Svante August Arrhenius

Svante August Arrhenius (1859-1927), born in Vik, Sweden, is often recognised as one of the founding fathers of modern physical chemistry. For his theory of electrolytic dissociation, Arrhenius received the Nobel Prize in chemistry in 1903. Furthermore, it is believed that his most remarkable contribution was his model of the greenhouse effect.

Svante Arrhenius is mainly known for his equation representing the temperature dependence of chemical reaction rates:

k=A exp(-E/RT)

This equation with k being the reaction rate constant, A a pre-exponential factor, E the activation energy, R the gas constant, and T the absolute temperature. Even though, the equation was first formulated by Dutch chemist Jacobus Hendricus van’t Hoff in 1884, Arrhenius supplied the explanation that is still in use today. He believed that the crucial step to receive a chemical reaction was that the collision force of the particles had to be in equilibrium(balanced) and also separated from each other by the activation energy E. Consequently, he explained the temperature dependence of the reaction rate as a change of equilibrium, meaning by increasing temperature, more activated molecules would be able to undergo reaction. Moreover, plotting the experimental results of k against 1/ T (the so-called Arrhenius plot) yielded in many cases a straight line, from the slope of which one could easily calculate the activation energy E {1}. With this equation, scientists are able to calculate the rate of chemical reactions.

To test this hypothesis, I designed an experiment (one similar to the experiment Arrhenius would have done), to find out for myself if this equation was accurate.

Plop Plop Fizz Fizz experiment

Materials:

100ml beaker

4x 1/2 tablet VC

thermometer

Hot & tap water

Stopwatch

Motar and Pestel

Safety:

Goggles and lab coat

Hair tied back

Loose things not hanging out

Procedure:

Establish a control by placing 1/2 of a tablet of VC into 50cm3 of water from the tap, and measure the temperature, and take the time in which the VC takes to dissolve.

Then choose three different independent variables to test.

Write out the steps to follow in order to test your hypothesis in the detailed description, and your prediction.

I chose to test the temperature of water, amount of water/volume, surface area of VC.

3.1-For the experiment in which the temperature of the water was raised, I put 50cm3 of hot water in a beaker, measured the temperature then put the VC in the water and took the reaction time.

3.2-For the experiment in which the amount of water was changed, I decreased the amount of water to 30cm3, measured the temperature, then put the VC in the water and took the reaction time.

3.3-For the experiment in which