Rates Of Reaction And Energy Changes Flashcards
What is the rate of reaction
How quickly a reaction happens
How can the rate of reaction be observed
By measuring how quickly the reactants are used up or how quickly the products are formed
Precipitation for reaction rates
Mix 2 reactant solutions over X
Observe mark x through mixture and time how long it takes until you cant see the x
The faster it disappeares the faster the reaction
Change in mass for reaction rates
Measure rate of reaction that produces gas by using a mass balance
Quicker the reading drops the faster the reaction
Reaction has finished when reading on balance stops changing
Volume of gas given off in reaction rates
Use gas syringe to measure the volume of gas given off
More gas given off during a set time, faster the reaction
Reaction has finished when no more gas is produced
Plot graph, gas volume against time elapsed
What does a higher temperature mean for the rate of reaction
Higher temperature means higher rate of reaction
What does the rate off a chemical reaction depend on
How often reacting particles collide with each other
Particles need to collide with at least the activation energy for the collision to be succesful
Why does temperature increasing cause the rate to increase
Because the particles move faster so will have more collisions
What does increasing concentration or pressure do to rate
If a solution is more concentrated it means there are more particles of reactant in the same volume. This makes collisions more likely
In a gas increasing the pressure means that the particles are more crowded so will collide more
What does smaller solid particles or more surface area mean for rate
The particles will have more area to work on so the frequency of collisions will increase
What is a catalyst and what does it do
A catalyst is a chemical substance which increases the rate of reaction without being chemically changed or used up in the reaction
The reaction equation will stay the same
They decrease the activation energy, therefore more particles have the minimum amount of energy needed for the reaction to occur
What are enzymes and what do they do
They are biological catalysts
Speed up chemical reactions in living cells
Happens in respiration, photosynthesis and protein synthesis
