ASTM D2766-95(2009)
(Test Method)Standard Test Method for Specific Heat of Liquids and Solids (Withdrawn 2018)
Standard Test Method for Specific Heat of Liquids and Solids (Withdrawn 2018)
SIGNIFICANCE AND USE
The specific heat or heat capacity of a substance is a thermodynamic property that is a measure of the amount of energy required to produce a given temperature change within a unit quantity of that substance. It is used in engineering calculations that relate to the manner in which a given system may react to thermal stresses.
SCOPE
1.1 This test method covers the determination of the heat capacity of liquids and solids. It is applicable to liquids and solids that are chemically compatible with stainless steel, that have a vapor pressure less than 13.3 kPa (100 torr), and that do not undergo phase transformation throughout the range of test temperatures. The specific heat of materials with higher vapor pressures can be determined if their vapor pressures are known throughout the range of test temperatures.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
WITHDRAWN RATIONALE
This test method covers the determination of the heat capacity of liquids and solids. It is applicable to liquids and solids that are chemically compatible with stainless steel, that have a vapor pressure less than 13.3 kPa (100 torr), and that do not undergo phase transformation throughout the range of test temperatures. The specific heat of materials with higher vapor pressures can be determined if their vapor pressures are known throughout the range of test temperatures.
Formerly under the jurisdiction of Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, this test method was withdrawn in January 2018 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D2766 −95 (Reapproved 2009)
Standard Test Method for
Specific Heat of Liquids and Solids
This standard is issued under the fixed designation D2766; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
T = temperature of hot zone, °C,
f
T = initial temperature of calorimeter, °C,
1.1 This test method covers the determination of the heat c
T' = T − T =temperature differential, °C,
f c
capacity of liquids and solids. It is applicable to liquids and
R = resistance of nominal 1-Ω standard resistor,
solids that are chemically compatible with stainless steel, that
R = resistance of nominal 100-Ω standard resistor,
haveavaporpressurelessthan13.3kPa(100torr),andthatdo
R = resistance of nominal 10 000-Ω standard resistor,
10 000
not undergo phase transformation throughout the range of test
E = emf across nominal 1-Ω standard resistor,
temperatures. The specific heat of materials with higher vapor
E = emf across nominal 100-Ω standard resistor,
pressurescanbedeterminediftheirvaporpressuresareknown
E = emf across nominal 10 000-Ω standard resistor,
10 000
throughout the range of test temperatures.
t = timeofapplicationofcalibrationheatercurrent,s,
c
q = total heat developed by calibration heater, cal,
1.2 The values stated in SI units are to be regarded as the
∆E = total heat effect for container, mV,
c
standard. The values given in parentheses are for information
∆E = total heat effect for sample+container, mV,
s
only.
∆e = total heat effect for calibration of calorimeter
c
1.3 This standard does not purport to address all of the
system during container run, mV,
safety concerns, if any, associated with its use. It is the
∆e = total heat effect for calibration of calorimeter
s
responsibility of the user of this standard to establish appro-
system during sample run, mV,
priate safety and health practices and determine the applica-
∆H = totalenthalpychangeforcontainerchangingfrom
c
bility of regulatory limitations prior to use.
T to T ,
f c
∆H = total enthalpy change for sample plus container
T
2. Referenced Documents
changing from T to T ,
f c
∆H = totalenthalpychangeforsamplechangingfromT
2.1 ASTM Standards:
s f
D1217Test Method for Density and Relative Density (Spe- to T ,
c
F = calorimeter factor,
cific Gravity) of Liquids by Bingham Pycnometer
W = weight of sample corrected for air buoyancy
3. Terminology d = density of sample at T,
f f
d = density of sample at T ,
c c
3.1 Definitions of Terms Specific to This Standard:
V = total volume of sample container,
T
3.1.1 specific heat—the ratio of the amount of heat needed
V = volume of sample vapor at T,
f f
to raise the temperature of a mass of the substance by a
V = volume of sample vapor at T ,
c c
specified amount to that required to raise the temperature of an
P = vapor pressure of sample at T,
f f
equal mass of water by the same amount, assuming no phase
P = vapor pressure of sample at T ,
c c
change in either case.
N = moles sample vapor at T,
f f
N = moles sample vapor at T ,
3.2 Symbols: c c
N = moles sample vapor condensed,
∆H = heat of vaporization of sample,
v
This test method is under jurisdiction ofASTM Committee D02 on Petroleum R = gas constant, and
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
K = heat of vaporization correction.
mittee D02.L0.07 on Engineering Sciences of High Performance Fluids and Solids
3.3 Units:
(Formally D02.1100).
