How does activation energy affect a chemical reaction ?
2 answers:
Answer: Option (B) is the correct answer.
Explanation:
Activation energy is the minimum amount of energy required to start or initiate a chemical reaction.
More is the activation energy more difficult is it for the reactants to participate in reaction.
Whereas a catalyst helps in increasing the rate of a reaction by increasing the energy of reactant molecules so that they can cross the activation energy barrier and therefore, formation of products become faster.
Thus, we can conclude that activation energy affect a chemical reaction as it determines how difficult it is to start the reaction.
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Explanation:
- Evaporation is defined as a process in which liquid state of water is changing into vapor state.
So, we need to break the bonds of liquid substance in order to convert it into vapor state. And, energy is absorbed for breaking of bonds which means that evaporation is an endothermic process.
Hence, the statement evaporation of water is an exothermic process is false.
- When a hydrocarbon reacts with oxygen and leads to the formation of carbon dioxide and water then this type of reaction is known as combustion reaction.
A combustion reaction will always release heat energy. Hence, combustion reaction is exothermic in nature.
- When energy is transferred as heat from the surroundings to the system then it means energy is being absorbed by the system. And, absorption of heat is an endothermic process for which
is positive.
- Whereas when energy is transferred from system to the surrounding then it means energy is released by the system which is an exothermic process.
Hence, for an exothermic process value of is negative.
Thus, we can conclude that statements which are true are as follows.
- A combustion reaction is exothermic.
- When energy is transferred as heat from the system to the surroundings,
- For an endothermic reaction Deta H is positive.