chemicals in our lives Flashcards
this is done
What are all the different layers of the earth in order of depth. (deepest first)
Inner core
outer core
mantel
crust
how have scientist created an idea of what the world used to look like through fossils and rocks?
fossils of plants and animals found in the rock are distinctive of certain geological time periods. Comparing them against modern day organisms gives an idea of the environment in which they existed
Tectonic plates move due to…
convection currents in the mantle
Coal is formed when…
peat is buried under layers of sediment
Near the Earth’s poles, magnetisation of rocks happens at which angle?
Near the Earth’s poles magnetisation happens at an angle to the horizontal.
what purpose does the mined salt serve?
This method of extraction leaves the salt with insoluble impurities such as reddish clay. This kind of salt is used to put on roads during freezing weather and does not need to be pure.
how is salt extracted from the water? and why do we need to use this alternative method?
when pure salt for industrial purposes is needed a different method is used. Water is forced down a borehole into rock. The salt dissolves making a solution of brine and this solution is withdrawn to the surface and pumped to a purification plant. Water is evaporated from the brine under a range of pressures making the process more efficient. The salt crystallises and is separated from any remaining brine by filtering or using a centrifuge.
What environmental impacts does extracting salt in solution have?
Extracting salt in solution can create large underground caverns. This can lead to bedrock collapsing and as a consequence, cause the lowering of the Earth’s surface. This is known as subsidence. It can be avoided by sensibly spacing out the holes created so the surface is supported by a sufficient amount of rock underground.
what is the Common salt we use called?
Sodium chloride
What is the formula of “common salt”
NaCl
What is the definition of an alkali
An alkali is a compound that dissolves to give a solution with a pH higher than 7. It is also a compound with particular chemical properties including turning litmus blue and neutralizing or effervescing with acids; typically, a caustic or corrosive substance of this kind such as lime or soda.
what are several good uses of an alkali
Converting oils and fats into soap
Making glass
Neutralising acidic soils
Making chemicals that bind natural dyes to cloth.
What was the LeBlanc process, why was it used and what environmental problems did it cause
Due to increased industrialisation in the 1700s there was a shortage of alkali. This led to the need for manufacture on a large scale.
The LeBlanc Process was invented to make alkali sodium carbonate on a large scale. Sodium chloride was mixed with sulfuric acid before being heated with charcoal and limestone.
The process itself was very polluting. It released huge volumes of an acid gas (hydrogen chloride) into the air that wrecked the surrounding land. It also produced large amounts of solid waste that slowly released the toxic gas hydrogen sulfide. This gas has a characteristic smell of rotten eggs.
what is electrolysis?
electrolysis is when an electric current is used to bring about a chemical change and make new chemicals.
Increasing the chain length of a polymer makes it…
Increasing the chain length of a polymer makes it less flexible.
