Chemistry- Chemical Reactions And Collision Theory Test
If you are a chemistry student, this test is perfect for testing your subject knowledge. It has questions about various chemical reactions, the role of enzymes, collision theory, etc. Let's see if you can score a 100% or not. All the best!
- 1.
Consider the following reversible, exothermic chemical reaction: 2C2H2(g) + 5O2(g) ↔4CO2(g) + 2H2O(g) All BUT one of the conditions will cause equilibrium to shift right and produce more of the products. Which change will cause the reaction to shift to the left?
- A.
Adding oxygen
- B.
Adding CO2
- C.
Increasing the pressure
- D.
Decreasing the temperature
Correct Answer
B. Adding CO2Explanation
Adding CO2 to the reaction will shift the equilibrium to the left and produce less of the products. This is because adding CO2 to the reaction will increase the concentration of the reactant, which will favor the reverse reaction and decrease the concentration of the products. According to Le Chatelier's principle, when a stress is applied to a system in equilibrium, the equilibrium will shift in the direction that reduces the stress.Rate this question:
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- 2.
Which one do you like? Collision theory states that when two molecules collide with each other with sufficient energy and hit in the proper orientation, a bond is formed. Which action will increase the rate of reaction in a closed container?
- A.
Adding an inert gas
- B.
Expand the volume
- C.
Increase the temperature
- D.
Decrease the concentration
Correct Answer
C. Increase the temperatureExplanation
Increasing the temperature increases the kinetic energy of the molecules, causing them to move faster. This leads to more frequent and energetic collisions between molecules, increasing the chances of successful collisions that result in bond formation. Therefore, increasing the temperature will increase the rate of reaction in a closed container.Rate this question:
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- 3.
When a mixture is stirred
- A.
The rate of dissolving stops
- B.
The rate of dissolving will increase
- C.
The rate of dissolving will decrease
- D.
The rate of dissolving will remain constant
Correct Answer
B. The rate of dissolving will increaseExplanation
When a mixture is stirred, the rate of dissolving will increase. Stirring helps to increase the contact between the solute and the solvent, allowing for more efficient mixing and dissolving. This increased contact and mixing leads to a faster dissolution of the solute in the solvent, resulting in an increased rate of dissolving.Rate this question:
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- 4.
All BUT one action would increase the rate at which solid metal will react with a acid solution. That is
- A.
Decrease the molarity of the acid
- B.
Break the metal into smaller pieces
- C.
Increase the temperature of the solution
- D.
Increase the concentration of the acid solution
Correct Answer
A. Decrease the molarity of the acidExplanation
Decreasing the molarity of the acid would decrease the concentration of acid particles in the solution. Since the rate of reaction depends on the collision frequency between reactant particles, decreasing the molarity would result in fewer acid particles available to react with the metal. Therefore, decreasing the molarity of the acid would decrease the rate at which solid metal reacts with the acid solution.Rate this question:
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- 5.
Kc =[CO2]2/[CO]2[O2] is the equilibrium constant for which chemical reaction?
- A.
CO + O2 ↔ CO2
- B.
2CO + O2 ↔ 2CO2
- C.
2CO2 ↔ 2CO + O2
- D.
CO + 1/2 O2 ↔ CO2
Correct Answer
B. 2CO + O2 ↔ 2CO2Explanation
The equilibrium constant expression, Kc = [CO2]^2/[CO]^2[O2], indicates that the equilibrium constant is for the chemical reaction 2CO + O2 ⇌ 2CO2.Rate this question:
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- 6.
In cells, __________ are proteins that are needed to lower the amount of energy required to start chemical reactions.
- A.
Acid
- B.
Enzymes
- C.
Products
- D.
