A calorimeter is a device used for calorimetry, the science of measuring the heat of chemical reactions or physical changes as well as heat capacity. The word calorimeter is derived from the Latin word calor, meaning heat. Differential scanning calorimeters, isothermal microcalorimeters, titration calorimeters and accelerated rate calorimeters are among the most common types. A simple calorimeter just consists of a thermometer attached to an insulated container. To find the enthalpy change per mole of a substance X in a reaction between two liquids X and Y, they are added to the calorimeter and the initial and final (after the reaction has finished) temperatures are noted. Multiplying the temperature change by the mass and specific heat capacities of the liquids gives a value for the energy given off during the reaction (assuming the reaction was exothermic.). Dividing the energy change by how many moles of X were present gives its enthalpy change of reaction. This method is used primarily in academic teaching as it describes the theory of calorimetry. It doesn’t however account for the heat loss through the container or the heat capacity of the thermometer and container itself. In addition, the object placed inside the calorimeter show that the objects transferred their heat to the calorimeter and into the liquid, and the heat absorbed by the calorimeter and the liquid is equal to the heat given off by the metals. Image File history File linksMetadata No higher resolution available. ... An example of a reaction Calorimeter A reaction calorimeter is an instrument that enables the energy being released or absorbed by a reaction to be measured. ... The standard enthalpy change of reaction (denoted ΔH° or ΔHo)is the enthalpy change that occurs in a system when one mole of matter is transformed by a chemical reaction under standard conditions. ... An example of a reaction Calorimeter A reaction calorimeter is an instrument that enables the energy being released or absorbed by a reaction to be measured. ... The world’s first ice-calorimeter, used in the winter of 1782-83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat evolved in various chemical changes; calculations which were based on Joseph Black’s prior discovery of latent heat. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... For other uses, see Chemical reaction (disambiguation). ... A physical change involves the change just in the physical body of the substance without changing its composition. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... For other uses, see Latins and Latin (disambiguation). ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... For other uses, see Temperature (disambiguation). ... Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval. ...

Types

Reaction calorimeters

A reaction calorimeter is a calorimeter in which a chemical reaction is initiated within a closed insulated container. Reaction heats are measured and the total heat is obtained by integrating heatflow versus time. This is the standard used in industry to measure heats since industrial processes are engineered to run at constant temperatures. Reaction calorimetry can also be used to determine maximum heat release rate for chemical process engineering and for tracking the global kinetics of reactions. There are three common methods for measuring heat in reaction calorimeter: An example of a reaction Calorimeter A reaction calorimeter is an instrument that enables the energy being released or absorbed by a reaction to be measured. ... For other uses, see Chemical reaction (disambiguation). ...

Heat flow calorimetry

The cooling/heating jacket controls the temperature of the process. Heat is measured by monitoring the temperature difference between heat transfer fluid and the process fluid as follows:

Q = UA(T − t)

where

Q = process heating (or cooling) power (W)

U = overall heat transfer coefficient (W/(m²K))

A = heat transfer area (m²)

T = process temperature (K)

t = jacket temperature (K)

Heat flow calorimetry allows the user to measure heat whilst the process temperature remains under control. It is however a difficult technique to use and not particularly accurate. The value of U has to be predetermined by careful experimentation and any change in product composition, liquid level, process temperature, agitation rate or viscosity will upset the calibration.

A variation of the 'heat flow' technique is called 'power compensation' calorimetry. This method uses a cooling jacket operating at constant flow and temperature. The process temperature is regulated by adjusting the power of the electrical heater. When the experiment is started, the electrical heat and the cooling power (of the cooling jacket) are in balance. As the process heat load changes, the electrical power is varied in order to maintain the desired process temperature. The heat liberated or absorbed by the process is determined from the difference between the initial electrical power and the demand for electrical power at the time of measurement. The power compensation method is easier to set up than heat flow calorimetry but it suffers from the similar limitations since any change in product composition, liquid level, process temperature, agitation rate or viscosity will upset the calibration. The presence of an electrical heating element is also undesirable for process operations.

