There are following layers in earth atmosphere
a) Troposhere: the innermost layer or lowest part of atmosphere
b)stratosphere: next to troposhere
c)mesosphere:above stratosphere, here lowest temperature is observed
d)Thermosphere and Ionosphere: This layer allows long distance radio communication
e)Exosphere: this layer separates outer space from earth's surface.
The rules for naming an organic compound regarding punctuation are
a) a comma is put in between two digits (or numbers)
b) a digit and a letter are separated by a hyphan
Example:
3-ethyl-2-methylhexane
2,3,3-trimethylhexane
The answer would 5.66 x 10 power of 24
Explanation:
Sublimation is defined as a process in which solid state of a substance directly changes into vapor or gaseous state without undergoing liquid phase.
For example, naphthalene balls show sublimation at room temperature.
As this process does not cause any change in chemical composition of a substance. Hence, it is known as a physical process.
Similarly, when 
sublimes readily at 
. This shows change in physical state of carbon dioxide is taking place, i.e, from solid to gaseous phase.
Thus, we can conclude that when sublimes readily at then it means physical properties are usually associated with a compound that undergoes this kind of change.
Steel is an alloy and consists of more than one element (mainly iron and carbon), therefore steel is a mixture.
