C1 Flashcards
Using the periodic table how can you work out the number of shells an element has?
The number of rows down the element is = the number of shells
Using the periodic table how can you work out the number of electrons an element has in it’s outer shell?
The number of electrons in the outer shell = the column number
Where is a proton in an atom? How much does it weigh? What is their charge?
How do you calculate the number of protons in an atom?
In the nucleus.
1
+1
The atomic number
Where is a neutron in an atom?
How much does it weigh?
What is their charge?
How do you calculate the number of neutrons in an atom?
In the nucleus
1
0
The mass number minus the atomic number
What is the charge of a nucleus?
Positive
Where is an electron in an atom?
How much does it weigh?
What is their charge?
Orbits the nucleus, occupies shells
Almost 0
-1
What charge does an atom have? Why?
Neutral. The electrons cancel out the positive charge
How do you make an Ion?
An Ion is a charged particle that has had an electron added or removed
What is a compound?
A substance of two + elements that are chemically bonded. Once bonded it becomes difficult to separate the two original elements
Name two different types of compounds and which types of elements they occur between?
Ionic - a metal and a non-metal
Covalent - a non-metal and a non-metal
In an Ionic bond what are the charges of the parts?
The metal ion loses a electron to become positive. The non metal gains an electron and becomes negative. Opposites attract.
Balance this equation…
H(2)SO(4) + NaOH –> Na(2)SO(4) + H(2)O
H(2)SO(4) + 2NaOH –> Na(2)SO(4) + 2H(2)O
What is the chemical symbol for limestone?
CaCO(3) Also known as calcium carbonate.
What happens to limestone when it’s heated?
Whats the equation?
It thermally decomposes and forms calcium oxide, also known as quick lime & carbon dioxide
CaCO(3)[s] –> CaO[s] +CO(2)[g]
What is CaO?
calcium oxide/quick lime
Calcium oxide reacts with water to form…
What is the equation?
Calcium hydroxide/slaked lime
CaO + H(2)O –> Ca(OH)(2)
What is Ca(OH)(2)?
Calcium hydroxide/slaked lime
What is carbon hydroxide used for?
It’s an alkali that is used to neturalise acidic soil.
How can you test for Carbon dioxide?
Bubble the gas through limestone which will turn cloudy if there’s carbon dioxide present.
What happens when you add Carbon Dioxide to Carbon hydroxide?
It forms calcium carbonate (limestone) and water.
A metal carbonate reacts with acid to make…
…A salt, carbon dioxide and water
What is Thermal decomposition?
When a substance is heated and chemically changes into 2+ substances
How do you make cement?
Crushed limestone + powered clay heated in a kiln at 1450°c + calcium sulfate
What is Mortar made of?
What is Concrete made of?
Mortar; Cement, sand + water
Concrete; Cement, aggregate (gravel + water)
Name the advantages (5) of using Concrete when building…
1) Concrete is strong when squashed.
2) You can custom mould it when wet
3) It’s cheap and quick
4) It won’t rot (like wood) or corrode (like metal)
5) It’s fire resistant
1) It is Ugly
2) low tensile strength; cracks if bent or stretched
Name four disadvantages of quarries?
1) Quarries are unsightly
2) Cause noise pollution (explosives)
3) Quarries destroy habitats
4) Exhaust fumes from the Lorries contribute to the Green house effect
Three advantages of quarries?
1) Creates jobs for people bringing money into the economy
2) It provides building materials
3) After the quarry is used, they usually are made into nature reserves
What are the advantages of using limestone as a building material?
Cheap and hard wearing but i eroded by acid rain
Name the disadvantages of cement…
Making process creates lots of dust which causes breathing problems. The energy used to produce it usually comes from fossil fuels; pollution
You can make concrete stronger by…
You can make concrete stronger by reinforcing it with steel.
What are the uses of Limestone?
1) A building material.
2) Powdered limestone is used neutralize acidic soil (slower than calcium hydroxide)
3) When manufacturing cement, glass & iron
4) To produce calcium oxide (quick lime)
What is an ore?
A rock that contains metal-compound
What is aluminium ore?
Bauxite
Why would you need to chemical reactions to extract metals?
Unreactive metals like gold are found in the Earth as the metal itself but most metals are found as compounds so need a chemical reaction to extract the metal.
What can be used to extract a metal less reactive than carbon?
Metals less reactive than carbon can be extracted from their oxides by reduction with carbon. Carbon can only remove oxygen from metals which are less reactive than itself.
What happens in reduction?
When a ore is reduced Oxygen is removed, this happens in a blast furnace (smelting).
1) When would you use electrolysis?
2) What are 2 examples of metals that are extracted with electrolysis?
1) For a metal more reactive than carbon.
2) aluminium and copper
1) What is electrolysis?