Substrates
Correct Answer
B. EnzymesExplanation
Enzymes are proteins that act as catalysts in cells, lowering the activation energy needed to initiate chemical reactions. They speed up the rate of reactions by binding to the reactant molecules and facilitating the formation of product molecules. Enzymes are specific to certain substrates, meaning they can only catalyze specific reactions. Overall, enzymes play a crucial role in cellular metabolism by increasing the efficiency of biochemical reactions.Rate this question:
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- 7.
Jake wants to quickly dissolve Gatorade in a pitcher. What would help Jake INCREASE the rate at which his Gatorade dissolves?
- A.
Adding sugar
- B.
Cooling the mixture
- C.
Adding more Gatorade
- D.
Stirring the mixture
Correct Answer
D. Stirring the mixtureExplanation
Stirring the mixture would help increase the rate at which the Gatorade dissolves. Stirring increases the surface area of the Gatorade particles, allowing more contact with the solvent (water) and enhancing the process of dissolving. This helps to break down the solute particles and distribute them more evenly throughout the solvent, leading to a faster dissolution.Rate this question:
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- 8.
CO (g) + 2H2 (g) ↔ CH3OH (g) The equilibrium reaction can be shifted to form more products by _____________.
- A.
Decreasing the pressure.
- B.
Adding more hydrogen.
- C.
Adding more methanol (CH3OH (g)).
- D.
Adding a catalyst.
Correct Answer
B. Adding more hydrogen.Explanation
Adding more hydrogen can shift the equilibrium reaction to form more products because according to Le Chatelier's principle, increasing the concentration of one of the reactants (in this case, hydrogen) will cause the reaction to shift in the direction that consumes that reactant. By adding more hydrogen, the reaction will shift to the right, favoring the formation of more methanol.Rate this question:
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- 9.
Hydrogen peroxide is a harmful by-product of normal metabolic activity. In order to prevent damage, hydrogen peroxide must be broken down into water and oxygen quickly. What would speed up the decomposition of hydrogen peroxide?
- A.
A catalyst
- B.
bubbling in oxygen
- C.
Decreasing the temperature
- D.
Adding more hydrogen peroxide
Correct Answer
A. A catalystExplanation
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. In the case of hydrogen peroxide, a catalyst would speed up the decomposition of hydrogen peroxide into water and oxygen. This is because the catalyst provides an alternative reaction pathway with lower activation energy, allowing the reaction to occur more quickly. Therefore, adding a catalyst would speed up the decomposition of hydrogen peroxide.Rate this question:
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- 10.
Why do we say that "an enzyme is reusable"?
- A.
The enzyme does not actively take part in the reaction. It just indicates that the reaction is complete.
- B.
Enzymes react with the substrate to form products and become denatured in the process.
- C.
Enzymes ensure that the reaction continues without inhibition even if conditions such as temperature and PH are changed.
- D.
The products of the reaction are released from the active sites of the enzyme, allowing other substrate molecules to bind with the sites.
Correct Answer
D. The products of the reaction are released from the active sites of the enzyme, allowing other substrate molecules to bind with the sites.Explanation
Enzymes are considered reusable because after catalyzing a reaction, the products are released from the active sites of the enzyme. This allows the enzyme to be available for further reactions and bind with other substrate molecules. The enzyme itself does not undergo any permanent changes or get consumed in the reaction, making it available to catalyze multiple reactions.Rate this question:
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- 11.
Collision theory states that for a chemical reaction to occur the reacting particles must collide with one another. In order for collisions to be successful, reacting particles must collide with sufficient energy and in the correct orientation to produce a temporary intermediate product, the activated complex. ____________ energy is the minimum energy required for a successful collision.
- A.
Activation
- B.
Collision
- C.
Kinetic
- D.
Potential
Correct Answer
A. ActivationExplanation
Activation energy is the minimum energy required for a successful collision. This energy is needed to break the bonds in the reactant molecules and form new bonds in the products. Without sufficient activation energy, the collision will not lead to a successful reaction.Rate this question:
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- 12.
Increasing the temperature, as noted in the graph, increases the rate of this chemical reaction. What is the relationship between increased temperature and activation energy in a typical chemical reaction?
