How Well Do You Know Your Thermal Analyis & Calorimetry Facts?

1. What is represented on the following picture?

The first multi-function cooking robot ever invented

The first calorimeter ever invented

The first artificial earth satellite ever sent to space

Some dada artwork from early 20th century

The picture represents the first calorimeter ever invented.

Explanation

The picture represents the first calorimeter ever invented.

2. DSC section DSC means Differential Scanning Calorimetry. What is the advantage of a "differential" calorimeter?

It compensates from the heat effects linked with sample holders

It reduces the calorimetric signal background noise

It makes a big difference…

It improves the calorimeter furnace temperature control

A "differential" calorimeter is advantageous because it compensates for the heat effects that are linked with sample holders. This means that any heat effects caused by the sample holders themselves are accounted for and eliminated, allowing for more accurate measurements of the sample's heat properties.

Explanation

A "differential" calorimeter is advantageous because it compensates for the heat effects that are linked with sample holders. This means that any heat effects caused by the sample holders themselves are accounted for and eliminated, allowing for more accurate measurements of the sample's heat properties.

3. Who discovered the thermo electric effect that is applied in thermocouples, widely used in most of the existing thermoanalyzers?

Thomas Edison (1847 – 1931)

Thomas Johann Seebeck (1770 – 1831)

Albert Einstein (1879 – 1955)

André-Marie Ampère (1775-1836)

Thomas Johann Seebeck is credited with discovering the thermo electric effect that is applied in thermocouples. Thermocouples are widely used in most thermoanalyzers.

Explanation

Thomas Johann Seebeck is credited with discovering the thermo electric effect that is applied in thermocouples. Thermocouples are widely used in most thermoanalyzers.

4. What is the meaning of the term "accuracy"?

Accuracy relates the agreement between the measured concentration and the « true » value

The nearness of a result or the mean of a set of results to the true value

All of the above, they are definitions of accuracy from different sources

The given answer is correct because it states that all of the options provided are definitions of accuracy from different sources. This suggests that accuracy can be understood as the agreement between the measured concentration and the true value, the differences between the mean of a set of results or an individual result and the accepted true or correct value, and the nearness of a result or the mean of a set of results to the true value. These definitions highlight the concept of accuracy in various contexts and perspectives.

Explanation

The given answer is correct because it states that all of the options provided are definitions of accuracy from different sources. This suggests that accuracy can be understood as the agreement between the measured concentration and the true value, the differences between the mean of a set of results or an individual result and the accepted true or correct value, and the nearness of a result or the mean of a set of results to the true value. These definitions highlight the concept of accuracy in various contexts and perspectives.

5. How did Antoine Lavoisier, co-inventor of the first experimental calorimeter, end his life?

He had a heart attack while “staying” at his mistress’s place

He died accidentally during the explosion of an uncontrolled combustion experimental set-up

He was branded a traitor by French Revolutionists and executed by Guillotine

He joined the French Revolutionists side and died during the Storming of the Bastille

Antoine Lavoisier, co-inventor of the first experimental calorimeter, was branded a traitor by French Revolutionists and executed by Guillotine.

Explanation

Antoine Lavoisier, co-inventor of the first experimental calorimeter, was branded a traitor by French Revolutionists and executed by Guillotine.

6. What coupled technique would be the best fit to study the desorption of the following gases from a zeolithe?

Carbon dioxide (C02)
Ammonia (NH3)
Nitrogen dioxide (N02)
Nitrous oxide (N20)

TGA-DSC

TGA-MS

TGA-YMCA

TGA-FTIR

TGA-MS (Thermogravimetric Analysis-Mass Spectrometry) would be the best fit coupled technique to study the desorption of the given gases from a zeolite. TGA measures the weight loss of the sample as a function of temperature, while MS analyzes the mass and structure of the desorbed gases. This combination allows for the identification and quantification of the gases released during desorption, providing valuable information about their behavior and interaction with the zeolite.

Explanation

TGA-MS (Thermogravimetric Analysis-Mass Spectrometry) would be the best fit coupled technique to study the desorption of the given gases from a zeolite. TGA measures the weight loss of the sample as a function of temperature, while MS analyzes the mass and structure of the desorbed gases. This combination allows for the identification and quantification of the gases released during desorption, providing valuable information about their behavior and interaction with the zeolite.

7. The DSC thermogram below corresponds to the heating of a cocoa butter sample under air after a first melting and consecutive fast cooling to -10°C. How to interpret the successive endothermic, exothermic, and endothermic peaks?

