Recent questions in Chemical Thermodynamics

Devitrification of glass is a process for which change in entropy, $\Delta S$ is

asked Feb 28, 2014 by mosymeow_1

1 answer

Dissolution of gases in water is

asked Feb 28, 2014 by mosymeow_1

2 answers

Two coins eash weighing 10 g are heated to 473 K and dropped into two identical vessels A and B, each containing 500 g of water at 298 K. The coin dropped in vessel A is made up of aluminium and the coin dropped into vessel B is amde up of silver. The rise in temperature of water in container

asked Feb 27, 2014 by mosymeow_1

1 answer

At $298\; K, 0.1\; mol$ of methane is burnt in a bomb calorimeter such that $\Delta V=0$ . The heat so produced is taken up by a large amount of water so that $\Delta T$ is very small.

asked Feb 27, 2014 by mosymeow_1

1 answer

A $1.0\; g$ sample of substance A at $100^\circ C$ is added to $100\; mL$ of $H_2O$ at $25^\circ C$ . Using separate $100\; mL$ portions of $H_2O$ , the procedure is repeated with substance $B$ and then with substance $C$ . How will the final temperatures of the water compare?

asked Feb 27, 2014 by mosymeow_1

1 answer

The amount of heat evloved when 500 $cm^3$ 0.1 M HCl is mixed with 200 $cm^3$ of 0.2 M NaOH is

asked Feb 27, 2014 by mosymeow_1

1 answer

$H_2O(g) + C(s) \rightarrow CO(g) + H_2(g)$ ; $\Delta H = 131$ kJ. $CO(g) + \frac{1}{2} O_2(g) \rightarrow CO_2(g)$ ; $\Delta H = -282$ kJ. $H_2(g) + \frac{1}{2} O_2(g) \rightarrow H_2O(g)$ ; $\Delta H = -242$ kJ. $C(s) + O_2(g) \rightarrow CO_2(g)$ ; $\Delta H = X$ kJ. Based on the above thermochemical equations find the value of X.

asked Feb 27, 2014 by mosymeow_1

1 answer

10 moles of an ideal gas expands into vacuum. The work done is

asked Feb 27, 2014 by mosymeow_1

2 answers

The source of energy in a cellular reaction is

asked Feb 27, 2014 by mosymeow_1

2 answers

The heat liberated when $1.89\; g$ of benzoic acid is burnt in a bomb calorimeter at $25^\circ C$ increases the temperature of $18.94\; kg$ of water by $0.632^\circ C$ . If the specific heat of water at $25^\circ C$ is $0.998 \;cal/g$ deg, the value of the heat of combustion of benzoic acid is

asked Feb 27, 2014 by mosymeow_1

1 answer

What is the P-P bond energy in kJ/mol, if the heat of atomisation of $PH_3(g)$ and $P_2H_4(g)$ are 954 kJ/mol and 1485 kJ/mol, respectively?

asked Feb 27, 2014 by mosymeow_1

1 answer

Let the activation energies of two reactions be $E_1$ and $E_2$ where $E_1>E_2$ . If temperature of the system is increased from $T_1$ to $T_2$ , the rate constant of the reactions changes from $k_1$ to $k_1'$ in the first reaction and from $k_2$ to $k_2'$ in the second reaction. Which of the following expression is correct?

asked Feb 27, 2014 by mosymeow_1

1 answer

Which one of the following equation is true? (Given, $\delta E = T\delta S -P\delta V$ and $H=E+PV$ )

asked Feb 27, 2014 by mosymeow_1

1 answer

The reaction $A \leftrightharpoons B$ ; $\Delta H = +24\; kJ/mol$ . For the reaction $B\leftrightharpoons C$ ; $\Delta H=-18$ kJ/mol. The decreasing order of enthalpy of $A, B$ and $C$ follow the order

asked Feb 27, 2014 by mosymeow_1

1 answer

The enthalpy of neutralisation of oxalic acid by strong base is 25.4 kcal/mol. The enthalpy of neutralisation of strong acid and strong base is -13.7 kcal/equil. The enthalpy of dissociation of $H_2C_2O_4 \leftrightharpoons 2H^+ + C_2O_4^{2-}$ is

asked Feb 27, 2014 by mosymeow_1

1 answer

Cooking is fast in a pressure cooker because

asked Feb 27, 2014 by mosymeow_1

2 answers

To raise the temperature of 4.48 litres of an ideal gas at STP by $15^\circ C$ it requires 12.0 calories. The $C_P$ of the gas is