- A.
As the kinetic energy of the substances increases, the overall activation energy also increases.
- B.
The proportion of collisions that can overcome the activation energy for the reaction increases with temperature.
- C.
Although the average kinetic energy of the colliding substances increases, this has no influence on activation energy.
- D.
The proportion of collisions that can overcome the activation energy for the reaction decreases as temperature increases.
Correct Answer
B. The proportion of collisions that can overcome the activation energy for the reaction increases with temperature.Explanation
According to the given information, increasing the temperature increases the rate of the chemical reaction. This suggests that more collisions are occurring between the reactant molecules. The activation energy is the minimum energy required for a collision to result in a successful reaction. Therefore, as the temperature increases, the kinetic energy of the substances also increases, allowing a greater proportion of collisions to have enough energy to overcome the activation energy and proceed with the reaction.Rate this question:
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- 13.
According to le Châtelier’s principle if a system in equilibrium is subjected to a change in all BUT one of these conditions, there will be a tendency for a net reaction in the direction that reduces the effect of this change.
- A.
Pressure
- B.
Temperature
- C.
Addition of a new reactant
- D.
Number of moles of any component
Correct Answer
C. Addition of a new reactantExplanation
According to Le Chatelier's principle, if a system in equilibrium is subjected to a change, it will respond in a way that minimizes the effect of that change. In this case, the correct answer is "Addition of a new reactant." When a new reactant is added to a system at equilibrium, the concentration of that reactant increases. To reduce the effect of this change, the system will shift in the direction that consumes the added reactant, thus restoring equilibrium. This can be achieved by shifting the reaction towards the product side, resulting in a net reaction in that direction.Rate this question:
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- 14.
Zn + 2HCl ---> ZnCl2 + H2 In the lab, zinc granules react fairly slowly with dilute hydrochloric acid. Which of these would MOST help to speed up the chemical reaction?
- A.
Remove a catalyst
- B.
Lower the temperature
- C.
Use larger pieces of zinc
- D.
Increase the HCL concentration
Correct Answer
D. Increase the HCL concentrationExplanation
Increasing the HCl concentration would help to speed up the chemical reaction between zinc and hydrochloric acid. This is because a higher concentration of HCl means there are more HCl molecules available to react with the zinc granules. Increasing the concentration increases the collision frequency between the reactant particles, leading to a higher reaction rate.Rate this question:
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- 15.
The Collision Theory explains how chemical reactions occur and why different reactions have different reaction rates. The idea behind the theory basically states thet atoms must collide in order for a chemical reaction to take place. If this theory is true, what would happen in a chemical reaction if you were to increase the concentration of HCl in the reaction: Mg + 2HCl → MgCl2 + H2
- A.
The reaction would not proceed
- B.
The reaction rate would increase
- C.
The reaction rate would decrease
- D.
There would be no change in the reaction rate
Correct Answer
B. The reaction rate would increaseExplanation
Increasing the concentration of HCl in the reaction would increase the number of collisions between the HCl molecules and the magnesium atoms. According to the Collision Theory, an increase in the concentration of reactants leads to an increase in the frequency of collisions, which in turn increases the reaction rate. Therefore, increasing the concentration of HCl would result in an increased reaction rate.Rate this question:
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- 16.
In a chemical reaction, when particle size is reduced, the rate of reaction increases because of increased surface area of the reactants. Why would increased surface area increase reaction rate?
- A.
It increases the number of collisions among particles.
- B.
It decreases the activation energy.
- C.
It increases the concentration.
- D.
It decreases the temperature.
Correct Answer
A. It increases the number of collisions among particles.Explanation
When the particle size is reduced, the surface area of the reactants increases. This means that there is more area available for the reactant particles to come into contact with each other. As a result, the number of collisions among particles increases. Since collisions are necessary for a chemical reaction to occur, an increased number of collisions leads to a higher reaction rate. Therefore, increased surface area increases the number of collisions among particles, which in turn increases the reaction rate.Rate this question:
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- 17.
