Rates of Reaction Flashcards
What is the effect of temperature on the rate of reaction?
At higher temperatures, a greater proportion of particles have enough activation energy to react, leading to a higher rate of reaction.
This is due to increased kinetic energy resulting in more frequent and successful collisions.
What is the method used to measure the effect of temperature on reaction rate?
- Measure 10cm of HCl and 10cm of sodium thiosulfate in separate clean measuring cylinders.
- Place the conical flask with HCl on the center of the large cross.
- Add sodium thiosulfate to the flask and swirl once to mix, then start the stopwatch.
- Stop the clock when the cross disappears and note the time.
- Repeat the experiment at 4 other temperatures using a water or ice bath.
What controlled variables must be maintained during the experiment?
- Concentration & volume
- Initial temperature
Why may the experiment for effect of temperature on rate of reaction not always be accurate?
The degree of cloudiness is subjective and may vary.
Name one method to improve the reliability of any experiment.
Repeating the experiment
Repeating an experiment helps to ensure consistent results and reduces the impact of anomalies.
What should be done with anomalies in experimental data?
Discard anomalies when calculating the mean
Anomalies can skew results and should be removed for more accurate data analysis.
What is the significance of the temperature in rates of reaction?
Higher temperatures increase the rate of reaction
What is the first step in the method for measuring the reaction of magnesium with hydrochloric acid?
Measure 25cm of 2.0M hydrochloric acid and put it into the beaker.
What happens to the reaction time as the concentration of hydrochloric acid decreases? (Effect of conc. on rate of reaction)
The reaction time increases.
What is the chemical equation for the reaction between magnesium and hydrochloric acid?
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
What is the method for measuring the reaction of marble chips with hydrochloric acid?
Weigh approximately 20g of marble chips, place in boiling tube, add 10cm³ of hydrochloric acid, bung the top, and start the timer. Measure the volume of gas collected every 10 seconds for 2 minutes.
True or False: The size of the marble chips does not affect the volume of gas produced.
False
What are the three sizes of marble chips used in the experiment?
- Small
- Medium
- Large
What is the trend observed in reaction time as the concentration of hydrochloric acid decreases?
The time taken increases and increases faster towards the end.
Which variable is kept constant while changing the concentration of hydrochloric acid?
Volume of hydrochloric acid
What are the control variables in the experiment for effect of surface area?
• temperature
• mass of marble
• concentration & volume of acid
• volume of CO2
How does the size of marble chips affect the rate of gas production?
Smaller chips produce gas faster due to a larger surface area that exposes more particles for collisions with acid.
What is the chemical reaction for calcium carbonate reacting with hydrochloric acid?
CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
What is the method for testing the production of oxygen gas using hydrogen peroxide?
• Add 15cm of Hydrogen Peroxide to 6 test tubes
• Add equal quantities of each possible catalyst to different test tubes
• Look for signs of oxygen gas being produced (effervescence)
This method helps in observing the catalytic effect on the decomposition of hydrogen peroxide.
What is the purpose of a catalyst in a chemical reaction?
Catalysts lower the activation energy and speed up reactions without being used up.
What is the observation used to confirm the production of oxygen gas?
A glowing splint will re-light if oxygen is present.
