C1 Flashcards
what does the nucleus contain?
protons and neutrons
element
substance containing only one type of atom
molecule
2 or more atoms bonded together
compound
Acompoundis a substance formed when two or morechemicalelements are chemically bonded together.
mixture
2 or more atoms/compounds not chemically bomded
where is the lowest energy level?
the shell closest to the nucleus
what is ionic bonding?
Metal + Non-metal
metal loads electrons to form positive ions, non-metal gains electrons to form negative ions
opposite charges attract
what is a covalent bond?
non-metal + non-metal
each atom shares electrons with another ago! to get a full outer shell.
they can form small molecules of giant lattices
describe the limestone cycle
CaCO3 -> CaO -> Ca(OH)2(s) -> Ca(OH)2(aq)
what is produced when limestone thermally decomposes?
Carbon dioxide and Calcium Oxide
what is needed to turn CaO into Ca(OH)2??
water
what is needed to turn calcium hydroxide solution into calcium carbonate??
carbon dioxide
what is limestone used for?
cement, mortar, concrete, Glass, buildings
what are the advantages of quarrying?
- provides jobs
- crater could be used for leisure activities
- money made from products
- can be used as a nature reserve or landfill afterwards
what are the disadvantages of quarrying?
- noise pollution
- huge crater can be seen from miles away
- blasting may scare off wildlife
- lorries are not eco-friendly + wear away at verges
- jobs are not permanent
- quarry costs a lot to set up
limestone is good because:
- limestone is widely available and cheaper than other rock
- hard wearing but still attractive
- doesn’t rot or corrode
metal ore
a rock which contains brought metal to make it economically viable to extract the metal from it
describe reduction with carbon
when an ore is reduced the oxygen is removed
the position of the metal in the reactivity series determines whether it can be extracted by reduction ( must be below carbon)
done in a blast furnace
what is electrolysis
the breaking down of a substance using electricity
metals more reactive than carbon have to be extracted with electrolysis of molten compound
describe the process of electrolysis
The electrolyte is the liquid which conducts the electricity and are often metal salt solutions or molten metal oxides. The electrolyte has free ions which conduct electricity.
electrons are pulled off the metal at the anode causing the metal to go into the solution as ions, the ions are attracted to the cathode where they gain electrons and turn back into metal atoms. impurities are dropped at the anode as sludge.
What is the overall charge on an atom?
neutral (0)
What is the charge of a proton?
+1
What is the charge of a neutron?
0
What is the charge of a electron?
-1
What is the relative mass of a proton?
1
What is the relative mass of a neutron?
1
What is the relative mass of a electron?
negligible (1/1840)
What does the atomic number tell you on the periodic table?
how many protons it has (and also how many electrons)
What does the mass number tell you in the periodic table?
how many protons + neutrons
What is thermal decomposition?
breaking down a chemical using heat
What is calcium hydroxide used for?
neutralisation. it is an alkali.
e. g. farmers might use it on fields to neutralise soil
how do you test for carbon dioxide?
bubble it through limewater, if it goes cloudy it is CO2
What is cement made from?
heated limestone and clay
What is concrete made from?
cement, sand and aggregate (rocks/stones)
what is mortar made from?
cement and sand
Why does gold stay shiney for a longer time than copper?
gold is less reactive
What is phytomining?
phytomining uses plants to absorb metal compounds and that the plants are burned to produce ash that contains the metal compounds
what is bioleaching?
bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
why is it expensive to remove aluminium and titanium from their ores?
there are many stages in the processes and large amounts of energy are needed.
why is recycling metals a good idea?
- extracting them uses limited resources
- it is expensive in terms of energy and effects on the environment to extract new ores
what is steel?
Steels are alloys since they are mixtures of iron with carbon. Some steels contain other metals.
What is an alloy?
a mixture of metals
Low carbon steel
has 0.1% carbon
Low-carbon steels are easily shaped
used for car bodies
why are gold, copper and aluminium often made into alloys?
Pure copper, gold, iron and aluminium are too soft for many uses and so are mixed with small amounts of similar metals to make them harder for everyday use.
what is copper useful for?
Copper has properties that make it useful for electrical wiring and plumbing. is a good conductor of electricity and heat
can be bent but is hard enough to be used to make pipes or tanks
does not react with water.
why are aluminium and titanium very useful?
Low density and resistance to corrosion make aluminium and titanium useful metals.