This graph represents the energy flow of a endothermic reaction. While working on a experiment, you re-graph your results and notice that the shape of the graph is the same, but the amount of activation energy needed for the reaction to was lower. Which of these would best describe why this occurred?
- A.
Additional reactants were added.
- B.
A catalyst was added to the reaction.
- C.
The temperature in the room was lower.
- D.
There were flaws in your initial design
Correct Answer
B. A catalyst was added to the reaction.Explanation
The addition of a catalyst to a reaction lowers the activation energy required for the reaction to occur. This is because a catalyst provides an alternative pathway for the reaction to proceed, which has a lower activation energy barrier. Therefore, the shape of the graph remains the same, but the amount of activation energy needed is reduced.Rate this question:
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- 18.
What MUST ALWAYS be true for a chemical reaction to occur?
- A.
There must be a catalyst present.
- B.
The system must be at a high temperature.
- C.
The reactants’ concentrations must be high.
- D.
The reactant particles must effectively collide.
Correct Answer
D. The reactant particles must effectively collide.Explanation
For a chemical reaction to occur, the reactant particles must effectively collide. This means that the particles must come into contact with each other in a way that allows them to interact and rearrange their atoms to form new substances. Without effective collisions, the reactants will not be able to break their existing bonds and form new ones, preventing the reaction from taking place. Catalysts, high temperatures, and high reactant concentrations can all increase the likelihood of effective collisions, but they are not necessary for a reaction to occur.Rate this question:
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- 19.
Amylase becomes denatured at a temperature of 80°C. During an experiment to study the effect of varying temperature on enzyme activity, amylase's reactivity with starch was measured at body temperature (37°C), and then again at an increased temperature of 42°C. How would this increase in temperature affect the experiment?
- A.
The reaction will stop
- B.
The enzyme would become inactive
- C.
The rate of the reaction will increase
- D.
The rate of the reaction will decrease
Correct Answer
C. The rate of the reaction will increaseExplanation
The increase in temperature from 37°C to 42°C would cause the rate of the reaction to increase. This is because enzymes generally have an optimal temperature at which they function most efficiently. In this case, the increase in temperature is within the range where amylase is still active and functional. As a result, the enzyme's reactivity with starch would be enhanced, leading to an increase in the rate of the reaction.Rate this question:
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- 20.
Brad and Matt are working in the lab. They noticed that when they mixed two dilute solutions together, the reaction between them happened very slowly. Which of Matt's suggestions would BEST help to increase the rate of this reaction?
- A.
Increase the concentration of both solutions
- B.
Decrease the concentration of both solutions
- C.
Increase the concentration of one of the solutions
- D.
Decrease the concentration of one of the solutions
Correct Answer
A. Increase the concentration of both solutionsExplanation
Increasing the concentration of both solutions would increase the number of reactant particles per unit volume. This would result in a greater frequency of successful collisions between the reactant particles, leading to an increase in the rate of the reaction.Rate this question:
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- 21.
Based on the solubility chart, which of the listed salts is the most soluble at 25 °C?
- A.
Sodium nitrate
- B.
Sodium chloride
- C.
Potassium nitrate
- D.
Potassium chlorate
Correct Answer
A. Sodium nitrateExplanation
Sodium nitrate is the most soluble salt at 25°C based on the solubility chart.Rate this question:
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- 22.
Which area of chemistry is concerned with reaction rates?
- A.
Inorganic
- B.
Kinetics
- C.
Organic
- D.
Redox
Correct Answer
B. KineticsExplanation
Kinetics is the area of chemistry that is concerned with reaction rates. It focuses on studying the speed at which chemical reactions occur and the factors that influence their rates. This includes investigating the effect of temperature, concentration, catalysts, and other variables on the rate of a reaction. By understanding reaction rates, scientists can better understand and control chemical reactions, which is crucial for various applications in industries such as pharmaceuticals, materials science, and environmental science.Rate this question:
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- 23.
