$A$ closed bottle containing water at $30^{\circ}C$ is carried to the moon in a spaceship. If it is placed on the surface of the moon,what will happen to the water as soon as the lid is opened?

Which form of heat was believed in before the modern time?

It is possible for a substance to coexist in all three phases in equilibrium,when the substance is at

The top of a lake gets frozen at a place where the surrounding air is at a temperature of $-20\,^oC$. Then

$A$ block of ice at $-12^{\circ} C$ is slowly heated and converted into steam at $100^{\circ} C$. Which of the following curves best represents the event?

Answer the following questions based on the $P$ - $T$ phase diagram of carbon dioxide:
$(a)$ At what temperature and pressure can the solid,liquid and vapour phases of $CO_{2}$ co-exist in equilibrium?
$(b)$ What is the effect of decrease of pressure on the fusion and boiling point of $CO_{2}$?
$(c)$ What are the critical temperature and pressure for $CO_{2}$? What is their significance?
$(d)$ Is $CO_{2}$ solid,liquid or gas at $(i)$ $-70^{\circ}C$ under $1\;atm$,$(ii)$ $-60^{\circ}C$ under $10\;atm$,$(iii)$ $15^{\circ}C$ under $56\;atm$?