Questions and Answers
What 4 main things affect the rate of reaction?
Temperature, concentration, surface area, catalyst (such as enzymes)
How does temperature affect the rate of reaction?
Higher temperatures mean there is more energy therefore the particles move faster and collide more often and more violently.
How does concentration affect the rate of reaction?
Increased concentration of the reactants means there are more particles in the same volume therefore more collisions occur each second.
Why does surface area affect the rate of reaction?
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What are catalysts and why do they speed up reactions?
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What is an enzyme and how do they work?
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What is activation energy?
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What is a reaction?
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What does a steep gradient in a graph mean?
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What does a horizontal line on a graph mean?
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What is the rate of reaction?
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What is the limiting reagent?
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Give two examples of fast reactions.
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Give two examples of slow reactions.
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What equation is used to calculate the rate of reaction?
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What is the balanced symbol equation for the reaction between calcium carbonate and hydrochloric acid and what are the products of the reaction?
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Describe the disappearing cross reaction to investigate the effect of temperature on rate of reaction in a reaction between hydrochloric acid and sodium thiosulphate solution.
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How do you calculate rate?
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How do you convert from Celsius to Kelvin?
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What is meant by an exponential relationship?
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Why does the rate of reaction increase with temperature?
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How do you recover a solid catalyst from a reaction mixture?
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What is the best catalyst for decomposing hydrogen peroxide?
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What is the symbol equation for the decomposition of hydrogen peroxide?
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Why is it important to use catalysts in industry?
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Study Notes
Factors Affecting Reaction Rate
- Rate of reaction is influenced by temperature, concentration, surface area, and catalysts.
Temperature and Reaction Rate
- Higher temperatures result in increased particle energy, leading to faster motion and more frequent collisions.
Concentration and Reaction Rate
- Increased concentration of reactants raises particle number in a given volume, causing more collisions per second.
Surface Area and Reaction Rate
- Greater surface area enhances contact between solid particles and reactants in solution, increasing collision frequency.
Catalysts
- Catalysts are substances that accelerate reactions without being consumed, providing alternative pathways with lower activation energy.
Enzymes
- Enzymes are specific biological catalysts effective under particular temperature and pH conditions; extreme conditions can denature them.
Activation Energy
- Activation energy is the minimum energy needed to break initial bonds for a chemical reaction to initiate.
Reaction Definition
- A reaction occurs when particles collide with sufficient energy and proper orientation to break bonds.
Graph Interpretation
- A steep gradient in a reaction rate graph indicates a fast reaction, while a horizontal line signifies that the reaction has ceased.
Rate of Reaction
- Rate of reaction measures how quickly products form from reactants.
Limiting Reagent
- The limiting reagent is the reactant that is used up first, halting the reaction.
Fast Reactions
- Examples of fast reactions include salt dissolving in water and the combustion of magnesium.
Slow Reactions
- Examples of slow reactions are photosynthesis and electrolysis.
Calculating Rate of Reaction
- Rate of reaction can be calculated as the amount of reactant or product divided by time taken.
Balanced Reaction Equation
- The reaction between calcium carbonate and hydrochloric acid is: CaCO3(s) + 2HCl(aq) -> CaCl2(aq) + H2O(l) + CO2(g)
Disappearing Cross Experiment
- Investigating temperature effects involves measuring hydrochloric acid and sodium thiosulphate, heating to a target temperature, and timing the disappearance of a marked 'X'.
Rate Calculation
- Rate can also be calculated as the inverse of time taken (1/time).
Temperature Conversion
- To convert Celsius to Kelvin, add 273.
Exponential Relationship
- An exponential relationship indicates that reaction rate significantly increases with temperature.
Temperature Impact on Rate
- Increased temperature accelerates particle movement, enhancing collision frequency, orientation, and activation energy availability, leading to more successful collisions.
Recovering Solid Catalysts
- Solid catalysts can be recovered through filtration, where they remain on the filter paper as insoluble solids.
Best Catalyst for Hydrogen Peroxide
- Manganese dioxide serves as the most effective catalyst for decomposing hydrogen peroxide.
Decomposition of Hydrogen Peroxide Equation
- The symbolic equation is: 2H2O2 --(MnO2)--> 2H2O + O2.
Industrial Importance of Catalysts
- Catalysts are vital in industry to reduce costs by lowering the high activation energy required for many reactions.
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Description
This quiz explores the various factors affecting the rate of chemical reactions, including temperature, concentration, surface area, and catalysts. Delve into how each factor plays a crucial role in influencing reaction dynamics and the importance of enzymes in biological processes.