Heat balance calorimetry

The cooling/heating jacket controls the temperature of the process. Heat is measured by monitoring the heat gained or lost by the heat transfer fluid as follows:

Q = m_sC_ps(T_i − T_o)

where

Q = process heating (or cooling) power (W)

m_s = mass flow of heat transfer fluid (kg/s)

C_ps = specific heat of heat transfer fluid (J/(kg K))

T_i = inlet temperature of heat transfer fluid (K)

T_o = outlet temperature of heat transfer fluid (K)

Heat balance calorimetry is, in principle, the ideal method of measuring heat since the heat entering and leaving the system through the heating/cooling jacket is measured from the heat transfer fluid (which has known properties). This eliminates most of the calibration problems encountered by heat flow and power compensation calorimetry. Unfortunately, the method does not work well in traditional batch vessels since the process heat signal is obscured by large heat shifts in the cooling/heating jacket. A recent development in calorimetry however is that of constant flux cooling/heating jackets. These use variable geometry cooling jackets and can operate with cooling jackets at substantially constant temperature. These reaction calorimeters tend to be much simpler to use and are much more tolerant of changes in the process conditions (which would affect calibration in heat flow or power compensation calorimeters).

Bomb calorimeters

A bomb calorimeter is a type of calorimeter used in measuring the heat of combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure and force of the calorimeter as the reaction is being measured. Electrical energy is used to ignite the fuel, as the fuel is burning, it will heat up the surrounding air, which expands and escapes through a tube that leads the air out of the calorimeter. When the air is escaping through the copper tube it will also heat up the water outside the tube. The temperature of the water allows for calculating calorie content of the fuel.

In more recent calorimeter designs the whole bomb, pressurized with excess pure oxygen (typically at 20atm) and containing a known mass of fuel, is submerged under a known volume of water before the charge is (again electrically) ignited. The bomb, with fuel and oxygen, form a closed system - no air escapes during the reaction. The energy released by the combustion raises the temperature of the steel bomb, its contents, and the surrounding water jacket. The temperature change in the water is then accurately measured. This temperature rise, along with a bomb factor (which is dependent on the heat capacity of the metal bomb parts) is used to calculate the energy given out by the fuel burnt. A small correction is made to account for the electrical energy input and the burning fuse. After the temperature raise has been measured, the excess pressure in the bomb is released.

Constant-pressure calorimeter

A constant-pressure calorimeter measures the change in enthalpy of a reaction occurring in solution during which the atmospheric pressure remains constant. t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... Making a saline water solution by dissolving table salt (NaCl) in water This article is about chemical solutions. ... Atmospheric pressure is the pressure at any given point in the Earths atmosphere. ...

An example is a coffee-cup calorimeter, which is constructed from two nested Styrofoam cups and holes through which a thermometer and a stirring rod can be inserted. The inner cup holds the solution in which of the reaction occurs, and the outer cup provides insulation. Then Styrofoam is a trademark name for polystyrene thermal insulation material, manufactured by Dow Chemical Company. ... A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ...

Cp = (W * DH / (M * DT))

where

DH = Enthalpy of solution

DT = Change of temperature

W = weight of solute

M = molecular weight of solute

Differential scanning calorimeter

Main article: Differential scanning calorimeter

In a differential scanning calorimeter (DSC), heat flow into a sample—usually contained in a small aluminium capsule or 'pan'—is measured differentially, i.e., by comparing it to the flow into an empty reference pan. A differential scanning calorimeter is a scientific instrument that is used to observe the heat capacity of a sample as a function of temperature. ... This article is in the process of being merged into Heat, and may be outdated. ... Aluminum redirects here. ...

