Rocks and Building Flashcards
To cover all the Core Chemistry content on Limestone.
One of these diagrams represents an element, one a compound and one a mixture.
Which is which?
The element is b)
(It contains only one type of atom - a red one! - in this diagram the atoms go around in pairs. This is how the gasses Hydrogen, Nitrogen, Oxygen and all the Halogens (F2 to I2) go around ).
The mixture is a)
In this diagram, there are molecules of 2 different elements - a red element and a blue element. (This could represent any of the elements that go around in pairs - as mentioned above. Because the molecules are spread out, these are both gasses)
The compound is c)
This is the only example here of different elements chemically joined together. We can see that the blue and red circles are joined because they are touching. This could represent a gas like carbon monoxide (CO).
What is the chemical formula for limestone?
CaCO3
How many of the following can be made from limestone?
a) Glass b) Iron c) Coal d) Concrete e) Cement f) Mortar
4 of them: Glass, Concrete, Cement and Mortar. Iron and Coal can’t be made from limestone.
Chose the correct answer:
Cement is made by:
a) Heating limestone and clay in a rotary kiln
b) Adding water and aggregate
c) Heating limestone with sand and sodium carbonate
The answer is a) Cement is made by heating limestone and clay in a rotary kiln
When metal carbonates are heated, they break down to form what?
The metal oxide and CO2
Example: CaCO3 ——–> CaO + CO2
Carbonates break down into smaller substances when heated. What is this process called?
Thermal decomposition
What is the chemical name of Quicklime?
Calcium Oxide
What is the chemical name for slaked lime?
Calcium hydroxide
What is the chemical formula of Quicklime?
CaO
What is the chemical name for limestone?
Calcium carbonate
Limewater is a weak solution of Calcium hydroxide (slaked lime).
I bubble a gas through limewater, and it turns cloudy.
Which gas makes limewater turn cloudy?
Carbon dioxide (CO2) makes limewater cloudy. It converts the calcium hydroxide solution back into tiny pieces of calcium carbonate (limestone). These tiny pieces make the solution look cloudy.
What is the chemical formula for slaked lime?
Ca(OH)2
A teacher heats some green copper carbonate in a test tube. After a while it begins to turn black.
A gas is produced which turns limewater cloudy.
What has happened?!!
Thermal decomposition of the copper carbonate (green) has produced copper oxide (black) and carbon dioxide gas. The carbon dioxide gas turned the limewater cloudy.
Limestone is often used without being processed. What is unprocessed limestone used for?
Limestone blocks can be used for building walls and houses. Limestone is sometimes used for flooring (as in the MetroCentre) and for carving statues or even gravestones. In North Yorkshire, where limestone occurs naturally, there are lots of dry stone walls made from limestone.
Limestone is usually obtained by ‘blast’ mining in a quarry.
Can you think of two advantages and two disadvantages of having a limestone quarry near you?
Disadvantages:
Noisy
Dusty
Lots of heavy trucks on the road
An eyesore
Puts off tourists comming to the area.
Advantages:
Creation of jobs in the mine
Creation of work for others (nearby shops etc)
Can create an interesting space afterwards (pond/lake).
When acids react with carbonates what happens? Why is this bad news for St Paul’s Cathedral in London?
The acid reacts with the carbonate to produce a salt, carbon dioxide gas and water. This is bad news for St Paul’s cathedral because rainwater is acidic and the cathedral is built out of limestone blocks. The acidic rainwater reacts with the structure of the Cathedral, slowly eroding it away.
