C5.1 Exothermic and endothermic reactions / C6.2 Rate of reaction Flashcards
(59 cards)
How does increasing the concentration of a solution affect the rate of reaction?
It increases the rate of reaction by causing more frequent collisions between particles.
How does increasing the pressure of a gas affect the rate of reaction?
It increases the rate by pushing gas particles closer together, increasing collision frequency.
How does increasing the surface area of a solid affect the rate of reaction?
It increases the rate by exposing more particles to react, leading to more collisions.
How does increasing the temperature affect the rate of reaction?
It increases the rate by giving particles more energy to collide with enough force to react.
How does a catalyst affect the rate of reaction?
It increases the rate by lowering the activation energy needed for the reaction to occur.
What happens to a catalyst at the end of a reaction?
It remains unchanged and can be used again.
Name two practical methods to investigate the rate of a reaction.
1) Measuring change in mass. 2) Measuring the volume of gas produced.
What can you learn from a graph showing the rate of reaction?
You can interpret how fast a reaction occurs and how it changes over time.
Why does a higher concentration lead to more frequent collisions?
Because there are more particles in the same volume, increasing the chance of collision.
Why does increasing temperature increase both the frequency and energy of collisions?
Particles move faster and have more kinetic energy, making successful collisions more likely.
How does a catalyst lower the activation energy?
It provides an alternative reaction pathway with lower energy requirements.
What is the unit for rate of reaction when measuring gas?
cm³/s or cm³/min depending on the experiment.
What safety precaution should you take when a reaction produces gas?
Use a gas syringe or an inverted measuring cylinder to safely collect and measure the gas.
What would a steep slope on a rate-of-reaction graph indicate?
A fast reaction rate.
What does a flat line on a reaction graph indicate?
The reaction has finished – no further products are being formed.
Give one example of a fast reaction.
Combustion or an explosion.
Give one example of a slow reaction.
Rusting of iron.
What is meant by “successful collision”?
A collision where particles hit with enough energy to overcome the activation energy and react.
What is an exothermic reaction?
A reaction that transfers thermal energy to the surroundings, increasing the temperature.
What is an endothermic reaction?
A reaction that absorbs thermal energy from the surroundings, decreasing the temperature.
How does a reaction pathway diagram show an exothermic reaction?
The products are at a lower energy level than the reactants, with energy released.
How does a reaction pathway diagram show an endothermic reaction?
The products are at a higher energy level than the reactants, with energy absorbed.
What is meant by the term enthalpy change, ∆H?
It is the thermal energy change during a reaction; negative for exothermic and positive for endothermic reactions.
What is activation energy (Ea)?
The minimum energy that reacting particles must have to start a reaction.
