A quantity of heat required to change the unit mass of a solid substance, from solid state to liquid state, while the temperature remains constant, is known as
Latent heat
Sublimation
Hoar frost
Latent heat of fusion
Answer the following questions based on the $P-T$ phase diagram of $CO _{2}$
$(a)\;CO _{2}$ at $1\; atm$ pressure and temperature $-60\,^{\circ} C$ is compressed isothermally. Does it go through a llquid phase?
$(b)$ What happens when $CO _{2}$ at $4\; atm$ pressure is cooled from room temperature at constant pressure?
$(c)$ Describe qualitatively the changes in a given mass of solid $CO _{2}$ at $10 \;atm$ pressure and temperature $-65\,^{\circ} C$ as it is heated up to room temperature at constant pressure.
$(d)\;CO_{2}$ is heated to a temperature $70\,^{\circ} C$ and compressed isothermally. What changes in its properties do you expect to observe?
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 sıgnificance ?
$(d)$ Is $CO _{2}$ solid, liquid or gas at $(a)\;-70\,^{\circ} C$ under $1\; atm$, $( b )\;-60\,^{\circ} C$ under $10 \;atm,$ $(c)$ $15\,^{\circ} C$ under $56$ atm ?
During constant temperature, we feel colder on a day when the relative humidity will be ....... $\%$
A child running a temperature of $101\,^{\circ} F$ is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to $98\,^{\circ} F$ in $20$ minutes, what is the average rate of extra evaporation caused, by the drug (in $g/min$). Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is $30\; kg$. The spectfic heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about $580\; cal \;g^{-1}$.
Why the cooking is faster in pressure cooker ?