Answer:
Sublimation is defined as the direct transition of a substance from solid state to gaseous state. The latent heat of sublimation is the sum of heat required for conversion from solid to liquid and heat required for conversion from liquid to gas. As in sublimation solid substance directly goes to gaseous state therefore, it is very difficult to find the components of latent heat of sublimation. This is the issue which arises in determining latent heat of sublimation.
On the other hand, when substance is melted it physically goes from solid to liquid. One can easily measure the heat required for this conversion.
Latent heat determination challenges differ between substances that sublime and those that melt. Sublimation involves a solid-to-gas change, typically under low pressure, making it difficult to contain the gas and measure accurate energy changes. In contrast, melting transitions from solid to liquid, with challenges in accurately measuring temperature change and ensuring complete melting.
When determining the latent heat of substances, different issues can arise depending on if the substance sublimes or melts. Melting is a transition from a solid to a liquid state, while sublimation involves a transition directly from a solid to a gas state.
One issue that might arise would be managing the environmental conditions. Sublimation often happens at low pressure, and ensuring a consistent low-pressure environment can be challenging. Also, because the substance is transitioning directly to a gas, it may be more difficult to accurately measure the energy change as some gas may escape during the process.
For melting substances, the issues are different as one is transitioning from a solid to a liquid state, and it's typically measured at atmospheric pressure. Accuracy in measuring the temperature change and ensuring the entire substance has completely melted are potential challenges.
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Wood
Adhesives
Cooking oil
Answer: ADHESIVES
Explanation: CORRECT ON K12 QUIZ
Explanation:
In an exothermic reaction, heat is released into the surroundings. In this type of reaction, energy of products is less than the energy of reactants.
In an endothermic reaction, heat is absorbed by the reactant molecules. In this type of reaction, energy of products is more than the energy of reactants.
Therefore, we can conclude that while performing an experiment involving a reaction between two chemicals, the scientist observes that the reaction container has become warm. The observation is an example of exothermic reaction.
B.Complex Machine
C.Compound Machine
D.Simple Machine
A rake is a simple machine. Thus, the correct option is D.
A simple machine is a mechanical device which changes the direction or magnitude of an applied force. In general, these machines can be defined as the simplest mechanisms which uses mechanical advantage also called as leverage to multiply the force. Usually the term refers to the six classical simple machines which were defined by Renaissance scientists including lever, wheel and axle, pulley, inclined plane, wedge, and screw.
A simple machine uses a single applied force to do the work against a single load force or friction. Ignoring the friction losses, the work done on the load force is equal to the work done by the applied force.
Therefore, the correct option is D.
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