Rate Of Reaction (topic 6) Flashcards
What does this symbol mean ⇌
Means the reaction is reversible.
[The reactants become products and the products can become reactants again using the same process.]
What happens when you HEAT hydrated copper sulfate?
The water is taken off the hydrated copper sulfate and leaves anhydrous copper sulfate + water
[ hydrated copper sulfate ⇌ anhydrous copper sulfate + water ]
Key points of reversible reactions:
If a reversible reaction is EXOTHERMIC in one direction, the opposite direction is ENDOTHERMIC.
The same amount of energy is transferred / reversed.
The FOWARD reaction is always REACTANTS turning into PRODUCTS.
How can equilibrium be reached?
In a closed system meaning no products/ reactants can be added or escaped.
State 2 main ways to increase the rate of reaction
Increase the number of collisions
Increase the amount of kentic energy so more collisions lead to a reaction.
How to measure the rate of reaction
Rate of reaction= amount of products formed or reactants used ÷ time
State 4 variables that change the rate of reaction & how
CONCENTRATION: increasing concentration of reactants increases the number of collisions between particles therefore increasing rate of reaction
TEMPERATURE: increasing the temperature, increases the rate of reaction due to the particles having more energy. This means the particles move faster & collide more frequently.
CATALYST: they speed up reactions without being changed, they lower the activation energy which then increases the amount of successful collisions, therefore increases the rate of reaction.
SURFACE AREA: larger surface area has a higher rate of reaction. Small PIECES gives us more surface area
Practical for hydrated copper sulfate
1) place a spatula of copper sulphate crystals on a lid
2) place on a clay triangle on a tripod
3) use a Bunsen burner to heat vigorously
4) leave to cool on the tripod and add distilled water to the crystals
5) Record two observations that you can see happening
How do can you measure the rate of reaction?
1) change in mass using a mass balance: a reaction that produces gas can be measured with a mass balance as the gas is released, the mass disappearing is measured on the balance. The quicker the reading drops the faster the reaction is
2) the volume in gas given off using a gas syringe: the more gas given off during a given time interval, the faster the reaction
