Revision Flashcards
How do you calculate the instantaneous rate of reaction at 4.0 minutes
(4 steps)
- Draw a tangent at 4.0 minutes
- Pick two points on the tangent
- Label points
- y2-y1/x2-x1
What type of catalyst is used to speed up the decomposition of hydrogen peroxide?
Heterogeneous
A ball with flames is the warning symbol for what?
Oxidising reagent
An exclamation point is the warning symbol for what?
Irritants
Write a balanced equation for the decomposition of hydrogen peroxide
2H2O2 -> 2H2O + O2
What would you expect to happen if exactly half the concentration of the original hydrogen peroxide solution was used?
The maximum volume would be halved
Define rate of reaction
The change in concentration of one reactant or product per unit time
Describe and explain the change observed in the conical flask during the reaction between sodium thiosulfate and hydrochloric acid
The solution becomes cloudy due to the formation of sulfur
What would be the effect on the reaction times if the experiment were repeated using 0.025 M sodium thiosulfate instead of 0.05M.
Justify your answer
The reaction would be twice as slow because the rate is directly proportional to the thiosulfate concentration
Describe a procedure for diluting 0.20 M sodium thiosulfate to give 50 cm cubed of a 0.12 M solution
Measure 30 cm cubed of the 0.20 M solution and dilute it to 50 cm cubed using deionised water
Why are the concentrations and volume of HCL solution kept constant
So that only one variable is changed
To keep the test fair
Describe the procedure for preparing the 0.08 M solution of sodium thiosulfate from the 0.10M solution
Use pipette to measure 80 cm cubed of 0.1 M solution
Make up with deionised water to 100 cm cubed
Explain why the reciprocal of the time (1/time) may be used as a measure of the initial rate of the reaction
Rate and time are inversely related
