Endothermic, Exothermic & Rates Of Reaction
- 1.
What does exothermic mean ?
- A.
Releasing heat
- B.
Absorbing heat
- C.
Producing heat
Correct Answer
A. Releasing heatExplanation
Exothermic refers to a process or reaction that releases heat to its surroundings. This means that during an exothermic reaction, the system loses heat energy, resulting in an increase in the temperature of the surroundings. Examples of exothermic reactions include combustion, such as burning wood or gasoline, where heat is released as a byproduct.Rate this question:
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- 2.
Is melting an endothermic reaction ?
- A.
Yes
- B.
No
- C.
Option 4
Correct Answer
A. YesExplanation
Melting is an endothermic reaction because it requires energy input to break the bonds between the solid particles and convert them into a liquid state. The energy is absorbed from the surroundings, causing a decrease in temperature. Therefore, melting is considered an endothermic process.Rate this question:
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- 3.
What is a catalyst ?
- A.
A chemical that changes while speeding up the rate of reaction
- B.
A chemical to slow down the rate of reaction
- C.
A chemical that speeds up the rate of a reaction without being changed in the process.
- D.
A chemical that reacts to form a new product while speeding up the rate of reaction
Correct Answer
C. A chemical that speeds up the rate of a reaction without being changed in the process.Explanation
A catalyst is a substance that increases the rate of a chemical reaction without being consumed or altered in the process. It provides an alternative pathway for the reaction to occur, lowering the activation energy required for the reaction to take place. This allows the reaction to proceed at a faster rate, but the catalyst itself remains unchanged and can be used repeatedly.Rate this question:
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- 4.
Why does the hull of an ocean going ship rust quickly ?
- A.
Because the ocean going ship is always in the sea water
- B.
Because the sea water speeds up the reaction of the iron rusting
- C.
Because the iron's quality is bad
Correct Answer
B. Because the sea water speeds up the reaction of the iron rustingExplanation
The hull of an ocean-going ship rusts quickly because sea water speeds up the reaction of iron rusting. Sea water contains dissolved salts and minerals, which act as electrolytes and enhance the corrosion process. This accelerates the oxidation of iron, leading to the formation of rust. Additionally, the constant exposure to moisture and saltwater creates an ideal environment for rust to develop and spread rapidly on the ship's hull.Rate this question:
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- 5.
Why does the rate of reaction speed up when it is heated ? Use the particle theory to explain.
- A.
Because increasing the temperature makes the particles become bigger and so it can touch other particles more quickly and react.
- B.
Because increasing temperature gives particles more energy. When particles moves faster, it increases the chances of collision and collisions are harder.
- C.
Because increasing the temperature causes the particles to rise quickly.
Correct Answer
B. Because increasing temperature gives particles more energy. When particles moves faster, it increases the chances of collision and collisions are harder.Explanation
Increasing the temperature of a reaction provides more energy to the particles involved. This increase in energy causes the particles to move faster and collide with each other more frequently. As a result, the chances of successful collisions, where the particles react, are increased. Additionally, the collisions become more forceful, as the increased energy leads to stronger impacts. Therefore, the rate of reaction speeds up when the temperature is increased.Rate this question:
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- 6.
A lump of iron reacts faster than powdered iron. Is it true or false ?
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Powdered iron reacts faster than a lump of iron because the smaller particle size provides a larger surface area for the reactants to come into contact with each other. This increased surface area allows for more frequent and efficient collisions between the iron particles and the reactants, resulting in a faster reaction rate.Rate this question:
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- 7.
Why does a metal with a bigger surface area react faster than a metal with a smaller surface area ?
- A.
Because more particles are exposed to collision with other particles causing a faster rate of reaction.
- B.
Because the particles can move about more freely to collide causing a faster reaction.
- C.
Because less particles are exposed to collision with other particles causing a faster rate of reaction.
Correct Answer
A. Because more particles are exposed to collision with other particles causing a faster rate of reaction.Explanation
A metal with a bigger surface area reacts faster than a metal with a smaller surface area because more particles are exposed to collision with other particles. This increased surface area allows for a greater number of reactant particles to come into contact with each other, leading to a higher rate of reaction.Rate this question:
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- 8.
What are the factors affecting the rate of reaction ?
- A.
Concentration
- B.
Density
- C.
Catalsyts
- D.
Mass
- E.
Surface Area
- F.
Temperature
- G.
Volume
Correct Answer(s)
A. Concentration
C. Catalsyts
E. Surface Area
F. TemperatureExplanation
The factors affecting the rate of reaction are concentration, catalysts, surface area, and temperature. Concentration refers to the amount of reactants present, with higher concentrations leading to more collisions and increased reaction rates. Catalysts are substances that speed up reactions by lowering the activation energy required. Increasing the surface area of the reactants exposes more molecules to each other, resulting in more collisions and faster reactions. Temperature affects the rate by increasing the kinetic energy of the particles, leading to more frequent and energetic collisions.Rate this question:
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Current Version
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May 10, 2023Quiz Edited by
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Jul 03, 2014Quiz Created by
Christielow
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