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17 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Define "rate of reaction" and state its units. |
A measure of how fast the reactants are used up or how fast the products are formed. (Units = moldm-³s-¹) |
Reactants and products |
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How can you increase the rate of a reaction? |
•increase concentration of reactants •increase temperature •addition of a catalyst (lowers activation energy •increase surface area (to expose more particles) •increase pressure (gases only!) |
C C P T S |
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Define "activation energy" |
Minimum energy required for a reaction to take place |
Minimum |
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How does increasing concentration affect the rate of reaction and why? |
•more moles in same amount of space •increases total number of collisions •increases the chance (and rate) of successful collisions |
Moles, success |
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How does increasing the pressure affect the rate of reaction? |
•decreases volume •particles pushed closer together •raises collision frequency •increases chance of successful collisions |
Volume |
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What does the area under the Boltzmann distribution curve represent? |
Total number of molecules |
Molecules |
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The curve never touched the x-axis on the Boltzmann curve because... |
There is no maximum energy for a molecule |
Energy |
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The curve must start at the origin because... |
There are no molecules with zero energy (they always have some degree of movement/vibration) |
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When temperature increases, how does it affect the Boltzmann curve and why? |
The peak of the curve goes lower and moves to the right hand side because the number of molecules with enough energy to react is increased |
Activation energy |
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What happens to the area under the Boltzmann curve if temperature increases? Explain. |
Nothing, it stays the same because there is still the same amount of molecules. Just the average energy possessed by molecules is now higher. |
E ≥ Ea |
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Define "catalyst" |
A substance that increases rate of reaction without being used up in the process |
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Why might some activation energies be very high? |
If very strong bonds or a large number of bonds have to be broken |
Bonds |
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Homogeneous catalyst is... |
In the same state as the reactants |
Homo |
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Heterogeneous catalyst is.... |
In a different physical state as the reactants |
Hetero |
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Carboxylic acid + alcohol -> RCOOH + R'OH -H+-> |
Ester + water RCOOR' + H2O |
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Alkene + water -> CH2=CH2 + H2O -H+-> |
Alcohol CH3CH2OH |
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Why do catalysts reduce our demand for fossil fuels? |
If a chemical process can run at a lower temperature but at the same efficiency when a catalyst is present, then the demand for energy is lower, meaning less fossil fuels were burnt to run the process |
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