Topic 7 - Rates of Reaction and Energy Changes Flashcards
What is the rate of reaction?
how quickly a reaction happens
What is the equation for rate of reaction?
Amount of reactants used or amount of products used / time
What are the 3 examples rate of reaction can be mesured?
Precipitation
Change in mass ( Usually gas given off)
Volume of gas given off
Precipitation
Rate of reaction
- works when mixing two clear solutions, that precipitate once reacted
- Mix the two and place the flask on a surface with a mark
- Observe how long it takes for the mark to be obscured through the precipitate
This result if subjective
Change in mass ( usually given off)
Experemnt of rate of reaction
Rate of reaction that produces gas using a balance
The quicker the mass/ gas is lost, the quicker the reaction.
The reaction has finished once the mass stops changing
You can plot the results of mass aganst time
If the gas is harmfull, use a gas cupboard
The volume of gas given off ( rate of reaction experement )
Involves the use of gas syringe to mesure gas given off
The more gas given off during a time set interval, the faster the reaction. the reaction is finished when no more gas is produced
Graph of gas volume/ time elapsed
Use the rightsize of syringe, if too much gas can blow the plunger off
What is an exothermic reaction?
A reaction which gives out energy, usually in the form of heat, causing a rise in temp to the surroundings
What is an endothermic reaction?
A reaction which absorbs energy, usually in the form of heat, causing a fall in temp to the surroundings
What does an exothermic reaction look like on an energy/ time graph?
Reactants above products, energy is given out, lump leading down
What does an endothermic reaction look like on an energy/ time graph?
Reactants below products, energy is taken in, lump leading up
What is activation energy?
Minimum amount of eneryg needed for the bonds to break and a reaction to start
Where is activation energy on and energy/time graph?
Between the reactants and highest peak of line
