Effect of Concentration on the Rates of Reaction Between Hydrochloric Acid and Marble Chips

Effect of Concentration on the Rates of Reaction Between Hydrochloric Acid and Marble Chips

Aim;

To investigate how changing the concentration of Hydrochloric Acid

affects the Rate of Reaction of producing 20cm³ of Carbon Dioxide with

Marble Chips.

HCl +calcium carbonate => calcium chloride + carbon dioxide + water.

HCl (aq) +CaCO3(s) => CaCl2 (aq) +CO2 (g) +H2O (l)

Theory;

All substances are made up of millions of particles. These particles

may be atoms, molecules or ions. For a reaction to take place, the

particles of the substances that are reacting have to collide. If they

collide, with enough energy, then they will react. The minimum amount

of kinetic energy that two particles need if they are going to react

when they collide is called the activation energy.

The rate of reaction is the speed of the reaction. It is not "how

much" of a product is made, but "how quickly" a reaction takes place.

We can measure the rate of a reaction by measuring how quickly one of

the products is made, or measure how quickly one of the reactants

disappears. In this experiment, we saw how quickly one of the products

- carbon dioxide - is made.

Four things affect the rate of a reaction; concentration, surface

area, temperature and the use of a catalyst. Within this experiment I

looked at concentration and surface area - although temperature may

have still played a part in the final results.

The concentration of a solution is how strong the solution is. In this

experiment, the stronger acid contains more acid particles and less

water particles than a weaker acid. Increasing the concentration of

the solution leads to more collisions so the rate of the reaction goes

up. In a less concentrated solution (diluted hydrochloric acid), the

number of collisions is long so the rate of reaction is slower. With a

more concentrated acid, the number of acid particles is greater, so

the number of collisions is greater, and the rate of reaction is

faster.

Solids with a smaller particle size react more quickly than solids