Answer:
because strong heated makes temperatures and pressures reach the substance's triple point in its phase diagram, So the substance can be in a liquid case , and that is against the sublimation process meaning
which define as the transition of a matter or a substance from the solid phase to the gas phase directly, without passing through the intermediate liquid phase
sublimation process happens by absorbing of heat which makes molecules overcome attractive force between each other and changing to gas phase
but in the previous case it will pass through the liquid phase so it will not be sublimation process any more
Answer: There are five signs of chemical change
- Color Change
- Production of an odor
- Change of Temperature
- Evolution of Gas (bubbles start to form)
- Precipitate (starts to form a solid)
When these signs start to form you know chemical change is at work.
Hope this helps :)