Chemistry ยท Physics
Thermodynamics and Chemical Kinetics
1,092 Questions
Thermodynamics and chemical kinetics are crucial branches of physical chemistry. This area focuses on energy transformations, reaction rates, equilibrium constants, and catalysts. These topics carry significant weight in competitive science and engineering examinations.
Enthalpy and energyChemical equilibriumEntropy conceptsReaction kinetics and catalysts
Thermodynamics and Chemical Kinetics Questions
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exothermic reaction
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endothermic reaction
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product
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reactant
A
Correct answer
Explanation
An exothermic reaction is defined as a chemical reaction that releases energy, usually in the form of heat, to its surroundings.
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combustion
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oxidation
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burning
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melting ice cubes
D
Correct answer
Explanation
Melting ice cubes requires an input of thermal energy to break the bonds of the solid structure, making it an endothermic process.
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light
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sound
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heat
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electric
C
Correct answer
Explanation
While energy can take many forms, the energy absorbed in most common endothermic chemical reactions is thermal energy (heat).
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exothermic reaction
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endothermic reaction
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a catalyst
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a reactant
B
Correct answer
Explanation
An endothermic reaction is a chemical process that requires a continuous input of energy from the surroundings to proceed.
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energy changes
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energy is released
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energy is stored
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energy is destroyed
A
Correct answer
Explanation
All chemical reactions involve the breaking and forming of bonds, which inherently requires or releases energy, leading to a change in the energy state of the system.
A
Correct answer
Explanation
Chemical reactions are categorized by their energy profile; some release energy (exothermic) while others absorb energy (endothermic).
A
Correct answer
Explanation
The law of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another.
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thermal energy
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mechanical energy
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chemical energy
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sound energy
C
Correct answer
Explanation
Chemical energy is stored in the bonds of chemical compounds and is released during chemical reactions, such as in batteries or burning fuel.
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The reaction is non-spontaneous
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The reaction cannot occur
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The reaction requires additional energy
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The reaction is spontaneous
D
Correct answer
Explanation
A negative change in Gibbs free energy (delta G < 0) indicates that a chemical reaction is exergonic and thermodynamically spontaneous, meaning it can occur without the input of additional energy.
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Transform into new substances.
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Change color, size and shape.
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React and group together differently.
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Don't react, don't change and don't move.
C
Correct answer
Explanation
In a chemical reaction, atoms are conserved but their chemical bonds are broken and formed, causing them to rearrange and group together differently to form new substances.
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makes heat
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consumes heat
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takes longer
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is shorter
B
Correct answer
Explanation
An endothermic reaction is a chemical reaction that absorbs heat energy from its surroundings. This absorption of heat typically causes the temperature of the immediate surroundings to drop. Exothermic reactions, by contrast, release heat into the surroundings.
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Transformed
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Given
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Taken
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Reflected
A
Correct answer
Explanation
The law of conservation of energy states that the total energy of an isolated system remains constant. Energy cannot be created or destroyed, but it can be transformed from one form, such as potential energy, to another, such as kinetic energy.
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Kinetic energy
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Water potential
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Both
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None
C
Correct answer
Explanation
Higher water concentration means more free water molecules, which increases both the kinetic energy of the water and the water potential of the system.
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Cool it down
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Heat it up
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Slow the particles down
B
Correct answer
Explanation
Heating a reaction increases the kinetic energy of the particles, causing them to collide more frequently and with greater force. This increased collision rate accelerates the chemical reaction.
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Chemical Changes are easily reversible.
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Physical Changes do not create new products.
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Physical Changes are not easily reversible.
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Chemical changes do not create new products.
B
Correct answer
Explanation
A physical change alters the form or appearance of a substance but does not change its chemical composition, meaning no new products are created. Chemical changes, conversely, result in the formation of new substances.