The tested sample contains impurities that melt, then form a solid solution in the main compound, which melts quickly afterwards

First cooling caused the formation of a metastable form that melts, immediately crystallizes into thermodynamically stable form, that quickly melts

During melting, cocoa butter overflowed the crucible, and was spilled on the DSC sensor, leading to an odd signal

The correct answer suggests that the successive endothermic, exothermic, and endothermic peaks in the DSC thermogram are a result of the first cooling causing the formation of a metastable form of the cocoa butter sample. This metastable form then quickly melts, crystallizes into a thermodynamically stable form, and quickly melts again. This interpretation explains the observed peaks and the sequence of events during the heating process.

Explanation

The correct answer suggests that the successive endothermic, exothermic, and endothermic peaks in the DSC thermogram are a result of the first cooling causing the formation of a metastable form of the cocoa butter sample. This metastable form then quickly melts, crystallizes into a thermodynamically stable form, and quickly melts again. This interpretation explains the observed peaks and the sequence of events during the heating process.

8. What is the particularity of these calorimeters?

The one on the right side supported the Dutch team at the 2010 FIFA Soccer World Cup in South Africa

The one on the left side grew old and had to be equipped with a wheeled walker

They survived from fire in a lab

They were designed after some dada artwork from early 20th century

The particularity of these calorimeters is that they survived from a fire in a lab.

Explanation

The particularity of these calorimeters is that they survived from a fire in a lab.

9. Who developed the DSC technique?

E.S. Watson and M.J. O'Neill in 1960

A. Tian and E. Calvet in 1947

S. Thelma and G. Louise in 1991

G. Wolf and J. Lechner in 1985

E.S. Watson and M.J. O'Neill developed the DSC technique in 1960.

Explanation

E.S. Watson and M.J. O'Neill developed the DSC technique in 1960.

10. Thermal analysis techniques measure a parameter as a function of time and temperature. TGA measures sample weight, DSC measures heatflow … What does a Sievert's instrument measure?

The radiations emitted by a sample

The sievertness of the sample

The volume of a sample

The pressure drop linked to gas sorption on a sample

A Sievert's instrument measures the radiations emitted by a sample.

Explanation

A Sievert's instrument measures the radiations emitted by a sample.

11. Among the calorimetry measurement principles that are represented below, which one corresponds to the Calvet principle?

A

B

C

D

The Calvet principle corresponds to option C.

Explanation

The Calvet principle corresponds to option C.

12. What is the mistake in the following DSC protocol?

There is not enough hexane to record its critical point

There will be an overpressure due to hexane vapour pressure and it will explode

Hexane will react with oxygen from air, decompose, produce gases, and the crucible will explode

Nothing will happen with hexane on that temperature range, so this experiment is pointless

The mistake in the given DSC protocol is that there will be an overpressure due to hexane vapor pressure, resulting in an explosion. This is a safety hazard as the high pressure can cause damage and harm.

Explanation

The mistake in the given DSC protocol is that there will be an overpressure due to hexane vapor pressure, resulting in an explosion. This is a safety hazard as the high pressure can cause damage and harm.

13. How could I improve the separation of the following three exothermic peaks?

By increasing the temperature scanning rate and increasing the sample mass

By decreasing the temperature scanning rate and increasing the sample mass

By increasing the temperature scanning rate and decreasing the sample mass

By decreasing the temperature scanning rate and decreasing the sample mass

not-available-via-ai

Explanation

not-available-via-ai

14. TGA section Buoyancy effect A well known source of error in TGA is linked with buoyancy effect: when the temperature of the gas surrounding the sample changes, its density changes and the amplitude of the sample buoyancy force changes. As a consequence, the TGA system records a fake mass uptake (drift). What other effect, mainly observed at high temperatures, is also a source of TGA baseline drift ?

Change of viscosity of the gas

Change of thermal conductivity of the gas

Change of density of the sample

Climate change

At high temperatures, the viscosity of the gas can change, which can cause TGA baseline drift. This is because the change in viscosity affects the flow of the gas, leading to variations in the heat transfer and mass transfer within the TGA system. As a result, the recorded mass uptake may be inaccurate due to this drift caused by the change in gas viscosity.

Explanation

At high temperatures, the viscosity of the gas can change, which can cause TGA baseline drift. This is because the change in viscosity affects the flow of the gas, leading to variations in the heat transfer and mass transfer within the TGA system. As a result, the recorded mass uptake may be inaccurate due to this drift caused by the change in gas viscosity.

15. Among the thermodynamic systems described below, which corresponds to the isoperibolic one?

TE is constant and TS is variable

TE = TS

TE is variable and TS is constant

TE = T0 + βmt + AT.sin (w.t)

The isoperibolic thermodynamic system is characterized by a constant temperature of the surroundings (TE) and a variable temperature of the system (TS). In this system, the energy exchange between the system and the surroundings occurs at a constant temperature. This is different from the other options where either both TE and TS are constant, or both TE and TS are variable.

