Mass-specific heat capacity

This expression compares the characteristic time of runaway (TMRad) with the characteristic cooling time. Thus, knowing the mass, specific heat capacity, heat transfer coefficient, and heat exchange area allows the assessment. It is worth noting that, since the thermal time constant contains the ratio V/A, heat losses are proportional to the characteristic dimension of the container. 

The enthalpy of the wall can be expressed in terms of mass, specific heat capacity and the temperature of the wall... 

Where i ) is porosity, C is mass-specific heat capacity and p is density, and the index tof applies to total rock, mtx to solid rock matrix and por to pore filling fluid. 

There is a lot of misunderstanding over the effect of fillers on specific heat capacity. In fact, some of the notable books in the field give erroneous advice in this regard. The confusion comes from a failure to take into account the units of specific heat capacity. The units for mass-specific heat capacity are J kg K and values for mineral fillers are approximately three times greater than those for polymers. Therefore it is often stated that minerals reduce the specific heat capacity of polymers thus aiding polymer processing. However, like all other properties, one must consider the property on a volume basis and not a weight or mass basis. 

For state variables that may occur as intensive as well as extensive state variables, one should specify the nature of the variable to avoid confusion. If for example a specific heat capacity c is given it should always be made clear from units, indices or notation whether a mole-specific or a mass-specific heat capacity is considered. 

Specify what physical quantity should be multiplied by the mass-specific heat capacity to convert it into a mole-specific heat capacity ... 

Mole-specific heat capacity at constant volume is denoted c and mole-specific heat capacity at constant pressure is denoted Cp. Often, in technical calculations the so-called mass-specific heat capacity is used, defined by... 

The mass-specific heat capacity c of a substance is defined as the ratio between added heat 5Q per kg of substance and the temperature increment ... 

Mass-specific heat capacity at constant volume is denoted Cy and mass-specific heat capacity at constant pressure is denoted Cp. 

No standardized or incorporated list of symbols distinguishes between mole-specific and mass-specific heat capacity. In calculations, therefore, one should always specify by units or notation which kind of heat capacity is applied. 

In the present book the heat capacity of systems is always denoted C with the unit (J/K) mole-specific and mass-specific heat capacity are both denoted c with unit (J/molK) and (J/kgK), respectively. 

Problem. In an adiabatic calorimeter the temperatnre 0c in a sample of hardening concrete is measrued. The cement content C of the concrete is 350 kg/m. The concrete density q is 2350 kg/m and the mass-specific heat capacity Cp of the concrete is calculated as 1.10 kJ/kgK. The measurement shows the following relation between hardening time t and the adiabatic concrete temperatnre 0c... 

Conditions. In the calcnlations the mass-specific heat capacity of the concrete Cp is assumed to be constant at 1.10 kJ/kgK, independently of the degree of hardening. The measnrement is assnmed to be exactly adiabatic. 

In the table m, 0 and c denote the mass, temperatme and mass-specific heat capacity, respectively, of the constituent materials. With the given subscripts, the mass of sand is denoted m, temperatme of cement is denoted Oc, etc. 

Stainless steel is the designation for steel that has been made particularly corrosion proof by adding chromium Cr and nickel Ni. The table reference Engineering Materials Handbook specifies that austenitic stainless steel with 18 wt-% Cr and 8 wt-% Ni has a specific heat capacity c of 0.12 Btu/(°F lb). The unit 1 Btu ( British Thermal Unit ) = 1054 J and the unit 1 lb ( libra pound) = 0.454 kg. Calculate the mass-specific heat capacity c for the steel concerned using the SI unit kJ/kg K ... 

The thermal properties of a metal alloy is to be determined in a laboratory. Mea-sruements are made on a specimen of the metal with the mass m = 1050.0 g. The specimen is heated to the temperatrue 0 = 45.5 °C and then transferred to an adiabatic calorimeter containing 410 g water at a temperature of 18.2 °C. Any heat loss from the specimen during transfer to the calorimeter is disregarded. After temperature equihbrium has been reached in the calorimeter, a common temperature of 25.1 °C is measured for the water and the specimen. The heat capacity of the calorimeter and the water is C = 1.72 kJ/K. Calculate the heat capacity C (kJ/K) of the metal specimen and the mass-specific heat capacity c (kJ/kg K) of the metal ... 

A system consists of 5.00 kg of water in temperatnre equilibrium at 25.0 °C. A heat quantity of Q = 14630 J at constant pressure is added to the system from its surroundings so that the water temperature is increased to 25.7°C. Calculate the heat capacity of the system Cp (J/K), the mole-specific heat capacity of the water Cp (J/molK) and the mass-specific heat capacity Cp (J/kgK) of the water. The molar mass of H2O is 18.02 g/mol. 

Conditions. In the calculations the mass-specific heat capacity Cp of the concrete is estimated to be 1.10 kJ/kgK the density p of the concrete is estimated to be 2350... 

I Assume two adiabatic systems (a) and (b) each consisting of a steel block with the mass m = f.OOO kg. The mass-specific heat capacity of the steel is Cp = 0.481 kJ/kg K. In the initial state, the temperatures of the two blocks are 0a = 0°C and Of, = 100°C, respectively. At the time ti, the two steel blocks are brought into mutual thermal contact. At the time t2, the two blocks have reached thermal equilibrium at 0ab = 50°C. Calculate for the described process (1) — (2), the increase in entropy for the two subsystems ASa and ASf, respectively, as well as the increase in entropy AS at of the total system ... 

What is the total amount of heat that should be removed from the cross-section The total content of heat in the cross-section is proportional to the concrete volume considered for 1 m of the wall, this volume is proportional to the characteristic dimension S of the wall. The heat content per unit volume is qc, where q is the concrete density and c denotes the mass-specific heat capacity of the concrete. 

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