Current edition approved Oct. 1, 2009. Published November 2009. Originally
3.3.1 The energy and thermal (heat) capacity units used in
approved in 1968. Last previous edition approved in 2005 as D2766–95(2005).
this method are defined as follows:
DOI: 10.1520/D2766-95R09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1 cal (International Table)=4.1868 J
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
1 Btu (British thermal unit, International Table)=
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 1055.06 J
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2766−95 (2009)
1 Btu/lb °F=1 cal/g °C
1 Btu/lb °F=4.1868 J/g K
3.3.2 For all but the most precise measurements made with
this method the rounded-off value of 4.19 J/cal can be used as
this is adequate for the precision of the test and avoids the
difficulty caused by the dual definition of the calorie.
4. Summary of Test Method
4.1 The enthalpy change,∆H , that occurs when an empty
c
sample container is transferred from a hot zone of constant
temperature to an adiabatic calorimeter at a fixed initial
temperature is measured for selected hot zone temperatures
evenly spread over the temperature range of interest.
4.2 Theenthalpychange,∆H ,thatoccurswhenacontainer
T
filled with the test specimen is transferred from a hot zone of
constant temperature, T , to an adiabatic calorimeter at a fixed
c
initial temperature is measured for selected hot-zone tempera-
tures evenly spread over the temperature range of interest.
4.3 The net enthalpy change per gram of sample is then
expressed as an analytical power function of the temperature
differential T'. The first derivative of this function with respect
to the actual temperature, T, yields the specific heat of the
f
sample as a function of temperature. Actual values of the
specific heat may be obtained from solutions of this equation
which is valid over the same range of temperatures over which
the total enthalpy changes,∆H , were measured.
T
5. Significance and Use
5.1 The specific heat or heat capacity of a substance is a
thermodynamic property that is a measure of the amount of
energy required to produce a given temperature change within
a unit quantity of that substance. It is used in engineering
calculations that relate to the manner in which a given system
may react to thermal stresses.
6. Apparatus
FIG. 1 Specific Heat Apparatus
6.1 Drop-Method-of-Mixtures Calorimeter, consisting es-
sentially of a vertically mounted, thermostatically controlled,
tube furnace and a water-filled adiabatic calorimeter. The
for the purpose of measuring the temperature of the capsule
furnace is mounted with respect to the calorimeter in such a
while in the tube furnace. See Fig. 3.
way that it may be swung from a remote position to a location
3,4
directlyoverthecalorimeterandreturnedrapidlytotheremote 6.4 Resistor, 1-Ω precision type.
position. The sample container may thus be dropped directly 3,4
6.5 Resistor, 100-Ω precision type.
into the calorimeter with a minimum transfer of radiation from
3,4
6.6 Resistor, 10 000-Ω precision type.
furnace to calorimeter. Details of construction are shown in
Fig. 1. 6.7 Amplifier, zero centered range, linear response with
preset ranges to include 625 µV, 6100 µV, 6200 µV,
6.2 Sample Container—A stainless steel sample container
6500µV, 61000 µV, and 62000 µV; with error not to exceed
with a polytetrafluoroethylene seal suitable for use at tempera-
60.04%ofoutput;withzerodriftafterwarm-upnottoexceed
tures up to 533 K (500°F) is shown in Fig. 2.
60.5 µV offset within which drift will not exceed 60.2
6.3 Potential Measuring Devices (two required), potential
measuring device capable of measurement of up to 1 V with a
−6
precision of 10 V or a potentiometer assembly with sensitiv-
If you are aware of alternative suppliers, please provide this information to
ASTM International Headquarters. Your comments will receive careful consider-
ity of at least 1 µV or a digital multimeter with equivalent
ation at a meeting of the responsible technical committee, which you may attend.
sensitivity, range, and a minimum of six digit resolution is
The sole source of supply of the apparatus known to the committee at this time
acceptable. A direct reading digital temperature indicating
isModels9330/1,9330/100,9330/10K,GuildlineInstruments,Inc.,103Commerce
device may be substituted for the potential measuring device St., Ste 160, Lake Mary, FL 32795-2590.
D2766−95 (2009)
time. The measured value of∆H as a function of temperature
c
serves a dual purpose: (1) it provides the value of container
enthalpy change that must be deducted from∆H to determine
T
∆H;(2) simultaneously it affords a correction term that
S
cancels out the effect of conduction and radiation that occur
during sample transfer.
7.2 The following procedure is used to determine ∆H at
c
each selected temperature for each sample container over the
temperaturerangeofinterest(Note3):Bringtheemptysample
containertoaconstanttemperatureintheverticaltubefurnace.
