Dry ice is
Ice cube
Sodium chloride
Liquid nitrogen
Solid carbon dioxide
On a hot day, placing a cup full of ice water on the table heats up as cup of hot tea on the same table cools down. write the reason.
Two different liquids of same mass are kept in two identical vessels, which are placed in a freezer that extracts heat from them at the same rate causing each liquid to transform into a solid. The schematic figure below shows that temperature $T$ versus time $t$ plot for the two materials. We denote the specific heat of materials in the liquid (solid) states to be $C_{L 1}$ $\left(C_{S 1}\right)$ and $C_{L 2}\left(C_{S 2}\right)$, respectively. Choose the correct option given below.
A thermally insulted vessel contains $150\, g$ of water at $0\,^oC$. Then the air from the vessel is pumped out a adiabatically. A fraction of water turns into ice and the rest evaporates at $0\,^oC$ itself. The mass of evaporated water will be closes to ....... $g$ (Latent heat of vaporization of water $= 2.10 \times10^6\, Jkg^{-1}$ and Laten heat of Fusion of water $ = 3.36 \times10^5\,Jkg^{-1}$ )
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 ?
Write a latent heat unit and dimensional formula. On what does the value of latent heat depend ?