Machine-translated by Google. Questions are authored in English.
Top

Discussion

In differential thermal analysis (DTA)

  • A.the temperature differences between the sample and reference are measured as a function of temperature
  • B.the differences in heat flow into the reference and sample are measured as a function of temperature
  • C.the change in the mass of the sample is measured as a function of temperature
  • D.the glass transition is observed as a sharp peak

Answer: A

In DTA, the temperature differences between the sample and reference are measured as a function of temperature.

Differential thermal analysis heats a sample and an inert reference together at a programmed rate and records the temperature difference between them. An endothermic event (melting, dehydration) makes the sample lag behind the reference and an exothermic one makes it run ahead, giving peaks in the difference.

Measuring the difference in heat flow into sample and reference is differential scanning calorimetry (DSC). Measuring the change in mass with temperature is thermogravimetric analysis (TGA). A glass transition is a change in heat capacity, so it shows as a step in the baseline, not as a sharp peak.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.