Enthalpy of Solution

Q. the ratio of moles of water as water of crystallisation in LiCl and BaCl_2 i

Q. At absolute zero temperature, entropy of all substance is zero(True or False)

Q.

In certain chemical Reaction, $\Delta H=150KJ$ and $\Delta S=100J/K$ at $300K$. The value of $\Delta G$ would be

1. 300KJ

2. Zero

3. 330KJ

4. 120KJ

Q. 10 mL of a solution of NaCl containing KCI gave on evaporation 0.93 g of the mixed salt which gave 1.865 g of AgCl by reacting with AgNO, solution. Calculate the quantity of NaCl in10 mL of the solution.

Q. Which of the following is not the criteria of purity of a subs†an ce? (a) solubility (b) melting point (c) boiling point (d) density

Q. 36. 1.25 g of sample of limestone on heating gives 0.44 g carbon dioxide. The percentage purity of CaCO3 in limestone is

Q. Calculate the enthalpy of formation of $Mg{F}_2$ from the following data-
Enthalpy of sublimation for $Mg\left(s\right)\to Mg\left(g\right)=146.4kJmo{l}^{-1}$
Enthalpy of dissociation of $F_2\left(g\right)\to 2F\left(g\right)=155.8kJmo{l}^{-1}$
Ionisation energy of $Mg\left(g\right)\to M{g}^{2+}\left(g\right)=2186kJmo{l}^{-1}$
Electron gain enthalpy of $2F\to 2F^{-1}=2\times -322.6=-645.2kJmo{l}^{-1}$
Lattice enthalpy of $Mg{F}_2=-2922.5kJmo{l}^{-1}$

1. $-1079.5kJmo{l}^{-1}$
2. $1099.5kJmo{l}^{-1}$
3. $2200kJmo{l}^{-1}$
4. $2200kJmo{l}^{-1}$

Q. 0.54 g of organic compound give 1.5 g of Mg2P2O4. The percentage of P is

Q. one mole of anhydrous salt AB dissolves in water and liberates 15J/mol of heat .the value of △ H^° AB is -20.5 J/mol.hence the enthalpies of hydration of dissolution of hydrated salt AB .3H2O is

Q. Given are the bond enthalpies: ${ϵ}_{N\equiv N}=945{\text{kJ mol}}^{-1},{ϵ}_{H-H}=436{\text{kJ mol}}^{-1}$ and ${ϵ}_{(N-H)}=391{\text{kJ mol}}^{-1}$. The enthalpy change of the reaction
$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$ is

1. $-93{\text{kJ mol}}^{-1}$
2. $-89{\text{kJ mol}}^{-1}$
3. $-105{\text{kJ mol}}^{-1}$
4. $105{\text{kJ mol}}^{-1}$

Q. Is the percentage of water of crystallization in mgso4 .x H2O is 13% what is the value of x

Q.

Calculate the percentage composition of water of crystallisation in the following compounds -

I. FeSO_{4 .} 7H₂0

II. Na₂B₄O₇ . 10H₂O