Rates Of Reaction Flashcards
What is a catalyst?
A substance which increases the rate of reaction
Chemically unchanged at the end of reaction/not used up
Specific to a reaction - different reactions require different catalysts
How do catalyst increase the rate of reaction?
Lowers the activation energy for the reaction by providing an alternative pathway for the reaction to occur
What happens when you increase the concentration of particles?
The rate of reaction increases - there are more particles in the same volume, so therefore there are more frequent successful collisions between particles
What happens when you increase the surface area of a solid?
The rate of reaction increases - there is a greater surface area where solid particles can collide and there for there are more frequent successful collisions between particles
What happens when you increase the pressure of gas?
The rate of reaction increases - the particles are squashed closer together, so therefore there are more frequent successful collisions between particles
What is the activation energy?
The minimum amount of energy required for particles to collide successfully
What happens when you increase the temperature?
The rate of reaction increases - particles to have more kinetic energy so move around faster and therefore there are more frequent collisions between particles
Describe the experiment that investigates the effect of changing surface area on rate of reaction
- Set up the apparatus. The measuring cylinder should be completely full of water before inverting and the opening kept below the surface of the water in the trough.
- Clamp the measuring cylinder in place.
- Measure 50 cm3 of 0.5 mol/dm3 hydrochloric acid into the conical flask.
- Add 3 g of large marble chips to the conical flask, quickly replace the bung and start the timer.
- Swirling between each reading, record the volume of gas produced every 10 seconds for 210 seconds (3.5 minutes). If the volume of gas exceeds 100 cm3, you should stop taking measurements.
- Pour the contents of the conical flask into a sieve in the sink.
- Repeat the experiment with 3 g of small marble chips.
What chemicals are needed in the experiment that investigates the effect of changing surface area on rate of reaction?
Hydrochloric acid
Small marble chips
Large marble chips
Draw a picture of the set up apparatus for the Surface Area Practical
DONE
Describe the experiment that investigates the effect of changing concentration on rate of reaction
- Set up the apparatus as shown in the diagram. Clamp the gas syringe in place.
- Measure 50 cm3 of 2 mol/dm3 hydrochloric acid into the conical flask.
- Add 3 g of large marble chips to the conical flask, quickly replace the bung and start the timer.
- Swirl frequently.
- In the results table below, record the time taken for 50 cm3 gas to be produced.
- Pour the contents of the conical flask into a sieve in the sink
- Rinse the marble chips with tap water, then shake them dry and return them to your conical flask.
- Repeat the experiment with the same marble chips, but different concentrations of acid (0.5, 0.75, 1, 1.5, 2)
What chemicals are needed in the experiment that investigates the effect of changing concentration on rate of reaction?
Hydrochloric Acid
Large marble chips
Draw a picture of the set up apparatus for the Concentration Practical
DONE
Describe the experiment that investigates the effect of temperature on rate of reaction
- Mark a plastic tub with an X using a permanent marker (~50p sized). Mark a 100 cm3 conical flask with 25cm3 and another with a I0cm3
- Fill with 2cm depth of ice water/ nothing/ hot tap water/ boiled water and put the two conical flasks in.
- Measure 25 cm3of sodium thiosulfate solution using a large measuring cylinder and put it into the conical flask labelled 25cm3.
- Measure 10 cm3 of hydrochloric acid using a small measuring cylinder and put it into the conical flask labelled 10сm3. Allow the solutions a few minutes to reach the same temperature.
- Measure the temperature of one of the solutions then pour one solution into the other.
Immediately start the timer and time how long it takes for the cross to disappear - Wash out the reaction flask thoroughly. Repeat the experiment for the other three temperatures.
What chemicals are needed in the experiment that investigates the effect of temperature on rate of reaction?
Dilute Hydrochloric Acid
Sodium Thiosulfate
Draw a picture of the set up apparatus for the Temperature Practical
DONE
Describe the experiment that investigates the effect of different solids on catalytic decomposition
- In pencil, initial and number (from 1-4) four pieces of clean filter paper then weigh each one.
- Measure 10cm3 of hydrogen peroxide solution into each of four separate boiling tubes.
- Add 0.5g of copper(II) oxide into one of the boiling tubes.
- When the reaction (if any) has stopped, filter your reaction mixture using filter paper 1 and a funnel directly into an empty boiling tube, retaining the residue on the filter paper. Ensure that any solid remaining in the boiling tube is rinsed out and the rinsings poured through the filter paper.
- Leave the filter paper to dry.
- Repeat steps 3-5 with the remaining solids, using the correctly numbered filter paper each time.
- When the filter paper and solids have dried, weigh them and record their mass.
What chemicals are needed in the experiment that investigates the effect of different solids on catalytic decomposition?
Hydrogen peroxide solution
Copper (II) oxide
Manganese (IV) oxide
Copper turnings
Potassium iodide
