- Protons have a mass of 1 and charge of +1, Electrons have mass of almost 0 and charge of -1 and Neutrons have a mass of 1 and a charge of 0.
- Electronic configuration is the number of electrons in each shell e.g. Argon = 2,8,8
- Covalent bonding is when a non-metal and non-metal bond together.
- Ionic bonding is when a metal and non-metal transfer electrons to make ions then opposites attract.
- Metalic bonding is when two metals bond together.
- Bonding of sodium and chloride is ionic bonding. Sodium loses one electron and becomes a positive ion, chloride gains that electron and become negatively charged. The two oppositely charged ions are attracted to each other and chemically bond.
- The periodic table tells us about how many protons, neutrons and electrons in every element. They are in groups according to how many electrons are on their outer shell and the row they are on is how many shells there are.
- In an atom the protons and neutrons are in the nucleus and electrons are on the outside.
Rocks & Building materials
- Thermal decomposition is when calcium carbonate in limestone breaks down when heated to make calcium oxide and carbon dioxide.
- Equation for thermal decomposition:
Calcium carbonate(CaCO2) > Calcium oxide(CaO) + Carbon dioxide(CO2)
- Limestone reaction cycle:
Calcium carbonate > heat and carbon dioxide > Calcium oxide > add water > calcium hydroxide > add more water and filter > calcium hydroxide solution > add carbon dioxide > Calcium carbonate.
- Cement is made by heating limestone with clay in a kiln.
- Concrete is made by mixing aggregate with cement, sand and water.
- Advantages of limestone quarrying: jobs, useful products, limestone has many uses like making buildings and statues.
- Disadvantages of limestone quarrying: large area of land used up, machine used releases carbon dioxide into atmosphere, noise and site pollution, habitats destroyed.
Metals and their uses
- An ore is a rock which contains enough metal to make it economically worth while to extract.
- Iron is extracted by extracting iron from iron ore by reducing it using carbon in a blast furnace.
- An alloy is a metal that is mixed with other elements e.g. steel is an alloy of iron.
- Aluminium - Uses: drinking cans, cooking foil, saucepans, high-voltage electricity cables, areoplanes, space vehicles and bicycles. ~ Properties: silvery, shiny metal
- Titanium - Uses: aircraft bodies, racing bikes, set engines, nuclear reactors, hip joints. ~ Properties: silvery-white metal.
4 ways of extracting copper
- Smelting ~ heat copper ore very strongly in a furnace with air to produce crude copper.
- Displacement ~ iron is more reactive that copper so it can displace copper from its solutions. Iron + copper sulfate > iron sulfate + copper
- Bioleaching ~ bacteria feed on low-grade metal.
- Phytomining ~ Plants can absorb copper ions from low-grade copper ore as they grow.
Crude oils & fuels
- Fractional distillation is the process in which we seperate crude oil into useful components, according to their boiling points. The properties of each fraction depends on the size of the hydrocarbon molecules.
- Carbon dioxide causes greenhouse gases - sulphar dioxide causes acid rain - nitrogen oxide causes acid rain - particulates are toxic.
- Alkanes ~ saturated hydrocarbon ~ CnH2n+2 ~ e.g. methane
- Alkenes ~ unsaturated hydrocarbon ~ CnH2n ~ e.g. ethane
- Biodiesel: Good - less harmful to habitats, burns cleanly ~ Bad - large area of land used.
- Ethanol: Good - made from sugar ~ Bad - requires alot of land to grow plants.
- Hydrogen: Good - potential future fuel, better for the environment ~ Bad - burnt to produce pure hydrogen and releases CO2.
Products from oil
- Cracking is producing saturated hydrocarbons which are used as fuels and unsaturated hydrocarbon called alkenes.
- Alkanes + Bromine water > stays orange
- Alkenes + Bromine water > clear colourless
- Polymerisation is making plastics.
- Light-sensitive polymers is an example of new polymers as when they are in light then are less sticky and peels off.
- Hydrogels is another example of new polymers, they are wound dressings and let the body heal in moist, sterile conditions this is good for treating burns.
- Ethanol can be produced into 2 ways,
- by the hydration of ethene: C2H4(g) + H2O(g) > C2H5OH - ethene + water = ethanol
- and fermentation: C6H12O6 > 2C2H3OH + CO2 - glucose = ethanol + carbon dioxide
- Problems with plastic are that the are biodigradable, when some are burnt they release carbon monoxide, and some are made from ethanol and crude oil which is running out.
- Biodigradable plastics are made from plant products and cornstarch, they harm wildlife and take up space in landfil sites.
- Vegetable oil can be extracted from seeds, nuts and fruits by pressing or by distillation.
- They provide nutrients and lots of energy, they are important foods and can be used to make biofuels.
- The molecules in vegetable oils have hydrocarbon chains, they have carbon-carbon double bonds (C=C) which are unsaturated. And so when they are in bromine water they decolourise.
- Vegetable oil is very useful in cooking as it has high boiling points, they become solids at room temperature that are suitable for spreading.
- The hydrogenated oils have higher melting points because they are more saturated, the reaction is also called hardening where increasing the temperature makes the chemical reactions go faster, so food cooks faster in oil than water.
- Oils do not dissolve in water but oils and water can be used to produce emulsions, these have special properties. Emulsions are made from vegetable oils which are used in many foods, e.g. ice creams is a frozen emulsion. Emulsifiers stop oil and water from seperating into layers.
- Emulsifiers have molecules in which one part is hydrophobic(tail end) and the other hydrophillic(blob). The tail end is attracted to oil and blob end is attracted to water.
- Emulsifiers improve the texture of foods enabling water and oil to mix, this makes fatty food more palatable and tempting to eat like a cake.
Chemistry Unit 1 - Revision