Newton 8 Flashcards
What is definition of temperature?
A measure of kinetic energy of molecular motion.
How to calculate kinetic energy?
What is sublimation?
It is the transition of a substance directly from the solid to the gas state, without passing through the liquid state.
What TGA stands for?
Thermo gravimetric analysis
What is TGA?
Analysis of the change in the mass of a sample on heating it. Measurements carried outt by a thermobalance.
What couses mass change in TGA?
Mass losses caused due to decomposition, sublimation and reactivity/desorption of products.
Mass gains due to oxidation.
Why atmosphere is controlled in TGA?
It protects against volatile or corrosive species, and it also prevents condensation of reaction products.
What DTA stands for?
Differential thermal analysis.
How DTA work?
In DTA the temperature of a sample is monitored with respect to a reference material while they are both being subjected to the same heating procedure.
What do we plot for DTA thermogram?
Temperature difference between sample and reference against temperature of the furnace.
What we see in DTA thermogram if we have endothermic reaction?
The T of the sample will lag behind thet of the reference and the minimum wil be observed on the DTA curve.
What does area under the DTA curve tells us?
Area is related to the enthalpy of the thermal event.
What we see in DTA thermogram if we have exoothermic reaction?
The T of the sample will be higher than reference and a maximum will be observed on the DTA curve
What does DSC stands for?
Differential scanning calorimetry
How does DSC works?
A sample and reference are maintained at the same temperature throughout the procedure by using separate power supplies. Any difference between the power supplied is recorded against the furnace temperature. Usualy temperature increases linearly as a function of time.
