All Free Chemistry MCQs with Answers

• A. Loss of energy
• B. Gain of energy
• C. No energy change
• D. Sharing nucleus

Explanation: When chemical bonds are formed, energy is often released(lost).

• A. Heat
• B. Work
• C. Enthaply
• D. None of these

Explanation: Enthalpy (H) is a thermodynamic property that specifically represents the heat content of a system and it includes both the internal…

• A. Reversible reaction
• B. Endothermic reaction
• C. Exothermic reaction
• D. Oxidation reaction

Explanation: The decomposition of water into hydrogen and oxygen is an endothermic reaction : H2O →H2+1/2 O2 ∆H=+285.58 kJ/mol.

• A. Enthalpy of atomization
• B. Enthalpy of combustion
• C. Enthalpy of neutralization
• D. Enthalpy of sublimation

Explanation: The standard enthalpy of atomization of an element is defined as the amount of heat absorbed when one mole of gaseous atoms are formed…

• A. 15 kJ/mol
• B. -17kJ/mol
• C. 16.2 kJ/mol
• D. -16.5kJ/mol

Explanation: Enthalpy of solution (∆Hosol) of ammonium chloride is +16.2 kJmol-1.

• A. By spectrometry
• B. By conductometry
• C. By calorimetry
• D. By refractometry

Explanation: Calorimetry is a technique used to measure enthalpy changes associated with chemical reactions.

• A. Exothermic
• B. Spontaneous
• C. Endothermic
• D. Non-Spontaneous

Explanation: If enthalpy change is written in negative sign the reaction will be exothermic.

• A. KJ
• B. ∘F
• C. ∘C
• D. K

Explanation: The enthalpy change (ΔH) per mole is expressed in kilojoules per mole (kJ/mol).Kilojoules per mole (kJ/mol) are often used for convenience…

• A. Enthalpy
• B. Heat
• C. Temperature
• D. Pressure

Explanation: Heat is not a property of a system. It is therefore not a state function.

• A. Zero
• B. Less than 57 kJ mal-4
• C. 57KJ mol-1
• D. More than 57 kJ mol-1

Explanation: For weak acid and strong base titration, the heat of neutralization is lesser than the standard value 0f -57kJmol-1.

• A. Formation
• B. Atomization
• C. Neutralization
• D. Electron affinity

Explanation: Enthalpy of atomization is always positive.

• A. X + Y
• B. Y - X
• C. X - Y
• D. XY

Explanation: To find the heat of formation ΔH∘f of CO(g),we can use Hess's law,which states that the total enthalpy change for a reaction is…

• A. 57.0 kJ
• B. 28.5 kJ
• C. 11.4 kJ
• D. 34.9 kJ

Explanation: KOH is limiting reactant here so 0.2 moles of it react to give 11.4 kJ of energy

• A. Work done
• B. Internal energy
• C. Enthalpy
• D. State of system

Explanation: The amount of heat evolved or absorbed at constant volume is equal to change in internal energy of the system ∆E = qv.

• A. Translational energy only
• B. All kinds of K.E.
• C. Elastic potential energy only
• D. All of these

Explanation: The total of all the possible kinds of energies of the system is called its internal energy.

• A. 10 J
• B. -5 J
• C. -10 J
• D. +5 J

Explanation: W=PΔV ΔV= Change in volume = -0.03m3-0.05m3=-0.02m3 W=−(500Nm−2)×(−0.02m3)=10J Hence this option is incorrect.

• A. 12 J/mole
• B. 6 J/mole
• C. 3 J/mole
• D. 9 J/mole

Explanation: Explanation for this question will be added soon!

• A. 9 KJ/mol
• B. 27 KJ/mol
• C. 18 KJ/mol
• D. 36 KJ/mol

Explanation: The enthalpy change (ΔH) of a system is equal to the heat supplied (q) at constant pressure. In this case, ΔH=18 kJ/mol as q=18kJ/mol.

• A. Condensation of steam
• B. Haber's process for the manufacture of NH3
• C. Electrolysis of water
• D. Freezing of water

Explanation: The electrolysis of water is an endothermic process.

• A. Unity value
• B. Positive value
• C. Zero value
• D. Negative value

Explanation: Explanation for this question will be added soon!