april 2024 chemistry revision Flashcards
Endothermic reactions are [hotter/colder] than their surrounding environment
Endothermic reactions are colder than their surrounding environment.
Exothermic reactions are [hotter/colder] than their surrounding environment
Exothermic reactions are hotter than their surrounding environment
Give 3 examples of an endothermic reaction
photosynthesis, evaporation, thermal decomposition etc
Give 3 examples of an exothermic reaction
combustion, neutralisation, deposition of dry ice, respiration, solution of sulphuric acid into water, oxidisation, etc
How do we tell whether a reaction is endothermic or exothermic?
We can tell by the temperature change.
The reaction is [endothermic/exothermic] if its temperature has increased.
The reaction is exothermic if its temperature has increased.
The reaction is [exothermic/endothermic] if its temperature has decreased.
The reaction is endothermic if its temperature has decreased.
what do we use to measure energy changes in a reaction?
a calorimeter
Why do we use an insulated cup when measuring energy changes?
To prevent heat loss - to make sure the results are accurate.
Give a brief summary of the method we would use to measure an energy change.
- record the starting temperature
- record the end temperature
- repeat and find the average of both
- calculate- temperature change = start temp - end temp
Define the term ‘activation energy’
The minimum amount of energy reactant particles need in order to collide and react.
in an exothermic reaction, the energy of the products is [more/less] than the energy of the reactants.
in an exothermic reaction, the energy of the products is less than the energy of the reactants.
in an endothermic reaction, the energy of the products is [more/less] than the energy of the reactants.
in an endothermic reaction, the energy of the products is more than the energy of the reactants.
what do neutralisation reactions produce?
a salt + water
stronger acids have a [lower/higher] pH.
stronger acids have a lower pH.
