Research question: Will the level of acidity of the rain have an effect on the corrosion of limestone, as measured by change in mass of marble chips in a beaker?
Introduction: Acid rain is any form of precipitation due to excess or elevated levels of hydrogen ions. It is also a process by which acid particles leave the atmosphere. Natural rain has a pH of 5.6; this is due to the presence of carbonic acid by the mixture of carbon dioxide dissolved in water in the atmosphere.
H2O + CO2 → H2CO3
The carbonic acid molecules immediately dissociate in water to form hydrogen carbonate ions:
HCO3−, and hydronium ions, H3O+: H2CO3 + H2O → HCO3− + H3O+
The deposition of acid like sulfuric and sulfurous make rain water acidic this is from the sulfur
…show more content…
Hypothesis: Limestone and marbles are forms of calcium carbonate. They are used in many historical buildings as building material. Acids such as H2SO4 directly attack and erode these materials. I predict that at higher pH the marble chips will be lose more mass than at lower pH as the stronger the acid the more the calcium carbonate is being …show more content…
Controlled Variable How it Was Controlled Why It Was Controlled
Source of Marble Chips The same slab of marble was used for every sample of marble chip. Different type of marble will affect the rate of corrosion hence giving us different values of change in mass.
Mass of Marble Chips Every sample was measured on a scale to match the weight. Difference in the mass of the samples will also affect values, as the corrosion rate will vary.
Volume of acidic solution Volume of the water was measured in a graduated cylinder. More acidic solution will result in higher rates of corrosion and vice versa
Time in acidic solution A stopwatch was used to measure the amount of time each sample was kept in the solution The amount of corrosion will increase as the sample is kept in the solution for longer periods of time.
Temperature of Room The temperature of the AC was regulated to be constant. The temperature can affect the rate of the reaction, which in turn will affect the experiment.
Procedure:
• Cut each sample of marble sample must be cut into equal pieces and must be then measured to match a weight of 50g in the weighing