Investigating the Effect of Acid Concentration on Marble Chips

Investigating the Effect of Acid Concentration on Marble Chips

Planning:

The aim of this practical is to investigate the effect of varying acid

concentrations on marble chips (CaCO3)

2HCL + CaCO3 à CaCl2 + CO2 + H20

Hydrochloric Acid + Calcium Carbonate à Calcium Chloride + Carbon

Dioxide + Water

Increasing the concentration of an acid increases the number of

collisions between particles, therefore, the rate of reaction

increases.

The reaction will start faster in comparison to the speed at the end

of the reaction. This is because when the two reactants are first

mixed, their concentrations are both at their highest. As the

experiment goes on, the concentration of the reactants will slow down,

so the reaction will slow down until it finally comes to a stop.

Constants:

o The size of the marble chips - all the marble chips used will be 6mm

in length. This is because the surface area of the substance affects

the rate at which the reaction takes place. A larger surface area

means the reaction goes more quickly, so I need to keep the size of

the chips equal so as to make it a fair test.

o The mass of marble chips - obviously, if the total mass of the

marble chips is varied, the reaction will not be a fair test, so I

must keep the mass the same. By using the above methods, the amount

will be kept the same

o Volume of acid - although the amount of hydrochloric acid needed to

neutralise the marble chips differs according to the strength of the

acid, the volume must be kept the same so as to make it a fair test.

In order that the acid should not run out on the weakest concentration

of acid, the volume will be 200cm3, which is enough to accommodate all

of the concentrations.

o The apparatus that I use will be kept constant throughout the

experiment so that it is a fair test.

o The surrounding conditions - Air humidity, Temperature, Pressure.