Rates Of Reaction Flashcards
How can the rate of a reaction be calculated?
1
—
t
What are the units for rate of reaction
s (to the power of) -1
How would you investigate the effect of temperature on the rate of reaction using a gas syringe?
Measure out 0.4g of calcium carbonate chips on a weighing boat.
Measure out 50cm3 of hydrochloric acid of a certain temperature (room temperature or 50C in a water bath or from an ice bath).
Place this in the conical flask.
Add the carbonate to the acid and replace bung quickly.
Start your stop watch and measure the volume of gas every 0.5 minutes for 5 minutes. Record all your results.
Repeat for one other temperature of acid.
How would measure the change in mass over a period of time to see how changing the surface area of marble chips affects rate of reaction?
Measure out 50cm3 of hydrochloric acid (2mol/dm3) using a measuring cylinder and pour into conical flask.
Measure out 6g of large marble chips.
Place the conical flask on the balance and record the mass.
Add the marble chips to the acid and plug the top of the conical flask loosely with cotton.
Record the mass reading every minute until there is no change in mass for at least 2 minutes.
Repeat previous steps but with 6g of small marble chips.
How would you measure the amount of time it takes for a certain amount of precipitate to form?
Pour exactly 10cm3 of sodium thiosulfate solution into a 100cm3 measuring cylinder, and then add exactly 40cm3 to the same cylinder.
Pour exactly 5cm3 of hydrochloric acid solution into a 10cm3 measuring cylinder.
Draw a small cross on the piece of paper and place a 100cm3 conical flask on top. Pour the sodium thiosulfate solution into the flask.
Pour the acid into the conical flask and start the clock.
Time the amount of time it takes for the cross to disappear when viewed through the depth of the solution. Record this in a results table.
Rinse apparatus and repeat the experiment four more times at different concentrations of sodium thiosulfate solutions.
Calculate the rate of reaction for each solution using 1/t
What is the independent variable?
Factor you change
What is the dependent variable
Factor you measure
How should a graph be plotted?
Include all labels and title
Put the dependant variable on the y axis and the independent on the x
Include a line of best fit.
What is a successful collision?
When reactant particles collide with the activation energy, resulting in a reaction.
What is an unsuccessful collision?
When particles collide with less than the activation energy and no reaction takes place
What is activation energy?
The minimum energy required for a reaction to occur.
How does the number of successful collisions affect the rate of reaction?
More successful collisions = faster rate of reaction
Why is rate of reaction important in the chemical industry?
Chemists are involved in making many important commercial products, and want reactions to be as fast as possible so they can make more of these products faster.
What factors affect rate of reaction?
Concentration, surface area, temperature, catalysts?
How does concentration affect rate of reaction?
Number of particles increase
More collisions
More successful collisions per unit time
-> increased rate of reaction
