Rates of Revision Experiments Flashcards
What is an independent variable?
The ONE variable that we will change in our experiment to test its effect on another variable
What is a dependent variable?
The variable we will measure the effect of the independent variable on
Give an example of a dependent variable in this unit
Rate of reaction as measured by the time it takes for the cross to not be visible through teh beaker.
What units are we measuring our dependent variable in?
Seconds, as measured by a stopwatch
Give 4 examples of controlled variables for our assessment experiment?
- .Volume of HCl
- Volume of Sodium thiosulphate
- Person judging and timing when the cross is no longer visible
- Same size beaker (100ml) so depth of solution over cross is same each time
- Temperature - as we know temperature can speed up reactions so we will keep our reactants at the same temperature
What is collision theory?
Collision theory states that for a reaction to occur 2 or more reactant particles must collide with enough energy and at the right orientation.
Draw out a table that you would use to record your data in?
- does it have the independent variable as the first column WITH A TITLE?
- does it have space to collect 3 trials and an average for each level?
- does it have rows for FOUR different levels of your independent variable?
Does it have units your data are in?
What 3 things must your conclusion have in it?
- Link to aim (copied)
- Specific results including the 4 averages and the levels AND a general sentence stating the pattern between your independent variable and the rate of reaction
- Link to your hypothesis (matching the wording you wrote earlier) with whether the data supports it or not.
What are the 2 ways we know our data is reliable?
- We carried out 3 trials for each of our independent variable levels
- We look at our trials within each level to see how similar our results are
Define concentration
The number of particles within a given VOLUME (must include the volume, part not just number of particles)
If the concentration increases what effect does this have on reaction rate?
If concentration increases, we will have an increased rate of reaction as there are more particles for the two reactants to collide with each other.
How would you write a hypothesis (give an eg of wording for temp and reaction rate)
As the temperature of Sodium thiosulphate increases, the rate of reaction with Hydrochloric acid will ….
If I am writing in my method “measured 10ml using a 10ml measuring cylinder” what else must I include following this sentence (hint: HOW do we measure liquids)
Measuring cylinder was on the bench and measurement was taken at eye level to ensure an accurate volume
What must we include in our method regarding trials
That we took 3 trials for each of our levels
How do we calculate concentration in a 100ml cylinder for 80%, 50%, 20%?
80% we fill up our cylinder with 80ml of reactant, 20ml of water
50% we fill up our cylinder with 50ml reactant, 50ml water
20% we fill up our cylinder with 20ml reactant, 80 ml water
