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Description
Flashcards by Malachy Moran-Tun, updated more than 1 year ago
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Created by Malachy Moran-Tun
about 3 years ago
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| Question | Answer |
| What is the Rate of Reaction? | How Fast a Reaction Happens |
| How do Reactions Occur? | Particles collide with enough energy to react |
| What is the Minimum Amount of Energy for a Reaction to Occur Called? | The Activation Energy |
| How do you Increase the Rate of Reaction (generally)? | Increase the Frequency of Collisions or Increase the Energy of Collisions (so they're more successful) |
| How do you Calculate the Rate of Reaction? | Rate = Amount of Product Formed ÷ Time or Rate = Amount of Reactant Used ÷ Time |
| How do you Increase Rate of Reaction by Changing the Surface Area and why? | > Increasing the surface area to volume ratio > Usually done by decreasing size of pieces (powdering them etc.) but overall volume is the same > There is more surface for collisions to occur > Collisions occur more frequently - faster rate of reaction |
| How do you Increase Rate of Reaction by Changing the Concentration and why? | > Increasing the concentration > There are more reacting particles in the same volume > Collisions occur more frequently - faster rate of reaction |
| How do you Increase Rate of Reaction by Changing the Temperature and why? | > Increasing the temperature > Reactant particles have more energy > More kinetic energy means particles move faster > Particles moving faster collide more frequently - faster rate of reaction > Particles with more energy successfully react more frequently - faster rate of reaction |
| How do you Increase Rate of Reaction by Changing the Pressure and why? | > Increase the pressure > Same number of particles in a lower volume > Collisions occur more frequently - faster rate of reaction |
| How could you Test Rates of Reaction? | > Measure how quickly a precipitate forms (if applicable) > Measure a change in mass (usually by gas being given off) > Measure a volume of gas given off |
| How would you Test Rates of Reaction by using a Precipitate being Formed? | > Put a piece of paper with an X below the flask > Mix the two solutions > Time how long it takes for the X to "disappear" > Result is Subjective |
| How would you Test Rates of Reaction by using the Change in Mass? | > Place the flask on scales > Mix the two solutions > Bung the flask with cotton wool (for safety) > Measure how quickly the mass decreases |
| How would you Test Rates of Reaction by using the Volume of Gas? | > Mix the two solutions > Bung the flask with either a gas syringe or upside-down measuring cylinder filled with water > Measure the volume against the time elapsed > Faster the volume increases, the faster the reaction |
| When plotting Rates of Reaction on a Graph, how do you determine the Rate? | The gradient |
| How do you calculate Gradient? | Curved line: Draw a tangent off a specific point then Straight line: Gradient = Δy ÷ Δx (Δ = change in) |
| What do Catalysts do? | Increase the Rate of Reaction without being Chemically Changed or Used Up |
| How do Catalysts Work? | Decrease the Activation Energy needed for a Reaction to Occur by providing an Alternative Reaction Pathway |
| What are Enzymes and Where are they Found? | Biological Catalysts found in Living Cells / Organisms |
| What is an Exothermic Reaction? | A reaction which gives out energy to the surroundings - rise in temperature of the surroundings |
| What is an Endothermic Reaction? | A reaction which takes in energy from the surroundings - fall in temperature of the surroundings |
| What is a Reaction Profile? | A Graph which shows the Energy Levels of Reactants and Products in a Reaction |
| How do you tell if a Reaction is Exothermic on a Reaction Profile | > Products have a Lower Energy than the Reactants > Difference in Height Represents the Energy Given Out |
| How do you tell if a Reaction is Endothermic on a Reaction Profile | > Products have a Higher Energy than the Reactants > Difference in Height Represents the Energy Taken In |
| On a Reaction Profile, what is the Activation Energy? | Energy Difference between the Reactants and the Peak of the Curve |
| Which of the Following Reactions are Exothermic, Endothermic or Both (depending on the elements): > Dissolving Salts > Neutralisation > Displacement > Precipitation | > Dissolving Salts - Both > Neutralisation - Both (usually Exo) > Displacement - Exothermic > Precipitation - Exothermic |
| Is Breaking Chemical Bonds Endothermic or Exothermic | Endothermic; it requires energy |
| Is Forming Chemical Bonds Endothermic or Exothermic | Exothermic; it releases energy |
| How do you Calculate Overall Energy Change? | Overall Energy Change = Energy Required to Break Bonds - Energy Released by Forming Bonds (Example in Revision Guide) |
| and you are the be done | grammer amirite |
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