Explanation

The isoperibolic thermodynamic system is characterized by a constant temperature of the surroundings (TE) and a variable temperature of the system (TS). In this system, the energy exchange between the system and the surroundings occurs at a constant temperature. This is different from the other options where either both TE and TS are constant, or both TE and TS are variable.

16. General section The specific heat of water at 15°C is 4.18J.g^-1.K^-1. What is the specific heat of water at 15°C in Btu.pound^-1.°F^-1 ?

1 Btu.pound-1.°F-1

2.89 Btu.pound-1.°F-1

8.31 Btu.pound-1.°F-1

Who cares? Btu, pounds, and °F aren’t international system units!

The specific heat of water at 15°C is 4.18J.g-1.K-1. To convert this to Btu.pound-1.°F-1, we need to use conversion factors. 1J = 0.000947817 Btu, 1g = 0.00220462 pound, and 1K = 1.8°F. By multiplying these conversion factors with the given specific heat, we can find that the specific heat of water at 15°C is 1 Btu.pound-1.°F-1.

Explanation

The specific heat of water at 15°C is 4.18J.g-1.K-1. To convert this to Btu.pound-1.°F-1, we need to use conversion factors. 1J = 0.000947817 Btu, 1g = 0.00220462 pound, and 1K = 1.8°F. By multiplying these conversion factors with the given specific heat, we can find that the specific heat of water at 15°C is 1 Btu.pound-1.°F-1.

17. There is a mistake in the following protocol. What will happen? The sample is heated to 1100°C under inert atmosphere, then is switched to air. Tempearature is kept at 1100°C during a 24 hours oxydation isotherm.

Platinum suspensions will oxidize at the same time than the SiC samples

SiC will never oxidize

Platinum will melt and the sample will fall at the bottom of the furnace

Silicium will form an eutectic with platinum, melt, and fall in the furnace bottom

When the sample is heated to 1100°C under an inert atmosphere and then switched to air, the presence of silicon (silicium) and platinum can lead to the formation of a eutectic mixture. This eutectic mixture will have a lower melting point than both silicon and platinum individually. As a result, the eutectic mixture will melt, causing the sample to fall to the bottom of the furnace.

Explanation

When the sample is heated to 1100°C under an inert atmosphere and then switched to air, the presence of silicon (silicium) and platinum can lead to the formation of a eutectic mixture. This eutectic mixture will have a lower melting point than both silicon and platinum individually. As a result, the eutectic mixture will melt, causing the sample to fall to the bottom of the furnace.

18. In the following glass transition determination thermogram, the signal deviates a lot, potentially leading to an error in the Tg determination. Approximately how much alumina should be placed in the reference crucible to shift the baseline to 0mW and thus improve the signal deviation? Heating rate: 10 K/min Heat capacity of alumina at 50°C: 0.83J.g^-1.K^-1

2 mg

10 mg

100 mg

200 mg

The signal deviation in the thermogram can potentially lead to an error in determining the glass transition temperature (Tg). To improve the signal deviation, the baseline needs to be shifted to 0mW. This can be achieved by adding alumina to the reference crucible. The amount of alumina needed to shift the baseline to 0mW is approximately 200 mg.

Explanation

The signal deviation in the thermogram can potentially lead to an error in determining the glass transition temperature (Tg). To improve the signal deviation, the baseline needs to be shifted to 0mW. This can be achieved by adding alumina to the reference crucible. The amount of alumina needed to shift the baseline to 0mW is approximately 200 mg.

19. What is represented on the following picture?

The first multi-function cooking robot ever invented

The first calorimeter ever invented

The first artificial earth satellite ever sent to space

Some dada artwork from early 20th century

The picture represents the first multi-function cooking robot ever invented.

Explanation

The picture represents the first multi-function cooking robot ever invented.

20. How many water molecules per metal sulphate (MeSO₄) molecule are lost by the sample in the tested temperature range? In other words, what is the value of x in the reaction below?

½

1

2

4

In the reaction, MeSO4 is a metal sulphate compound. The question asks how many water molecules are lost per MeSO4 molecule in the tested temperature range. The answer is ½, which means that for each MeSO4 molecule, only half of a water molecule is lost.

Explanation

In the reaction, MeSO4 is a metal sulphate compound. The question asks how many water molecules are lost per MeSO4 molecule in the tested temperature range. The answer is ½, which means that for each MeSO4 molecule, only half of a water molecule is lost.