How Does The Concentration Of Hydrochloric Acid Affect The Rate Of Reaction

Thousands of chemical reactions occur in every day life, at different rates and different times. Whether it be washing the dishes after dinner or brushing your teeth in the morning, they all have one thing in common; a chemical process in which reactants act mutually on each other to form a new substance.

Rate of reaction is the term used to describe how quickly reactants turn into products. According to collision theory, proposed by Max Trautz and further added to by William Lewis in 1918, for a reaction to take place the colliding molecules must possess enough kinetic energy, this is called the activation energy, allowing the reactants to chemically bond. Activation energy is the minimum energy required for a reaction to occur. Also, as

Hydrochloric acid is a chemical used in the process of digestion and is a vital to our ongoing health and well being. The concentration of hydrochloric acid in the stomach is approximately 0.05 – 0.1 moles/litre (M). However hydrochloric acid at 18% is used in many industrial processes and has the capacity to melt steal.

Aim
The purpose of this experiment is to investigate how altering the concentration of hydrochloric acid, when reacting with sodium thiosulfate, can change the rate of a reaction.

Hypothesis
If three beakers are filled with sodium thiosulfate and differing concentration levels of hydrochloric acid then, the rate of reaction will occur quicker using a higher concentration of hydrochloric acid. This is because an increased concentration means there are more reactants which leads to more successful collisions in a set time period. Therefore, reactants with a higher concentration will have a faster rate of reaction and the cross will disappear

The concept states that reactions take place through the collisions of particles. However, for a collision to be a success and the reaction occur, the colliding particles must have sufficient energy to surpass the required activation energy. The theory states that the molecules must collide at the correct orientation and for the collision to be a success. This principal explains how only a fraction of collisions that take place are successful. The percentage of successful collisions may increase or decrease depending on the circumstances of the collisions.

Collision theory, proposed by Max Trautz and further added to by William Lewis in 1918, is proven in the results. The greater concentration, or particles in a substance, increases the risk of collisions in a set time. However only a proportion of collisions result in successful chemical bonding. The increased number of particles leads to more collisions and increases the rate of successful collisions and therefore consequently decreasing the rate of