Usually, when the temperature is increased, what will happen to the rate of dissolving?
- A.
It will stop.
- B.
It will increase.
- C.
It will decrease.
- D.
It will remain the same.
Correct Answer
B. It will increase.Explanation
When the temperature is increased, the rate of dissolving generally increases. This is because higher temperatures provide more energy to the particles, causing them to move faster and collide more frequently. As a result, the solute particles are more likely to separate from each other and mix with the solvent, leading to a faster dissolving process.Rate this question:
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- 24.
Consider this reaction taking place in a closed 2 liter container: 2SO2(g) + O2(g) → 2SO3(g) If the volume of the container is decreased to 1 liter, what will happen to the equilibrium of the reaction?
- A.
It will shift left.
- B.
It will shift right.
- C.
It will remain constant.
- D.
It will decrease by half.
Correct Answer
D. It will decrease by half.Explanation
When the volume of the container is decreased, according to Le Chatelier's principle, the system will try to counteract the change. In this case, decreasing the volume will increase the pressure inside the container. As a result, the equilibrium will shift in the direction that decreases the number of moles of gas. Since the reaction produces 2 moles of gas on the left side and 2 moles of gas on the right side, the equilibrium will shift to the left, where the number of moles of gas is smaller. This means that the concentration of SO2 and O2 will increase, while the concentration of SO3 will decrease, leading to a decrease in the overall reaction rate by half.Rate this question:
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- 25.
How do enzymes speed up chemical reactions? Enzymes
- A.
Lower the activation energy of chemical reactions.
- B.
Raise the temperature of the cell, speeding chemical reactions.
- C.
Store ATP, allowing more energy to be used in chemical reactions
- D.
Act as miniature transfer trucks gathering materials for chemical reactions, and placing them together.
Correct Answer
A. Lower the activation energy of chemical reactions.Explanation
Enzymes speed up chemical reactions by lowering the activation energy required for the reaction to occur. Activation energy is the energy needed to break the existing chemical bonds and initiate the reaction. By lowering this energy barrier, enzymes allow the reaction to proceed more quickly and efficiently. They do not raise the temperature of the cell or store ATP, nor do they act as transfer trucks.Rate this question:
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- 26.
Josh finds that there definitely is a relationship between enzyme action and temperature and graphs his results. The enzyme functions as a biological catalyst and has its optimum effectiveness at
- A.
30 degrees.
- B.
39 degrees.
- C.
59 degrees.
- D.
60 degrees.
Correct Answer
B. 39 degrees.Explanation
Based on the information given, Josh finds that there is a relationship between enzyme action and temperature. Enzymes are biological catalysts that speed up chemical reactions in the body. Enzymes have an optimum temperature at which they function most effectively. Therefore, the correct answer is 39 degrees, as this is the temperature at which the enzyme shows its highest level of effectiveness.Rate this question:
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- 27.
Amylase increases the rate at which starch is broken down into glucose. What kind of molecule is amylase?
- A.
Lipid
- B.
Enzyme
- C.
Carbohydrate
- D.
Nucleic acid
Correct Answer
B. EnzymeExplanation
Amylase is an enzyme. Enzymes are biological molecules that act as catalysts, speeding up chemical reactions in the body. Amylase specifically catalyzes the breakdown of starch into glucose, which is an important step in the digestion and absorption of carbohydrates. Therefore, amylase is the correct answer as it is the specific molecule responsible for this reaction.Rate this question:
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- 28.
Ea represents the
- A.
Energy released by the reaction.
- B.
Potential energy of the reactants.
- C.
Sum of the reactants and products energies.
- D.
Minimum energy particles must have in order to react.
