Question:
Which of the following statements regarding the heat of reaction is/are CORRECT?
Which of the following statements regarding the heat of reaction is/are CORRECT?
Show Hint
Delta H is negative for exothermic and positive for endothermic reactions; heat of reaction is defined for complete stoichiometric conversion at the same T and P.
Updated On: Jul 17, 2026
- For endothermic reaction, it is positive.
- For exothermic reaction, it is negative.
- For exothermic reaction, it is positive.
- It is the enthalpy change for a process in which stoichiometric quantities of reactants, at a temperature and pressure, react completely in a single reaction to form products at the same temperature and pressure.
Show Solution
Verified By Collegedunia
The Correct Option is A, B, D
Solution and Explanation
Step 1: Recall the definition and sign convention.
Heat of reaction (delta H_rxn) at constant pressure is the enthalpy change when stoichiometric amounts of reactants react completely, in a single reaction, at the same T and P. Heat absorbed is positive, heat released is negative.
Step 2: Option A.
Endothermic reactions absorb heat, products end at higher enthalpy, delta H positive. TRUE.
Step 3: Option B.
Exothermic reactions release heat, products end at lower enthalpy, delta H negative. TRUE.
Step 4: Option C.
Contradicts B directly; exothermic is negative not positive. FALSE.
Step 5: Option D.
This is precisely the textbook definition of heat of reaction. TRUE.
Step 6: Conclusion.
A, B, D correct; C is the false statement. \[ \boxed{A, B, D} \]
Heat of reaction (delta H_rxn) at constant pressure is the enthalpy change when stoichiometric amounts of reactants react completely, in a single reaction, at the same T and P. Heat absorbed is positive, heat released is negative.
Step 2: Option A.
Endothermic reactions absorb heat, products end at higher enthalpy, delta H positive. TRUE.
Step 3: Option B.
Exothermic reactions release heat, products end at lower enthalpy, delta H negative. TRUE.
Step 4: Option C.
Contradicts B directly; exothermic is negative not positive. FALSE.
Step 5: Option D.
This is precisely the textbook definition of heat of reaction. TRUE.
Step 6: Conclusion.
A, B, D correct; C is the false statement. \[ \boxed{A, B, D} \]
Was this answer helpful?
0
0
Top GATE CH Process Calculations and Thermodynamics Questions
- Consider a vapour-liquid mixture of components A and B that obeys Raoult's law. The vapour pressure of A is half that of B. The vapour phase concentrations of A and B are 3 mol m\(^{-3}\) and 6 mol m\(^{-3}\), respectively. At equilibrium, the ratio of the liquid phase concentration of A to that of B is:
- Consider a binary mixture of components A and B at temperature \( T \) and pressure \( P \). Let \( \vec{V}_A \) and \( \vec{V}_B \) be the partial molar volumes of A and B, respectively. At a certain mole fraction of A, \( X_A \):
\[ \left( \frac{\partial \vec{V}_A}{\partial X_A} \right)_{T,P} = 22 \text{ cm}^3 \text{ mol}^{-1} \quad \text{and} \quad \left( \frac{\partial \vec{V}_B}{\partial X_A} \right)_{T,P} = -18 \text{ cm}^3 \text{ mol}^{-1} \]
The value of \( X_A \), rounded off to 2 decimal places, is ____. - The Newton-Raphson method is used to solve \( f(x) = 0 \), where \( f(x) = e^x - 5x \). Starting with an initial guess \( x^{(0)} = 1.0 \), the value of the next iterate \( x^{(1)} \), rounded off to 2 decimal places, is _____
- An isolated system consists of two perfectly sealed cuboidal compartments A and B separated by a movable rigid wall of cross-sectional area 0.1 m\(^2\) as shown in the figure. Initially, the movable wall is held in place by latches L1 and L2 such that the volume of compartment A is 0.1 m\(^3\). Compartment A contains a monoatomic ideal gas at 5 bar and 400 K. Compartment B is perfectly evacuated and contains a massless Hookean spring of force constant 0.3 N m\(^{-1}\) at its equilibrium length (stored elastic energy is zero). The latches L1 and L2 are released, the wall moves to the right by 0.2 m, where it is held at the new position by latches L3 and L4. Assume all the walls and latches are massless. The final equilibrium temperature of the gas in compartment A, in K, rounded off to 1 decimal place, is ______.
- Ethylene obeys the truncated virial equation-of-state \( \frac{PV}{RT} = 1 + \frac{BP}{RT} \) where \( P \) is the pressure, \( V \) is the molar volume, \( T \) is the absolute temperature, and \( B \) is the second virial coefficient. The universal gas constant \( R = 83.14 \) bar cm\(^3\) mol\(^{-1}\) K\(^{-1}\). At 340 K, the slope of the compressibility factor (\( Z \)) vs. pressure curve is \( -3.538 \times 10^{-3} \) bar\(^{-1}\). Let \( G_R \) denote the molar residual Gibbs free energy. At these conditions, the value of \( \left( \frac{\partial G_R}{\partial P} \right)_T \), in cm\(^3\) mol\(^{-1}\), rounded off to 1 decimal place, is _____.
View More Questions
Top GATE CH Questions
- Consider a Leniar Homogeneous system AX = 0, where A is N × N matrix and X is N × 1 vector. When we solve this 0 is null matrix of N × 1. Let R be the rank matrix for a for a Non-trivial solution.
- Which are true for Petroleum / Petrochemicals?
- F(x) = ex - 5x and the value of X0 = 1 then what will be the value of X1?
- The first non-zero term in the taylor series expansion of (1 - x) - e- x, about x = 0
- \(\frac{P}{Q}\) is not equal 1, \(\left(\frac{P}{Q}\right)^{\frac{P}{Q}} = P^{\frac{P}{Q} - 1}\)
View More Questions