2) What is an electrolyte?
1) It is the breaking down of substances using electricity
2) Either metal salt solution made from the ore or a molten metal oxide. An electrolye contains free ions which conduct the electricity and are key.
What happens in electrolysis?
1) A negative electrode (aka. cathode) and a positive electrode (aka. anode) are placed in a solution and a current is passed through.
2) The solution is either an ionic molten metal oxide or an ionic metal salt solution, this means it is made up of a negatively charged part and a positively charged part.
3) The current causes the electrons to leave the anode and go to the cathode (This is the end of the circuit).
4) The positive metal ions are attracted to the cathode. At the cathode an electron is given to the ion causing it to become a pure metal atom. (if something gains an electron it becomes negative-this cancels the positivity of the metal ion)
5) The negative non metal ions are attracted to the anode where electrons are pulled off by the anode.
1) What would be the 1/2 equation for copper in a copper chloride solution at the cathode?
2) anode?
1) Cu2+ + 2e- –> Cu
2) 2Cl- –> Cl2+ + 2e-
Copper extracted by reduction with carbon in a furnace (smelting) is impure.
How do you purify it? Why?
Electrolysis, pure copper is a better conductor
How does displacement work?
If you put a reactive metal into a solution of a dissolved metal the reactive metal will replace the less reactive metal in the compound, this is because the more reactive metal bonds more strongly to the non metal compounds displacing the less reactive metal .
How would you use displacement to extract copper?
Positives? Negatives?
Scrap iron (cheap) is put in a copper sulfate solution, the iron is more reactive so displaces the less reactive copper from the solution. An equation for this particular displacement will go cooper sulfate + iron --> iron sulfate + copper. The metal must be MORE reactive than the metal (copper) in the solution
+ cheap; scrap metal
- Takes a long time
What does the short supply of copper ores mean?
There may be shortages in the future because of the demand.
We need to recycle copper
What Is bioleaching?
Positives? Negatives?
Bacteria get energy from the bond between copper and copper sulfide, this separates the metal and ore, produce a leachate solution containing copper which can be filtered out.
+ Easy
+ No emissions
-slow (compared to smelting)
What is phytomining?
Positives? Negatives?
Planting on low grade copper ores, plants absorb copper but can’t use/get rid of copper so it builds up in leaves. The plants can then be harvest and burned creating a copper rich ash
+ cost effecive
- Air pollution
- Takes a long time
Electrolysis;
Positives? Negatives?
+ Fast
- Uses lots of electricity; expensive
Name positives of metal extraction.
Name negatives of metal extraction.
+ Useful products metal)
+ Provides people with jobs
+ Brings money into the area (improve transport and other services)
- Bad for the environment
- Scars landscape
- Loss of habitats
- Mine shafts are danger (fall through)
- Uses lots of energy (comes from burning fossil fuels)
Why should we recycle metals?
Recycling metals uses a small fraction of the energy need to mine and extract them;
Less fossils fuels are used (which are bad for the environment)
It’s cheaper as energy is expensive.
Conserves the finite resources of metal.
Cuts down on landfill (takes up space & pollutes surroundings)
1) Name 2 properties of metals.
2) What are metals useful for?
#1 Strong (can still be hammered/bent into shapes) #2 Good conductors of heat and electricity
2) Structural materials or for making things that must allow heat or electricity to pass through them easily.
What is metal fatigue?
When stresses/strains are placed on metals they become ‘tired’ and break
What are the properties of copper?
Uses?
#1 Good conductor of electricity #2 Hard and strong #3 Malleable #4 Doesn't react with water
Plumbing, copper pans, moulds, coins and electricity
What are the properties of aluminium?`
Why is it expensive?
Uses
#1 Corrosion resistant #2 Strong #2 Low density It is expensive because it uses lots of electricity (electrolysis) Aeroplanes
What are the properties of titanium?
Uses?
#1 Low density #2 Very strong #3 Corrosion resistant
Replacement hips
What is cast iron?
Impure iron straight from the blast furnace, it is very brittle.
Why are pure metals malleable?
The atoms sit in a regular arrangements so easily slide over each other.
What is steel?
A compound of iron,carbon (sometimes other metals as well)
Low carbon steel;
What percentage is carbon?
What are it’s properties
What are it’s uses?
DOUBLE CHECK
1) 0.1%
2) Easily shaped
3) car bodies, food cans
High carbon steel;
What percentage is carbon?
What are it’s properties
What are it’s uses?
DOUBLE CHECK
1) 1.5 %
2) Very hard, inflexible
3) Construction, bridges, cutting tools
Stainless steel;
What is added?
What are it’s properties
What are it’s uses?
1) chromium (sometimes nickel)
2) Corrosion resistant
3) Cutlery, surgical instruments, kitchen sinks
