In this chemical reaction, the magnesium will dissolve in the hydrochloric acid to produce hydrogen gas. This is because magnesium is higher than hydrogen in the reactivity series. Therefore, when the two reactants are combined, a displacement reaction occus and the magnesium displaces the hydrogen, forming magnesium chloride and hydrogen gas.
Mg (s) + 2HCl (aq) -> MgCl 2 (aq) + H 2 (g)
Magnesium + Hydrochloric acid -> Magnesium Chloride + Hydrogen
The aim of this investigation is to observe the effect that the concentration of hydrochloric acid (independent variable) has on the rate of reaction (dependent variable) between the magnesium ribbon and the hydrochloric acid.
As the concentration of hydrochloric acid increases, the time taken for the magnesium to disappear will decrease. (The greater the concentration of hydrochloric acid, the faster the reaction between the magnesium and hydrochloric acid will occur.) In addition, doubling the concentration of hydrochloric acid will halve the time taken for the magnesium ribbon to disappear. This hypothesis is based on the collision theory.
The collision theory states that for a chemical reaction to occur, there is a minimum amount of energy that must be provided by the colliding particles in order to break or form new bonds with other particles. When the bonds are broken this is called a successful collision. If the minimum amount of energy (also known as activation energy) is not provided, the particles will simply bounce off each other causing an unsuccessful collision.
Applying this theory to the hypothesis, a greater concentration would mean there would be more particles in the same volume. A greater amount of particles would result in more collisions, and therefore a higher chance for successful collisions to occur, resulting in a faster chemical reaction since more bonds are being broken. Therefore a higher concentration of