Chemistry – ChemicalGeek.Com

Sample problems and solutions in Chemistry

Chemistry : Equilibrium constants, Enthalpy, Gibbs free energy, Arrhenius equation, rate constant, rate of reaction

Problem 1: Consider a gas phase reaction involving the synthesis of ammonia from hydrogen and nitrogen at 350 ^oC

$\dpi{120} \fn_cm \large N_{2} + 3H_{2}\rightarrow 2NH_{3}$

Starting with 1 mole of $\dpi{120} \fn_cm \large N_{2}$ and 3 moles of $\dpi{120} \fn_cm \large H_{2}$ , and no $\dpi{120} \fn_cm \large NH_{3}$ to start with, Find

An expression for the equilibrium constant $\dpi{120} \fn_cm \large K_{eq}$ in terms of the equilibrium conversion x
If the equilibrium conversion at 298K and 1 atm is 0.6, find the equilibrium constant $\dpi{120} \fn_cm \large K_{eq}$ for the above reaction at 298K and 1 atm.

Solution: $\dpi{120} \fn_cm \large K_{eq}$ = 16.33 Please contact via email for a detailed solution

Problem 2: For the gas phase reaction involving reactants X and Y, the individual heat capacities are 3 and 4 kcal/mol/K respectively while that of the products R and S are 6 and 7 kcal/mol/K respectively. Reactants X and Y react according to reaction below to form products P and Q at 227 ^oC and 5 atm . Find the heat of the reaction at 327 ^oC if the heat of the reaction at 227 ^oC is 100 kcal/mol.

$\dpi{120} \fn_cm \large X + 3Y\leftrightarrow 2R + 5S$

Solution: $\dpi{120} \fn_cm \large \Delta H(600)$ = 3700 kcal/mol. Please contact via email for a detailed solution

Problem 3: Isomerization of Catechol using hydrogen peroxide produces an equilibrium mixture of three isomers Catechol (ortho), Resorcinol (meta) and Hydroquinone (para) as represented by the scheme below

If the initial concentration of pure catechol is C_o , find the concentrations of the three isomers at equilibrium in terms of the given constants. Make suitable assumptions if required.

Solution: Please contact via email for a detailed solution

Problem 4: Pyrolysis (thermal cracking) of large chain hydrocarbon n-decane into smaller hydrocarbons at 627 ^oC was found to have an activation energy of 32.86 kJ/mol and reaction rate r . If the same reaction was carried out at 927 ^oC, the reaction rate was found to be mr . Find m to the closest positive integer possible.