The Effects of Acid Rain on Statues

The Effects of Acid Rain on Statues

Introduction

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During this investigation, I will use dilute hydrochloric acid as the

acid rain and crushed calcium carbonate as the chemical of the

statues. Then I will time how long it takes for the limestone powder

to react until there is no more left when the acid is added to it.

Rain contains acid naturally as it collects carbon dioxide from the

air and makes carbonic acid. Rain normally has a pH of about 5.5 – it

is slightly acidic due to the carbon dioxide dissolved in it. It is a

stronger acid if gases like sulphur dioxide and nitrogen oxides escape

into the air from the burning fossil fuels, because they are dissolved

by the rain and produce sulphuric and nitric acids that does more

damage in a faster time. Acid rain reacts with statues and buildings

that contain calcium carbonate and form carbon dioxide and water.

The dilute hydrochloric acid in this investigation will have the same

effect on the limestone as the acid rain on the statues. Yet, the

only difference is that in nature, the acid rain reacted with the

statue as a whole body, which takes approximately hundred years to

corrode the object, whereas the hydrochloric acid in this

investigation will take only few seconds to react with the limestone

powder.

Planning

Aim

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The aim of my experiment is to investigate if the speed at which the

limestones are dissolved is changed by how concentrated the acid is.

Equipment

To do my experiment, I will need beakers, a paper spoon, a stop clock,

limestone powders, stirring rod, measuring cylinders and an electronic

balance for powders

Plan

For this experiment, I will use 30mls of the acid each time and 1gm of

powdered calcium carbonate. The concentration of the acid will be

changed by adding water and less acid each time.

First, I will use a paper spoon to spoon out the limestone powder and

weigh it on the electronic balance. Next, take out the excess powder

until the weight is 1gm. Then use two measuring cylinders, with each

measuring the amount of water and dilute hydrochloric acid that should

be added, e.g. when there is 30mls of acid, 0mls of water will be

added; when there is 25mls of acid, 5mls of water will be added, and

so on. The total amount will always be 30mls. Afterwards, I will pour

the powder into a beaker that contain correct amount of acid in it and

use a stop clock to time how long it will take for the powder to

disappear. A stirring rod will be used so that no lumps would form.