rates of reaction
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What does it mean by “rate of reaction”?
-how fast reactants are changed to products
what are the two ways rate of reaction be calculated? what are the 3 units for rate of reaction?
mean rate of reaction = quantity of reactant used/time taken or mean rate of reaction = quantity of product formed/time taken units= g/s or cm^3/s or (HT ONLY mol/s)
On a graph- what does the gradient of the tangent to the curve show? the steeper the gradient..?
• the gradient of the line is the measure of the rate of reaction. • the steeper the gradient the faster the reaction.
to calculate the rate of reaction at a specific time on a graph- what do you do?
draw a tangent at the point!! and calculate gradient :)
What are the 5 factors that can affect the rate of chemical reactions? -rate your card by how many you get out of five!
• temperature • presence of catalyst • surface area of solid reactants • pressure of reacting gases • concentration of solution
how does temperature affect rate of reaction?
-increasing temperature increases reaction- particles collide more often, particles collide with more energy • temperature increase= more kinetic energy store of particles • more collisions occur- more frequently per second • as they collide with higher energy, there are more effective, successful collisions to make reaction happen
How does surface area affect the rate of chemical reaction?
• increasing surface area = smaller pieces of solid piece • increases surface area to volume ratio • more particles are exposed to reaction • more frequent collisions between reacting particles
How does concentration affect rate of reaction?
-higher concentration = more particles in a given volume -more particles= increases frequency of collisions -effective collisions increase therefore, rate of reaction increase
how does pressure affect rate of reaction?
• higher pressure=same number of particles in a smaller given space • frequency of collisions increased • effective collisions also increase • therefore, rate of reaction increases
how do catalysts affect rate of reaction?
-speed up reaction without being used up • decrease activation energy for a reaction to happen • provide an alternate reaction pathway with lower activation energy • higher proportion of reactant particles have sufficient energy to react • frequency of collisions increases.
activation energy graph with and without catalyst
https://www.google.com/search?q=activation+catalys+graph&tbm=isch&ved=2ahUKEwi6_undt7L4AhVCrhoKHdR1DW4Q2-cCegQIABAA&oq=activation+catalys+graph&gs_lcp=CgNpbWcQAzIICAAQHhAIEAcyCAgAEB4QCBAHMggIABAeEAgQBzIICAAQHhAIEAc6BAgjECc6BggAEB4QCFDuA1ipCmDRDWgAcAB4AIABeIgB_AGSAQMyLjGYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=I2CrYvrgMcLcatTrtfAG&bih=694&biw=1517&rlz=1C1CHBF_en-GBGB893GB893&hl=en-GB
where are catalysts used? advantage + disadvantage?
• in industry • A: increases rates + reduces energy costs • A: helps environment- using lower temperature • D: expensive- buttt cheaper to use catalsyt than pay for extra energy
What is the collision theory?
• chemical reactions can only occur when reacting particles collide with each other with sufficient energy
What is activation energy?
-the minimum amount of energy needed for particles to react
• What to do to make a reaction happen faster? 2. to increase rate of reaction?
1.reduce activation energy • increase frequency of particle collisions increase energy of particles when colliding