In a heat flux DSC, both pans sit on a small slab of material with a known (calibrated) heat resistance K. The temperature of the calorimeter is raised linearly with time (scanned), i.e., the heating rate dT/dt = β is kept constant. This time linearity requires good design and good (computerized) temperature control. Of course, controlled cooling and isothermal experiments are also possible.

Heat flows into the two pans by conduction. The flow of heat into the sample is larger because of its heat capacity C_p. The difference in flow dq/dt induces a small temperature difference ΔT across the slab. This temperature difference is measured using a thermocouple. The heat capacity can in principle be determined from this signal: To meet Wikipedias quality standards, this article or section may require cleanup. ... In electronics, thermocouples are a widely used type of temperature sensor and can also be used as a means to convert thermal potential difference into electric potential difference. ...

Note that this formula (equivalent to Newton's law of heat flow) is analogous to, and much older than, Ohm's law of electric flow: ΔV = R dQ/dt = R I. Heat flow along perfectly insulated wire Conduction is the transfer of heat or electric current from one substance to another by direct contact. ... This article is about the law related to electricity. ...

When suddenly heat is absorbed by the sample (e.g., when the sample melts), the signal will respond and exhibit a peak.

From the integral of this peak the enthalpy of melting can be determined, and from its onset the melting temperature. This article is about the concept of integrals in calculus. ...

Differential scanning calorimetry is a workhorse technique in many fields, particularly in polymer characterization. A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ...

A modulated temperature differential scanning calorimeter (MTDSC) is a type of DSC in which a small oscillation is imposed upon the otherwise linear heating rate.

This has a number of advantages. It facilitates the direct measurement of the heat capacity in one measurement, even in (quasi-)isothermal conditions. It permits the simultaneous measurement of heat effects that are reversible and not reversible at the timescale of the oscillation (reversing and non-reversing heat flow, respectively). It increases the sensitivity of the heat capacity measurement, allowing for scans at a slow underlying heating rate.

Isothermal titration calorimeter

Main article: Isothermal Titration Calorimetry

In an isothermal titration calorimeter, the heat of reaction is used to follow a titration experiment. This permits determination of the mid point (stoichiometry) (N) of a reaction as well as its enthalpy (delta H), entropy (delta S) and of primary concern the binding affinity (Ka) Isothermal Titration Calorimetry (ITC) is a biophysical technique used to determine the thermodynamic parameters of (biochemical) interactions. ... This article is about volumetric titration. ... Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry) is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemical equations). ...

The technique is gaining in importance particularly in the field of biochemistry, because it facilitates determination of substrate binding to enzymes. The technique is commonly used in the pharmaceutical industry to characterize potential drug candidates. Wöhler observes the synthesis of urea. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...

X-ray microcalorimeter

X ray microcalorimeter diagram

In 1982, a new approach to non-dispersive X-ray spectroscopy, based on the measurement of heat rather than charge, was proposed by Moseley et al. (1984). The detector, and X-ray microcalorimeter, works by sensing the heat pulses generated by X-ray photons when they are absorbed and thermalized. The temperature increase is directly proportional to photon energy. This invention combines high detector efficiency with high energy resolution, mainly achievable because of the low temperature of operation. Microcalorimeters have a low-heat-capacity mass that absorbs incident X-ray (UV, visible, or near IR) photons, a weak link to a low-temperature heat sink which provides the thermal isolation needed for a temperature rise to occur, and a thermometer to measure change in temperature. Following these ideas, a large development effort started. The first astronomical spacecraft that was designed, built and launched with embarqued cryogenic microcalorimeters was Astro-E2. NASA as well as ESA have plans for future missions (Constellation-X and XEUS, respectively) that will use some sort of micro-calorimeters. Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... X-ray spectroscopy is a gathering name for several spectroscopic techniques for determining the electronic structure of materials by using x-ray excitation. ... In physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field; for instance, light. ... This article is about the substance or device. ... The Astro-E2 satellite was a joint project between scientists from NASA and Japan Aerospace Exploration Agency (JAXA). ... For other uses, see NASA (disambiguation). ... This article is about the European Space Agency. ... Constellation-X, the Constellation X-ray Mission (formerly HTXS, the High Throughput X-ray Spectroscopy program) is a Next Generation X-ray Observatory dedicated to observations at high spectral resolution, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X-ray spectroscopy missions. ... XEUS is the X-ray Evolving Universe Spectroscopy space observatory that is being developed by the European Space Agency as a successor to the successful XMM-Newton X-ray satellite telescope. ...

