THE EFFECT OF TEMPERATURE CHANGES ON REACTION RATE

THE EFFECT OF TEMPERATURE CHANGES ON REACTION RATE

Alberto Cánovas and Estefanía Jiménez.

ITRODUCTIONITRODUCTION

The aim of this experiment...

Initially the reaction mixture is purple in colour due to the presence of permanganate ions but it will turn colourless as soon as they are used up. This colour change allows us to follow the course of the reaction.

If the amount of the permanganate ions iniatially present in a series of experiments is the same, then the point at which the purple colour disappears will always represent the same extent of reaction. So if it is the time it take for the colour change to occur then take 1/t as a measure of the reaction rate.

REQUIREMENTS REQUIREMENTS

-DISTILLED WATER-SELECTION OF SYRINGES-BEAKERS-THERMOMETER-ELERMEYER FLASK-HEATER

-OXALIC ACID-SULPHURIC ACID-POTASSIUM PERMANGANATE

Days before, we prepared the solutions!!

The process is always similar, the only thing that changes is the temperature and therefore the reaction rate.

PROCEDUREPROCEDURE

1. Using syringes add 5 cm3 of sulphuric acid, 2cm3 of potassium permanganate solution and 40 cm3 of water to a 100 cm3 dry glass beaker or conical flask.

2. Heat the mixture to about 40ºC,later 50ºC,60ºC and 70ºC.

4. Add the oxalic acid to the mixture in the beaker as soon as possible and at the same time start the timer.

3. When it reaches 40ºC, Place the beaker on a white paper.

5. Gently stir the reaction mixture with the thermometer.

6. When the reaction mixture just turn colourless stop the timer and record the time. Measure and record the temperature of the reaction mixture.

QUESTIONSQUESTIONS

1. State the aim of the experiment.

The aim of experiment is to observe the change of a reaction rate when we increase temperature.

2. State two factors which had to be kept constant in the experiments.

Two factors which had to be kept in the experiments has been the volume and the pressure. 3. How was the rate of the

reaction determined?

The rate of reaction is determined by 1/t.

RESULTSRESULTS

Time (sec) Temperature (ºC)

Reaction rate

126 40ºC 0.0079

66 50ºC 0.015

46 60ºC 0.022

15 70ºC 0.066

CONCLUSIONSCONCLUSIONS

When we increase the temperature, the reaction rate is very fast, but when we decrease the temperature, the reaction rate is very slow.

This lab activity has been a great experience for us!!