Monitor its temperature with the copper-constantan thermo-
couple that is fitted into the center well of the container.While
the container is equilibrating, adjust the temperature of the
calorimeter by cooling or warming it as required to bring it to
atemperaturejustbelowtheselectedinitialstartingpoint(Note
FIG. 2 Specific Heat Sample Cell
4).Adjust the thermistor bridge so that it will have zero output
at the selected initial temperature. Any changes of this bridge
setting will require recalibration of the system. The amplified
µV/min. Equivalent instrumentation with different fixed poten-
output of the thermistor bridge is displayed on the recorder
tial ranges is acceptable provided the same overall potential
(Note 5). As the calorimeter approaches the selected starting
ranges are covered.
temperature, the output of the bridge becomes less negative
6.8 Strip Chart Recorder, with nominal 25 cm chart, 65
and approaches zero (the starting temperature). Just before the
mV, zero center.
output reaches zero, determine the temperature of the capsule
6.9 Binding Posts,lowthermalemf-type,withprovisionfor
byreadingtheoutputofthecopper-constantanthermocoupleto
guard circuit.
the nearest 1 µV (Note 6). At the moment the calorimeter
temperature passes through the selected starting temperature,
6.10 Rotary Switch, low thermal emf-type, with provision
swing the vertical furnace over the calorimeter and drop the
for guard circuit.
sample container into the calorimeter. Return the furnace
3,5
6.11 Thermistor Bridge.
immediately to its rest position. As the calorimeter warms,
3,5
6.12 Thermistor.
adjustthepotentiometerbiastobringtherecordedtemperature
traceonscale.Recordthetemperatureuntilitresumesanearly
6.13 Thermocouple, copper-constantan, stainless steel
3,6
linear drift. Then determine the total heat effect, measured in
sheath, 3.2 mm ( ⁄8 in.) in outside diameter.
millivolts, by taking the algebraic sum of the initial and final
6.14 Power Supply, 24 V dc.
potentiometer biases and the extrapolated differences in the
NOTE 1—Two 12 V automobile batteries in series have proved
temperature traces (Note 7). In order to determine the exact
satisfactory as a power supply. They should be new and fully charged.
energy equivalent of the millivolt change measured during the
3,7
6.15 Power Supply, constant-voltage, for potentiometer. drop of the container, it is necessary to perform a heater run.
This run is made after every drop as the calibration of the
6.16 Standard Cell, unsaturated cadmium type, for potenti-
,8 system is a function of the size of the heat effect as well as of
ometer.
the water content of the calorimeter. Since the rate of energy
input from the electrical heater is of necessity much smaller
7. Calibration
than that encountered in the drop itself, it is not possible to
7.1 The enthalpy change,∆H , that occurs when an empty
c
duplicate the heat effect of the drop exactly. Instead, adjust the
sample container is transferred from the tube furnace at a fixed
temperature of the calorimeter so that the bias of the potenti-
temperatureintotheadiabaticcalorimeterisnotafunctiononly
ometer is such that an electrical heat effect of known size will
of the composition of the container and the temperature
occur over a range intermediate between the initial and final
difference between the furnace and the calorimeter. Because
points of the drop (Note 8). During the heater run, measure the
heatlossesoccurastheresultsofbothconductionandradiation
current through the heater and the potential drop across the
from the container during the transfer process, some heat is
heaterbymonitoringthepotentialsacrossstandardresistors R
also transferred by radiation to the calorimeter at the same
and R . Measure the time interval of application of heat to
the nearest 0.1 s, and determine the change in potential due to
The sole source of supply of the apparatus known to the committee at this time
the electrical heat effect by taking the algebraic sum of the
is VWR, Welch Div., Chicago, IL, under the following catalog number: Thermistor
initial and final potentiometer biases and the extrapolated
Bridge—No. S-81601; Thermistor—No. S-81620.
initial and final temperatures.
The sole source of supply of the apparatus known to the committee at this time
is Thermocouple Products Co., Inc., Villa Park, IL.
NOTE 2—If organic materials are to be studied, it is suggested that
The sole source of supply of the apparatus known to the committee at this time
fifteen determinations of ∆H made at roughly equal intervals over the
is No. 245G-NW-19, Instrulab, Inc., Dayton, OH.
c
The sole source of supply of the apparatus known to the committee at this time temperature range from 311 to 533 K (100 to 500°F) will suffice in most
is Eppley Laboratory, Inc., Newport, RI. instances.
D2766−95 (2009)
FIG. 3 Specific Heat Measuring and Control Circuit Diagram
NOTE3—Theinitialtemperatureisusuallyselectedtobeslightlylower insignificant even if fairly large (for example, up to 0.5 mV) deviations
thanaverageroomtemperaturesothatcalorimeterdriftduetostirringand from the midpoint are allowed.
deviations from complete adiabaticity will result in a slow, almost linear
7.3 Repeat the procedure described in 7.2 for each tempera-
drift through the selected starting temperature.
tureatwhichitisdesiredtocalibrateagivensamplecontainer.
NOTE 4—Normally a 50 µV full-scale setting of the amplifier is used
and initial potentiometer bias is set at zero.
8. Procedure
NOTE 5—Provided that an accurate calibration of the thermocouple is
madepriortoitsuse,itshouldbepossibletodeterminethetemperatureto
8.1 Fill the sample container with a weighed amount of the
the nearest 0.1°C with accuracy.
sample. Make appropriat
...
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