INTRODUCTION

• INITALLY THE REACTION MIXTURE IS PURPLE, BUT IT WILL TURN COLOURLESS.

• 5(COOH)2 + 6H + 2Mno4 2Mn2 + 10CO2 + 8H2O

• Oxalic acid reacts with acidified solution of potassium permanganate.

REQUIREMENTS

• 100 ml erlenmeyer • 600 ml beaker • Timer• Heater• Thermometer• Deionised water• 3 syringes• gloves

• 0.2 M oxalic acid• 1M sulphuric acid• 0,02 M potassium permanganate

PROCEDURE• Using syringes add:• 5 cm3 of sulphuric

acid, • 2 cm3 of potassium

permanganate solution

• 40cm3 of water to a 100cm3 dry erlenmeyer.

• Heat the mixture to about 40ºC.

• Place the beaker on a white paper

• When the mixture is over 40ºC, add 1 ml of oxalic acid and remove from the heat.

• After the reaction mixture turns colourless, stop the timer and record the time.

• REPEAT THIS PROCEDURE THREE TIMES AT: 50ºC, 60ºC AND 70ºC.

TABLE

DEGREES TIME(seconds)

40ºC 348

50ºC 236

60ºC 148

70ºC 51

0

0,005

0,01

0,015

0,02

0 50 100

TEMPERATURE

1/t Serie1

QUESTIONS• State the aim of the experiment.

- The aim of the experiment is to observe the effect of temperature changes on reaction rate

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

- Two factors which had to be kept constant were volume and pressure.

• How was the rate of the reaction determined?

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

SARA PÉREZ BONILLA AND IRENE MUÑOZ