Limestone and Building Materials What is limestone?

What do I need to know? Must State that limestone is mainly composed of the compound calcium carbonate, is quarried and can be used as a building material. Should Describe how calcium carbonate can be decomposed by heating to make calcium oxide and carbon dioxide. Could Explain the steps in the limestone cycle.

What is limestone? Limestone is mainly composed of the compound calcium carbonate, We obtain limestone by quarrying It is a useful building material

Problems with quarrying Quarrying is the method that we use to obtain limestone by using explosives to break it into pieces It produces dust which may cause breathing difficulties such as asthma It is noisy It may create more traffic to and from the quarry. Destroys the landscape and may impact wildlife.

Benefits of quarrying Creates local jobs boosting the local economy Provides building materials a valuable raw material for cement

Calcium hydroxide solution The limestone cycle Heat calcium carbonate (limestone) strongly it thermally decomposes to form calcium oxide Calcium carbonate Calcium oxide is another white powder, it reacts exothermically with water to form calcium hydroxide Calcium oxide Calcium hydroxide reacts with more water to form calcium hydroxide solution . Calcium hydroxide Calcium hydroxide solution is known as limewater and is used as a test for carbon dioxide. Calcium hydroxide solution The cloudy substance formed when carbon dioxide is bubbled through limewater is calcium carbonate or limestone.

Step 1 - Heating limestone

Thermal Decomposition Copy and complete this equation. CaCO3  _______ + CO2 Write down the word equation for the process This is the FIRST STEP in the limestone cycle.

CaCO3  CaO + CO2 Calculations of mass This question should be a little bit of revision for you. CaCO3  CaO + CO2 If I heated 100g of calcium carbonate and had 56g of calcium oxide at the end, how much carbon dioxide did I make? Can you explain why?

The second part of the limestone cycle When you react calcium oxide with water it makes calcium hydroxide. The reaction is highly exothermic and produces a lot of heat. The reaction has been used to heat self heating cans of hot drinks. Can you complete the following word equation? Calcium oxide + water  ______________

The third part of the limestone cycle When you blow carbon dioxide into limewater it makes calcium carbonate again. This turns the limewater cloudy. Can you complete the following word equation? Calcium hydroxide + carbon dioxide  __________ + water

Summary State that limestone is mainly composed of the compound calcium carbonate, is quarried and can be used as a building material. Describe how calcium carbonate can be decomposed by heating to make calcium oxide and carbon dioxide. Explain the steps of the limestone cycle

Limestone and Building Materials Other metal carbonates

What do I need to know? Must Recall that when calcium carbonate (limestone) is heated it thermally decomposes. Should Investigate the decomposition of other metal carbonates Could Compare the reactions of different metal carbonates with acids.

Thermal decomposition Test your knowledge: When calcium carbonate is _________ it thermally __________ to produce calcium oxide. Other metal carbonates decompose on heating in a similar way to calcium _________. Metal carbonate  Metal ______ + ________ [heated, oxide, carbonate, decomposes, carbon dioxide]

Word equations Write the word equations for the decomposition of the following carbonates: Magnesium carbonate (MgCO3) Zinc carbonate (ZnCO3) Copper carbonate (CuCO3) If you are confident write the symbol equations too

Check your answers Magnesium carbonate  magnesium oxide + carbon dioxide MgCO3  MgO + CO2 Zinc carbonate  zinc oxide + carbon dioxide ZnCO3  ZnO + CO2 Copper carbonate  copper oxide + carbon dioxide CuCO3  CuO + CO2

Acid rain and metal carbonates Metal carbonates react with acids. The products are carbon dioxide, a salt and water. This means that limestone buildings erode with acid rain.

Test your knowledge Metal _________ react with ____ to produce ______ ______ a salt and water. Limestone is __________ by acid rain. [carbonates, carbon dioxide, damaged, acid] For example: Calcium carbonate + hydrochloric acid  carbon dioxide + calcium chloride + water

Homework In your book: Title: “Building Materials” Find out and write down the composition (make up) of cement, concrete and mortar. Give ONE or more uses for EACH

Summary Must Recall that when calcium carbonate (limestone) is heated it thermally decomposes. Should Investigate the decomposition of other metal carbonates Could Compare the reactions of different metal carbonates with acids.

Limestone and Building Materials Cement, mortar and concrete

What do I need to know? Must State that limestone is heated with clay to make cement Should Explain that mixing cement with sand makes mortar and mixing cement with sand and aggregate makes concrete and uses for each of these Could Describe the problems of producing cement and the effects of smoke particles from the fuel.

Building materials What is the composition of: Cement Mortar Concrete Give a different use for each

Cement, mortar and concrete Cement powder + water = cement Cement powder + water + sand = mortar Cement powder + water + sand + aggregate = concrete

The facts – cement Cement powder + water = cement Strong but brittle May be used for fence posts Usually used as mortar or concrete

The facts – mortar Cement powder + water + sand = mortar Sand makes it flexible. Used as a filler between stone and for pointing Not very strong if hit with a hammer

The facts – concrete Cement powder + water + sand + aggregate = concrete Aggregate makes concrete strong. It can be used as foundations and paving slabs.

Sand content vs. aggregate content The more sand you add to mortar the WEAKER it becomes.

Anomalous results A result which does not follow the expected pattern Clue – work out the difference between each result to determine the odd one out.

Making cement Cement is made by heating calcium carbonate (limestone) in an oven (called a lime kiln) with clay. These are two types of lime kiln

What happens in a lime kiln? Methane gas is burned (like a Bunsen) to heat the limestone This produces CO2 Calcium carbonate thermally decomposes This produces CO2 and calcium oxide Air is blown through to flush out the CO2 and provide oxygen for the methane to burn Nitrogen from the air is unreacted.

Choosing a fuel Burning different fuels at the limekiln may have a number of effects. It may be more efficient It may cost less or be more cost effective However, it may give rise to more dust or particles and this may affect the amount of deposited smoke particles and the health of the local community.

The problem of smoke particles Examination questions frequently examine the use of a different fuel at a cement works (limekiln). It considers in depth the problems of the smoke particles that can be produced. In your answer you need to assess the evidence provided and consider concepts such as: Carrying out an independent scientific study The idea of a fair test Assessing data to determine whether it shows the whole picture. The difference between particle size (measured in mm) and concentration of particles (measured in ppm or parts per million).

Summary Must State that limestone is heated with clay to make cement Should Explain that mixing cement with sand makes mortar and mixing cement with sand and aggregate makes concrete and uses for each of these Could Describe the problems of producing cement and the effects of smoke particles from the fuel.