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, is negative.
- For an endothermic reaction Deta H is positive.
Answer:
A
Explanation:
All of the other options are ways that could help the environment from the chemicals, but if they just continue to use the chemicals then it would hurt the environment
Answer:
D. the polar liquid will have the higher boiling point, since its molecules have dipole-dipole interactions.
Explanation:
<em>Dipole-Dipole interactions</em> take place only between polar molecules.
They consist of attractions between the negative end of a polar molecule and the positive end of another polar molecule. For example, between the O atom and the H atom in water.
These attractions are not present in a non-polar liquid, so its molecules will be more loosely held together and its boiling point will be lower.
The two structures at the right of the image are the greatest contributors to the resonance structure of malachite green.
<h3>What is resonance structure?</h3>
In some cases, one single structure is insufficient to explain the properties of a substance. Now, we know that in such cases we have to invoke more than one structure in order to efficiently discuss the chemistry of the compounds in question.
In this case, we can see from the image that the three structures of malachite green are all resonance structures. However, the two structures at the right hand side are the greatest contributors because they are more conjugated. Hence, the two structures at the right of the image are the greatest contributors to the resonance structure of malachite green.
Learn more about resonance structure:brainly.com/question/23287285
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Answer:
0.3 s.
Explanation:
Half-life of a first order reaction is defined as the the time taken for any fraction of the reaction to complete is independent of the initial concentration.
Half-life of a first order reaction, t° = 0.693/k
where,
t° = half-life of the reaction
k = rate constant
= 2.3 s^-1
Therefore,
t° = 0.693/2.3
= 0.30 s.
