C8 Rates and Equilibrium Flashcards
What does the rate of a reaction tell us?
How fast reactants turn into products
Why is cotton wool used in the neck of the flask when investigating the rate of the decrease in mass in the reaction between HCL and Mg marble chips?
It allows gas to escape, while preventing spurts of liquid from escaping as it would affect the recorded mass
What is a source of error when using a gas syringe?
If the gas escapes before the bung is inserted
What is a random error and give an example
An error that causes readings to be spread about from their true value due results varying in an unpredictable way
(Can be reduced by taking more measurements and
calculating a mean)
What is a systematic error?
An error that causes readings to differ from the true value by a consistent amount each time a measurement is made
(Can be fixed by using a different technique)
Give two equations to find the rate of reaction of an experiment
Quantity of reactant used/product formed / Time
What does the collision theory state?
That for a reaction to occur, reactant particles must collide with sufficient energy at the correct orientation
What is the rate of reaction determined by?
The frequency of collisions at a successful orientation
How does increasing concentration affect the rate of reaction?
It means that there are more reactant particles in a constant volume, so there are more successful collisions in a given period, so the rate of reaction increases
How does an increasing surface area of a solid reactant affect the rate of reaction?
It increases the surface area : volume ratio, and there is a larger surface for particles to collide with, increasing the frequency of collisions, and as a result, increasing the rate of reaction
What area of a solid can particles in a solution only react with?
The surface
What is the activation energy of a reaction?
The minimum amount of energy required for reactant particles to react (collide successfully at the correct orientation)
Explain the effect of increasing temperature on the rate of reaction
Increasing the temperature increases the total kinetic energy of the particles, causing them to move faster, and the frequency of collisions to increase, increasing the rate of reaction. As well as this, it means that more particles have the energy to overcome the activation energy barrier and successfully collide
What does a catalyst do?
It increases the rate of a chemical reaction but isn’t used up
Why are catalysts important?
They allow reactions to be carried out quickly without needing a high temperature/pressure, saving money.
They can also be reused kek
How do catalysts increase the rate of reaction?
They provide a different pathway for a reaction to occur, one with a lower activation energy
How does increasing the pressure of a gas affect the rate of reaction?
An increasing pressure means that there are more gas particles in a given area, increasing the frequency of collisions
What effect does a catalyst have on the position of equillibrium?
None at all lol get trolled
If a forward reaction is endothermic, what 2 things can you say about the enthalpy change for the reverse reaction?
- It will be exothermic
- The amount of energy will be released as is taken in by the forward reaction
An aqueous solution of blue copper(II) ions can react with chloride ions to form a yellow copper compound. These solutions are mixed together, and it quickly turns green. When observed for a few more minutes no change in colour is detected, explain these observations.
The system has reached equilibrium , and the mixture contains both blue Cu (II) ions and the yellow copper compound, so the colours mix to form green