Heat-loss calorimeter

Work in Progress - comments welcome

Cross-section view of a heat-loss calorimeter. The heat developed inside the cell is collected by the inner copper cup. Then, it flows through the silicone-rubber which serves as a thermal resistor and the outer copper cup, to the flowing water surrounding the outer copper cup.

Image File history File links No higher resolution available. ...

High-energy particle calorimeter

Main article: calorimeter (particle physics)

In particle physics, a calorimeter is a component of a detector that measures the energy of entering particles. In particle physics, a calorimeter is an experimental apparatus that measures the energy of particles. ... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... The Compact Muon Solenoid (CMS) is an example of a large particle detector. ... Helium atom (schematic) Showing two protons (red), two neutrons (green) and two electrons (yellow). ...

See also

• Enthalpy
• Heat
• Calorie
• Heat of combustion
• Calorimeter constant

t In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Etymology: French calorie, from Latin calor (heat), from calere (to be warm). ... It has been suggested that this article or section be merged with Heating value. ... There are very few or no other articles that link to this one. ... Brown glass jars with some clear lab glassware in the background Laboratory glassware refers to a variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratories. ... A beaker is a simple container for liquids, very commonly used in laboratories. ... A Büchner funnel connected to a flask with a tube leading to a vacuum pump Büchner funnel is a piece of laboratory equipment used in suction filtration. ... diagram of modern burette A burette (also buret) is a vertical cylindrical piece of laboratory glassware with a volumetric graduation on its full length and a precision tap, or stopcock, on the bottom. ... Cold fingers. ... Two different condensers are seen here: a Vigreux condenser is used as a fractionating column on left, and a Liebig condenser cools the hot vapors to liquid on right In a laboratory, a condenser is a piece of laboratory glassware used to cool hot vapors or liquids. ... A conical measure is a type of laboratory glassware which consists of a conical cup with a notch on the top to allow for the easy pouring of liquids. ... For other uses, see Crucible (disambiguation). ... This article is about a kind of glassware. ... A eudiometer is a device for measuring the change in volume of a gas mixture following combustion. ... A gas syringe showing its components separate and together A gas syringe also known as glass collecting bottle, is a piece of laboratory glassware used to draw a volume of a gas from a beaker or other closed system, or measure the volume of gas given off in a reaction. ... right|thumb|100px|Graduated cylinder. ... This article is about the laboratory instrument. ... Man looking at fungus inside of petri dishes A Petri dish is a shallow glass or plastic cylindrical dish that biologists use to culture microbes. ... The pycnometer or pyknometer is a device used for measuring fluid density, also known as a specific gravity bottle. ... Separating funnel A separating funnel or separation funnel or separatory funnel is a piece of equipment used in science to separate two immiscible liquids or solutions of different densities. ... A schematic representation of a Soxhlet extractor A Soxhlet extractor is a type of laboratory glassware invented in 1879 by Franz von Soxhlet. ... Caesium fluoride sample on a watch glass A watch glass is a circular, slightly concave piece of glass used in chemistry as a surface to evaporate a liquid, or as a cover for a beaker. ... Erlenmeyer flasks from the Argonne National Laboratory glassblowing shop. ... A Büchner funnel connected to a flask with a tube leading to a vacuum pump A Büchner flask, also known as a vacuum flask, is a thick-walled erlenmeyer flask with a glass tube and hose barb protruding about an inch from its neck, connected to an aspirator. ... Conical flask For the episode of The X-Files, see The Erlenmeyer Flask. ... (left to right) Erlenmeyer flask, Fleaker with upside down lid in front, Fleaker with lid on (all 300 mL), and Beaker (250 mL) A fleaker is a type of container for liquids used in the laboratory. ... Florence flask A Florence flask (also known as a round bottom flask or a boiling flask) is a piece of laboratory glassware. ... A beautiful retort. ... Round-bottom flasks are types of flasks having spherical bottoms used as laboratory glassware, mostly for chemical or biochemical work. ... An selection of Schlenk flasks and a Schlenk tube (bottom right) A Schlenk flask, or Schlenk tube is a reaction vessel typically used in air sensitive chemistry, invented by Wilhelm Schlenk. ... A volumetric flask. ... Glass Tube, a tube made of glass used for carrying gases between pieces of apparatus during a laboratory experiment. ... A large, thick-walled laboratory tube used for strongly heating substances with a Bunsen burner or other heat source. ... An NMR tube filled with a colorless sample, sealed with a green polyethylene cap and Parafilm Left to right: Flame, septum and polyethylene cap sealed NMR tubes Aqua regia has been added to these NMR tubes to remove all traces of organic material. ... A test tube (Sometimes culture tube) is a kind of laboratory glassware, composed of a fingerlike length of glass tubing, open at the top, sometimes with a rounded lip at the top, and a rounded U shaped bottom. ... The Thiele tube, named after the German chemist Johannes Thiele, is a laboratory glassware designed to contain and heat an oil bath. ... A thistle tube is a piece of laboratory glassware consisting mostly of a shaft of tube, with a reservoir and funnel-like section at the top. ... An agar plate streaked with microorganisms isolated from a deep-water sponge. ... A copper aspirator. ... Front loading autoclaves are common Stovetop autoclaves need to be monitored carefully and are the simplest of all autoclaves Multiple large autoclaves are used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal. ... Look up Bunsen burner in Wiktionary, the free dictionary. ... A chemostat. ... An electronic bacterial colony counter. ... A colorimeter is a device used to measure the absorbance of a specific solution. ... A laboratory tabletop centrifuge A laboratory centrifuge is a piece of laboratory equipment, driven by a motor, which spins liquid samples at high speed. ... A common modern fume hood. ... A glove compartment is a compartment built into the dashboard on the passengers side of an automobile, often used for miscellaneous storage. ... In microbiology, an incubator is a device for controlling the temperature, humidity, and other conditions in which a microbiological culture is being grown. ... A laboratory equipment for the homogenization of various types of material, such as tissue, plant, food, soil, and many others. ... UV light desinfects the sterile laminar flow cabinet when not in use Laminar flow cabinet or laminar flow closet is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive device. ... A magnetic stirrer is a type of laboratory equipment consisting of a rotating magnet or stationary electomagnets creating a rotating magnetic field. ... A microscope (Greek: (micron) = small + (skopein) = to look at) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... A 96-well microtiter plate. ... Plate readers (also know as microplate readers) are laboratory instruments designed to detect biological, chemical or physical events in samples stored in microtiter plates. ... Spectrophotometer In physics, spectrophotometry is the quantitative study of electromagnetic spectra. ... Three static mixers: The top is an alternating spiral with each spiral offset by 90°; the second is the above in a delivery tube, such as for epoxy; the last is a larger metal mixer used to divide a flow into streams that intersect at 90°. - Static Mixers use the... A stir bar (or flea) is a magnetic bar, used to stir a chemical reaction mixture or solution in a laboratory. ... A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... A Mini-Vortexer with micro-centrifuge tube. ...

External links

• Reaction Calorimeters
• Reaction Calorimeters for Lab and Process Development
• RTCal(TM): Calorimetry in Real-Time
• Omnical Reaction Microcalorimeters
• HEL Reaction Calorimetry

• Process Gas Calorimeter
• IKA - A leading manufacturer of Calorimeters