely determined in joules, making the calorie a superfluous unit. The calorie is not part of the SI units and should be abandoned. AU modem calorimetry is ultimately based on a comparison with heat generated by electrical work. 

The equilibrium description of melting and crystallisation is a subject of the field of thermodynamics. The basic quantity of calorimetry is the heat capacity, Cp (at constant pressure, in J moL ), which represents the amount of heat, Q (in joules, J), needed to be added to raise the temperature by 1 K or to be extracted to lower the temperature by 1 K for 1 mol of material. If the material analysed has a mass of 1 g, one calls this quantity the specific heat capacity, Cp (at constant pressure, in J K g ). In the more precise differential notation, one writes for the heat capacity that... 

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