asked Feb 27, 2014 by mosymeow_1

1 answer

How many calories are required to heat 40 grams of argon from $40-100^\circ C$ at constant volume? (R = 2 cal/mol K)

asked Feb 27, 2014 by mosymeow_1

1 answer

$\Delta G^\circ$ for a reaction is 46.06 kcal/mol, $K_P$ for the reaction at 300 K is

asked Feb 27, 2014 by mosymeow_1

1 answer

Enthalpy =

asked Feb 27, 2014 by mosymeow_1

2 answers

Given, the enthalpy of combustion of glucose is 3000 kJ/mol. How much of glucose one has to consume to walk a distance of 5 km, provided 150 kJ of energy is needed for muscular work to walk a distance of 1 km and only 30 % energy is available for muscular work?

asked Feb 27, 2014 by mosymeow_1

1 answer

When 0.1 mole of a gas absorbs 41.75 J of heat, the rise in temperature occurs equal to $20 ^\circ C$ . The gas must be

asked Feb 27, 2014 by mosymeow_1

1 answer

Enthalpy of formation of (C=C) and (C-C) in $C_2H_4$ is -590 kJ/mol and -331 kJ/mol, respectively. What is the enthalpy change when ethylene polymerises to form polythene?

asked Feb 27, 2014 by mosymeow_1

1 answer

At 273 K the enthalpy of a certain reaction is -20.75 kJ. If heat capacities of the reactants and products are the same, then what will be the enthalpy of the same reaction at 373 K?

asked Feb 27, 2014 by mosymeow_1

1 answer

$CO(g) + \frac{1}{2} O _2 \longrightarrow CO_2$ , $\Delta H$ and $\Delta S$ for the reaction are $-283\; KJ$ and $-87\; JK^{-1}$ . It was intended to carry out this reaction at $1000, 1500, 3000$ and $3500\; K$ . At which of these temperatures would this reaction be thermodynamically spontaneous?

asked Feb 27, 2014 by mosymeow_1

1 answer

Some equations are given below. Which of the following processes does not correctly represent the first law of thermodynamics ?

asked Feb 27, 2014 by mosymeow_1

1 answer

To 100 $cm^3$ water at 298 K, 0.06 mole of $KNO_3$ is added. The enthalpy of $KNO_3$ (aq) solution is 35.8 kJ $mol^{-1}$ . What will be the temperature of the solution, after the solute is dissolved?

asked Feb 27, 2014 by mosymeow_1

1 answer

Study the given diagram. 3 moles of gas is put through a series of thermodynamic changes as shown graphically in a cyclic process. The processes A $\rightarrow$ B, B $\rightarrow$ C and C $\rightarrow$ A respectively are

asked Feb 27, 2014 by mosymeow_1

1 answer

Heat of neutralisation of HCl with $NH_4OH$ and NaOH with $CH_3COOH$ are respectively -51.4 and -50.6 kJ $eq^{-1}$ . What will be the heat of neutralisation of acetic acid with $NH_4OH$ ?

asked Feb 26, 2014 by mosymeow_1

1 answer

If the heat of neutralisation for a strong acid-base reaction is -57.1 kJ what would be the heat released when 350 $cm^3$ of 0.20 M $H_2SO_4$ is mixed with 650 $cm^3$ of $0.10\; M\; NaOH$ ?

asked Feb 26, 2014 by mosymeow_1

1 answer

If the bond dissociation energies of the diatomic molecules $XY, X_2$ and $Y_2$ are in the ratio of 1 : 1 : 0.5 and $\Delta_fH$ for the formation of XY is -200 kJ $mol^{-1}$ . What is the bond dissociation energy of $X_2$ will be

asked Feb 26, 2014 by mosymeow_1

1 answer

$N_2 + 3H_2 \longrightarrow 2NH_3$ This reaction is carried out at constant temperature and pressure. If $\Delta H$ and $\Delta U$ are enthalpy and internal energy change for the reaction, which of the following expression is true?