Correct Answer
D. Minimum energy particles must have in order to react.Explanation
The correct answer is "minimum energy particles must have in order to react." This is because Ea represents the activation energy, which is the minimum energy required for a reaction to occur. Without this minimum energy, the particles will not have enough energy to overcome the energy barrier and react.Rate this question:
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- 29.
If you wanted to design an experiment to show that the solubility of sugar in tea varies according to the temperature, what variable would remain constant?
- A.
Volume of tea
- B.
Concentration of tea
- C.
Temperature of the tea
- D.
Amount of sugar dissolved
Correct Answer
D. Amount of sugar dissolvedExplanation
In order to design an experiment to show that the solubility of sugar in tea varies according to the temperature, the variable that would need to remain constant is the amount of sugar dissolved. By keeping the amount of sugar constant, any changes in solubility can be attributed solely to the temperature of the tea. This allows for a clear cause and effect relationship to be established between temperature and solubility.Rate this question:
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- 30.
H2CO3(aq) → CO2(aq) + H2O(l) After strenuous exercise, you breathe heavily, exhaling and removing CO2 from your body. The removal of CO2 causes a shift to the __________ and the ____________ of carbonic acid in the blood to help maintain a safe blood pH range.
- A.
Left; production
- B.
Right; production
- C.
Left; decomposition
- D.
Right; decomposition
Correct Answer
D. Right; decompositionExplanation
After strenuous exercise, the body produces more CO2 as a byproduct of cellular respiration. This leads to an increase in the concentration of CO2 in the blood, which can lower the blood pH and make it more acidic. To maintain a safe blood pH range, the body needs to remove excess CO2. This is achieved by exhaling CO2 from the lungs. When CO2 is exhaled, it reacts with water in the blood to form carbonic acid (H2CO3). This reaction is a decomposition reaction, as carbonic acid breaks down into CO2 and water. Therefore, the removal of CO2 causes a shift to the right and the decomposition of carbonic acid in the blood.Rate this question:
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- 31.
Which of these is a correct description of the relation?
- A.
Reaction rate remains unchanged with any temperature variation.
- B.
Reaction rate always reduces with an increase in temperature.
- C.
Reaction rate increases with a decrease in temperature.
- D.
Reaction rate is highest at a specific temperature.
Correct Answer
D. Reaction rate is highest at a specific temperature.Explanation
The correct answer is "Reaction rate is highest at a specific temperature." This means that the rate at which a reaction occurs is not constant with temperature changes, but rather reaches its maximum at a specific temperature. This is known as the reaction's optimum temperature, where the reactants have the highest energy and collide with the greatest frequency, leading to a faster reaction rate.Rate this question:
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- 32.
A catalyzed reaction will have a _____ activation energy, and this leads to a _____ in the reaction rate.
- A.
Lower, decrease
- B.
Lower, increase
- C.
Higher, decrease
- D.
Higher, increase
Correct Answer
B. Lower, increaseExplanation
A catalyzed reaction will have a lower activation energy because the catalyst provides an alternative reaction pathway with a lower energy barrier. This lower activation energy allows more reactant molecules to have sufficient energy to overcome the barrier and react, leading to an increase in the reaction rate.Rate this question:
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- 33.
Decreasing the temperature of a reaction decreases the reaction rate because
- A.
Decreasing the temperature also decreases the pressure.
- B.
Decreasing the temperature may cause a reactant to solidify.
- C.
Decreasing the temperature decreases the concentration of reactants.
- D.
Decreasing the temperature lowers the average kinetic energy of the reactants.
Correct Answer
D. Decreasing the temperature lowers the average kinetic energy of the reactants.Explanation
Decreasing the temperature lowers the average kinetic energy of the reactants. This is because temperature is a measure of the average kinetic energy of particles. When the temperature is decreased, the particles have less energy and move slower. As a result, they collide less frequently and with less energy, leading to a decrease in the reaction rate.Rate this question:
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Mar 22, 2023Quiz Edited by
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Mar 01, 2021Quiz Created by
Catherine Halcomb
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