Seneca C5 Flashcards
(35 cards)
What are Exothermic Reactions
Energy from the reacting chemicals is transferred to the surroundings, which often increase in temperature as a result
What are examples of Exothermic Reactions
Combustion.
Neutralization.
Oxidation.
What are Endothermic Reactions
Energy from the surroundings is transferred to the reacting chemicals, causing the temperature of the surroundings to decrease
What are examples of Endothermic Reactions
Thermal decomposition.
The reaction that happens when citric acid is combined with sodium hydrogen carbonate (sodium bicarbonate).
What are the 2 main requirements for a successful reaction to take place
. Collisions
. Activation Energy
What is activation energy
The activation energy is the minimum amount of energy that reacting particles must have for a reaction to happen.
What do reaction profiles tell us
. The amount of energy contained within the reactants and the products.
. The activation energy of a reaction.
. The overall energy change that happens as a result of a reaction.
How can catalysts increase reaction rates
. By lowering the activation energy
What is bond energy
All chemical bonds have a “bond energy” that measures the strength of chemical bonds
How can we see if a reaction is exothermic or endothermic (bond energy)
By subtracting the total bond energies of the products from the total bond energies of reactants, we can see if a reaction is endothermic or exothermic
Exothermic reactions (bond energy)
Energy released by making bonds > energy required to break bonds
Endothermic reactions (bond energy)
Energy released by making bonds < energy required to break bonds
Bond breaking
Bond breaking requires energy and thus is an endothermic process
Bond making
Bond making releases energy and thus is an exothermic process
Bond energy
This is a measure of the strength of chemical bonds. The units are kilojoules per mole (kJ/mol)
How do we make a simple cell
We can make a simple cell by connecting 2 different electrodes and putting them in a liquid electrolyte
The difference in the reactivity of the metals produces a voltage
How do we change the voltage output of a cell
. Changing the type of electrode
. Changing the type of electrolyte
. Changing both
Changing the type of electrode
A greater difference in reactivity between the two electrodes will result in the cell having a greater voltage
Changing the type of electrolyte
Changing the electrolyte changes the reactions that happen at the electrodes. This will result in the voltage output of the cell changing.
In a chemical cell, what effect will increasing the difference in reactivity between the two electrodes have on voltage output?
Increasing voltage output
In a chemical cell, what effect will decreasing the difference in reactivity between the two electrodes have on voltage output?
Decreasing voltage output
What is a battery
A battery is a collection of more than one cell joined in series (end-to-end).
How is the voltage of a battery calculated
The voltage of a battery is calculated as the sum of the voltages of its individual cell components.
What happens when the chemicals inside a battery run out
When the chemicals in a battery run out, the battery can not be used anymore.