asked Feb 26, 2014 by mosymeow_1

1 answer

For a spontaneous reaction, the $\Delta G$ , equilibrium constant, K and $E^\circ _{cell}$ will be respectively

asked Feb 26, 2014 by mosymeow_1

1 answer

$MgO(s) + 2HCl(aq) \longrightarrow MgCl_2(aq) + H_2O(l)$ ; The absolute enthalpy of neutralisation of the reaction is

asked Feb 26, 2014 by mosymeow_1

1 answer

How much heat would release when an aqueous solution containing 0.5 mol of $HNO_3$ is mixed with 0.3 mol of $OH^{-1}$ ? Given, enthalpy of neutralisation is -57.1 kJ.

asked Feb 26, 2014 by mosymeow_1

1 answer

At 1 atm pressure, for a reaction $\Delta H = + 30.558$ kJ $mol^{-1}$ and $\Delta S = 0.066$ kJ $mol^{-1}$ . The temperature at which free energy is equal to zero and the nature of the reaction below this temperature are

asked Feb 26, 2014 by mosymeow_1

1 answer

Study the following table and, on the basis of these values of $\Delta H$ and $\Delta S$ for five different reactions, predict which one of these will be spontaneous at all temperatures?

asked Feb 26, 2014 by mosymeow_1

1 answer

A cylinder of gas is assumed to contain 14 kg of butane. A normal family requires 20,000 kJ of energy per day for cooking. How many days will the butane gas in the cylinder last?

asked Feb 26, 2014 by mosymeow_1

1 answer

What is the change in entropy of 1 mole of a perfect gas, which expands isothermally to ten times its original volume?

asked Feb 26, 2014 by mosymeow_1

1 answer

The heat liberated when 50 $cm^3$ of 0.2 N $H_2SO_4$ is mixed with 50 $cm^3$ of 1 N KOH, is

asked Feb 25, 2014 by mosymeow_1

1 answer

Show the relation between the enthalpies of the reactions: $H_2(g)+ \frac{1}{2} O_2(g) \rightarrow H_2O(g); \Delta H_1$ and $H_2(g)+\frac{1}{2}O_2(g) \rightarrow H_2O(l); \Delta H_2$

asked Feb 25, 2014 by mosymeow_1

1 answer

What is the standard Gibbs energy change for the reaction at 298 K, if standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are 382.64 kJ $mol^{-1}$ and -145.6 $JK^{-1}mol^{-1}$ , respectively.

asked Feb 25, 2014 by mosymeow_1

1 answer

How much heat is liberated when 100 mL of 1 N NaOH is neutralised by 300 mL of 1 N HCl ?

asked Feb 25, 2014 by mosymeow_1

1 answer

Keeping in mind the enthalpy of formation of HF and HCl i.e. -161 kJ and -92 kJ, respectively, which of the following statements do you think is incorrect?

asked Feb 25, 2014 by mosymeow_1

1 answer

The molar heat capacity of water at constant pressure, $C_P$ is $75JK^{-1}mol^{-1}$ . When 1.0 kJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is

asked Feb 25, 2014 by mosymeow_1

1 answer

Heat of combustion $\Delta H$ for $C(s), H_2(g)$ and $CH_4(g)$ are -94, -68 and -213 kcal/mol. Then $\Delta H$ for $C(s) + H_2(g) \rightarrow CH_4(g)$ is

asked Feb 25, 2014 by mosymeow_1

1 answer

Which of the following condition depicts a favourable condition for a spontaneous reaction?

asked Feb 25, 2014 by mosymeow_1

1 answer

Assume the enthalpy of combustion of methane and $CH_3OH$ are $x$ and $y$ respectively. If the enthalpy of $CH_4 + \frac{1}{2}O_2 \rightarrow CH_3OH$ is negative, then which relation is correct?

asked Feb 25, 2014 by mosymeow_1

1 answer

Given three reaction below, $N_2(g) + 3H_2(g) \leftrightharpoons 2NH_3(g); \Delta H_1$ , $H_1(g) + Cl_2(g) \leftrightharpoons 2HCl(g) ; \Delta H_2$ , $NH_3 (g) + 3Cl_2 \leftrightharpoons NCl_3(g) + 3HCl(g); -\Delta H_3$ . In the terms of $\Delta H_1, \Delta H_2$ and $\Delta H_3$ , heat of formation of $NCl_3(g)$ is

asked Feb 25, 2014 by mosymeow_1

1 answer

The following table lists the bond dissociation energy ( $E_{diss}$ ) for single covalent bonds formed between C and atoms A, B, D, E. Which of the atoms has smallest size?

asked Feb 25, 2014 by mosymeow_1

1 answer

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