Rates of reaction Flashcards
What is the rate of a chemical reaction
How fast the reactants turn into products
Rate of reaction graphs
-the … the line on the graph the … the … of …
-the lime becomes … steep over … as the … are … up
-the … reactions have the … line and become … in the … time
-the steeper the line on the graph the faster the rate of reaction
-the lime becomes less steep over time as the reactants are used up
-the quickest reactions have the steepest line and become flat in the least time
What must particles collide with enough of to react
Particles must collide with enough energy to react
What does the rate of a chemical reaction depend on
- The … frequency of reacting …, the more … the … the …
- The energy … during a …, particles have to … with enough … for the collision to be …
- The collision frequency of reacting particles, the more collisions the faster the reaction
- The energy transferred during a collision, particles have to collide with enough energy for the collision to be successful
What is the minimum amount of energy that particles need to react called
Activation energy
What 4 things does rate of reaction depend on
- Temperature
- Conc of solution/pressure of gas
- Surface area
- Presence of a catalyst
How does increasing temperature increase the rate of a reaction
-when the … increases the … have more … to move …
-this means they … more …
-the … they move the more … they have so more … will have enough … to make the … happen
-when the temp increases the particles have more energy to move faster
-this means they collide more frequently
-the faster they move the more energy they have so more collisions will have enough energy to make the reaction happen
How does increasing concentration or pressure increase the rate of a reaction
-if a … is more … it means there are more … within a certain …
-this is the same if the … of a … in …
-this makes … more …
-if a solution is more concentrated it means they are more particles within a certain volume
-this is the same if the pressure of a gas in increased
-this makes collisions more frequent
How does increasing the surface area increase the rate of reaction
-by breaking up a … the … area to … ratio …
-this means that for the same … the … will have more … to … with
-so … will be more …
-by breaking up a material the surface area to volume ratio increases
-this means that for the same volume the particles will have more area to collide with
-so collisions will be more frequent
How does using a catalyst increase the rate of a reaction
-a … is a substance that … up a … without be … up in the … itself
-different … are needed for … reactions but they all … the … energy needed for the … to …
-they … an … reaction … with a … activation …
-this means … energy is … for the … to react
-a catalyst is a substance that speeds up a reaction without be used up in the reaction itself
-different catalysts are needed for different reactions but they all decrease the activation energy needed for the reaction to occur
-they provide an alternate reaction pathway with a lower activation energy
-this means less energy is needed for the reactants to react
3 ways to measure the rate of reaction
- precipitation and colour change
- change in mass
- volume of gas given off
Equation for rate of reaction
Rate of reaction =
the amount of product formed OR reactant used / time
How can u use precipitation and colour change to find the rate of reaction
-you can record the … change in a reaction if the … solution is … and the … is a precipitate which … the … (becomes …)
Eg.
-you can observe a … through the … and … how long it takes to …
—>the .. it does, the faster the …
-you can record the visual change in a reaction if the initial solution is transparent and the product is a precipitate which clouds the solution (becomes opaque)
Eg.
-you can observe a mark through the solution and time how long it takes to disappear
—>the quicker it does, the faster the reaction
Issues with using precipitation and colour change to find the rate of reaction
-it’s subjective
-you can’t plot a graph
How can you use change in mass to find the rate of reaction
-you can use a mass …
-as the … is released the … lost is … on the …
-the … the reading on the balance … the faster the …
-if u take … at regular … you can plot a …
-this method is the most …
-you can use a mass balance
-as the gas is released the mass lost is measured on the balance
-the quicker the reading on the balance drops the faster the reaction
-if u take measurements at regular intervals you can plot a graph
-this method is the most accurate
Disadvantages of using change in mass to find the rate of reaction
Gas is released straight into the room
How can u use the volume of gas given off to find the rate of reaction
-u use a … syringe to measure the … of … given off
-the … gas given off during a given time … the … the …
-you can plot a … if you take … at regular …
-u use a gas syringe to measure the volume of gas given off
-the more gas given off during a given time interval the faster the reaction
-you can plot a graph if you take measurements at regular intervals
Change in mass rate of reaction practical
- Add a set … of … HCl to a … flask and place it on a … balance
- Add some … ribbon to the … and quickly … the flask with … wool
- Start the … and record the … on the …
- Take … of the mass at … intervals
- Plot the … in a … and … out the … lost for each reading, then … a graph with … on the x axis and loss of … on the y axis
- … with more … acid solutions
- … variables: v… of a…, a… of m… r…
- Add a set volume of dilute HCl to a conical flask and place it on a mass balance
- Add some magnesium ribbon to the acid and quickly plug the flask with cotton wool
- Start the stopwatch and record the mass on the balance
- Take reading of the mass at regular intervals
- Plot the results in a table and work out the mass lost for each reading, then plot a graph with time on the x axis and loss of mass on the y axis
- Repeat with more concentrated acid solutions
- Control variables: volume of acid, amount of magnesium ribbon
Cloudy precipitate rate of reaction practical
- Add a … volume of … sodium … to a … flask
- Place the flask on a … of paper with a … black … drawn on it
- Add a set … of dilute … to the … and start the …
- Watch the black cross … through the … sulfur and … how long it takes to …
- … this reaction with … HCl …
- … variables: v… of H.. and s… t…
- Add a set volume of dilute sodium to thiosulfate to a conical flask
- Place the flask on a piece of paper with a big black cross drawn on it
- Add a set volume of dilute HCl to the flask and start the stopwatch
- Watch the black cross disappear through the cloudy surfer and time how long it takes to go
- Repeat this reaction with different HCl concentrations
- Control variables: volume of HCl and sodium thiosulfate
How can u calculate the mean reaction rate from a graph
🔺y/🔺x
How do u find the reaction rate at a particular point
-draw a tangent
-🔺y/🔺x
