Question

Мемориальный ансамбль Братского кладбища изготовлен из известкового туфа, который представляет собой пресноводную известь (горную породу, в состав которой входит карбонат кальция). Со временем кислотные осадки ощутимо попортили поверхность известкового туфа.А) Поясни, почему кислотные осадки могли повредить поверхность известкового туфа.Б) Свой ответ проиллюстрируй уравнением соответствующей химической реакции.Ц) Напиши, как можно было бы экспериментально проверить это предположение, если бы в твоем расположении был кусочек известкового туфа. Д) Укажи необходимые для проведения данного эксперимента вещества и принадлежности .

Answer 1

Кислотные осадки - это очень разбавленные кислоты (HNO3, HNO2, H2SO3) - эти кислоты разрушают карбонаты (химическое выветривание)
б) CaCO3 + 2HNO3 = Ca(NO3)2 + H2O + CO2
CaCO3 + 2HNO2 = Ca(NO2)2 + H2O + CO2
CaCO3 + H2SO3 = CaSO3 + H2O + CO2
CaCO3 + 2H2SO3 = Ca(HSO3)2
c) я бы подействовал на него соляной кислотой
СаСO3 + 2HCl = CaCl2 + H2O + CO2
д) известковый туф кусочек, химический стакан, соляная кислота.

Answer 2

The Effect of Acidic Deposits on the Surface of Limestone Tuff

The Bratsk Cemetery Memorial Ensemble is made of limestone tuff, a type of sedimentary rock composed mainly of calcium carbonate. Over time, acidic deposits can significantly damage the surface of limestone tuff. Let's explore why acidic deposits can harm the surface of limestone tuff, illustrate the corresponding chemical reaction, and discuss how this hypothesis could be experimentally tested.

A) Explanation of the Damage Caused by Acidic Deposits

Acidic deposits, such as acid rain or acid fog, contain high concentrations of acidic substances like sulfur dioxide (SO2) and nitrogen oxides (NOx). When these acidic substances come into contact with limestone tuff, a chemical reaction occurs. The acid reacts with the calcium carbonate (CaCO3) in the limestone tuff, leading to the formation of soluble calcium salts, such as calcium sulfate (CaSO4) and calcium nitrate (Ca(NO3)2). This reaction is known as acid dissolution or acid erosion.

The chemical equation for the reaction between acid and calcium carbonate is as follows:

CaCO3 + H2SO4 → CaSO4 + H2O + CO2

In this reaction, sulfuric acid (H2SO4) reacts with calcium carbonate (CaCO3) to produce calcium sulfate (CaSO4), water (H2O), and carbon dioxide (CO2). The carbon dioxide is released as a gas, while the calcium sulfate dissolves in water, leaving the surface of the limestone tuff damaged.

B) Illustration of the Chemical Reaction

The chemical reaction between sulfuric acid and calcium carbonate can be represented by the following equation:

CaCO3 + H2SO4 → CaSO4 + H2O + CO2

This equation shows that one molecule of calcium carbonate reacts with one molecule of sulfuric acid to produce one molecule of calcium sulfate, one molecule of water, and one molecule of carbon dioxide.

C) Experimental Verification

To experimentally verify the hypothesis that acidic deposits can damage the surface of limestone tuff, one could perform the following experiment:

1. Obtain a small sample of limestone tuff from the Bratsk Cemetery Memorial Ensemble. 2. Prepare a solution of known concentration of sulfuric acid (H2SO4). 3. Immerse the limestone tuff sample in the sulfuric acid solution for a specific period. 4. After the designated time, remove the limestone tuff sample from the solution and observe its surface for any signs of damage or dissolution. 5. Compare the appearance of the limestone tuff sample before and after the experiment to determine if there is any visible change.

D) Required Substances and Equipment

To conduct this experiment, the following substances and equipment would be necessary:

1. Limestone tuff sample (obtained from the Bratsk Cemetery Memorial Ensemble) 2. Sulfuric acid (H2SO4) solution of known concentration 3. Beakers or containers for holding the sulfuric acid solution 4. Gloves and safety goggles for personal protection 5. Stirring rod or tongs for handling the limestone tuff sample 6. Water for rinsing the limestone tuff sample after the experiment 7. A scale or balance to measure the mass of the limestone tuff sample before and after the experiment (optional)

By conducting this experiment, one can observe the effects of sulfuric acid on the surface of limestone tuff and verify the hypothesis that acidic deposits can damage the material.