Chemistry C1

Chemistry C1

1. Fundamental Ideas

   • Atoms Elements and Compounds
     • All substances are made from atoms
     • Element- Made from one type on atom
     • Chemical symbols represent atoms
     • Compound- Made from more than one element
   • Atomic Structure
     • Nucleus made up of protons and neutrons
     • Charge
       • Protons- Positive Neutrons- Neutral Electrons- Negative
       • Atoms have overall chrrge of 0
     • Atomic number is equal to the number of protons
       • Elements arranged on periodic table in order of proton number
     • Mass number is sum of protons and neutrons
       • So, Mass Number - Atomic Number = Number of Neutrons
   • Arrangement of Electrons in Atoms
     • Noble gases (Group 0) are very stable so are unreactive
     • Electrons are arragned in shells around the nucleus
       • Shell one holds 2 electrons, after that they hold 8
       • Shell one is closest to the nucleus
       • Electrons fill from shell one first
     • Elements in the same group have same number of electrons in their outer shell
   • Forming Bonds
     • Metals bond with non metals ionically
       • Ion- Charged particle
     • Formula of ionic compouds shows the ratio of ions
     • Non metals bond covalently to form molecules
     • Formula of a molecule shows that atoms in the molecule
   • Chemical Equations
     • During reactions, atoms get rearraged, but never created distroyed or changed
     • Mass of Reactants = Mass of Products
     • Word equations state the name of reactants and proucts, where as symbol equations give formulas
       • Symbol equations should always be balanced

2. Rocks and Building Materials

   • Limestone and its Uses
     • Limestone is Calcium Carbonate (CaCO₃)
     • Uses
       • Building material
       • To make calcium oxide
       • Cement
       • Concrete
         • Cement, aggregate, sand and water
     • Limestone decomposes when heated
       • Thermal Decomposition
   • Reactions of Carbonates
     • Metal carbonates decompose when heated to produce the metals oxide and carbon dioxide
     • Carbonate + Acid = Salt + Water + Carbon Dioxide
     • Carbon Dioxide turns Calcium Hydroxide (Lime Water) cloudy, by forming insoluble calcium carbonate
   • Limestone Reaction Cycle
     • 1. Thermal decomposition of calcium carbonate to form calcium oxide and carbon dioxide
       • CaCO₃ -> CaO + CO₂
     • 2. Hydration of calcium oxide to form calcium hydroxide
       • CaO + H₂O -> Ca(OH)₂
       • Calcium hydroxide is an alkali used to neutralise acids such as acidic soil
     • 3. Dissolving of calcium hydroxide to form calcium hydroxide solution
       • Ca(OH)₂ + H₂O -> Ca(OH)₂ (aq)
     • 4. Carbon dioxide added to form calcium carbonate precipitate
       • Ca(OH)₂ + CO₂ -> CaCO₃ + H₂O
   • Cement and Concrete
     • Cement is made by heating clay and limestone in a kiln
       • Product is then ground to a powder
     • Mortar is made by mixing cement sand and water
     • Concrete is made by mixing aggregate (small stones) into mortar
   • Limestone Issues
     • Quarrying and processing Limestone
       • Advantages
         • More employment and local job oppurtunities
         • Improved roads
         • Increased trade
       • Disadvantages
         • Dust and noise
         • More traffic
         • Loss of habitat

3. Metals and their Uses

   • Extracting Metals
     • Metals are usually found in the Earth's crust, often as compounds with other elements such as oxygen
     • Ore- Metal compound containing enough metal to make extracting it worth while
     • Unreactive metals are found in the Earth as the metal
     • Metal oxides, where the metal is less reactive than carbon, can be reduced using carbon
   • Irons and Steels
     • Iron oxides can be reduced in a blast furnace to produce iron
     • Blast furnace iron is too brittle to use
     • Most iron is converted into an alloy, steel
     • Steel contains calculated quantities of carbon and other elements
   • Aluminium and Titanium
     • Resist corrosion
     • Lower densities than other strong metals
     • Have to be extracted by electrolysis
     • Extraction is expensive due to the large amounts of energy needed
   • Extracting Copper
     • Most copper is extracted from ores by smelting
     • Copper is then purified by electrolysis
     • Copper rich ores are a limited resource so scientists are find new ways of sourcing copper
     • Phytomining- Using plants to absorb copper compounds, which are collected from the plant's ashes
     • Bioleaching- Uses bacteria to produce copper compound solutions
     • Copper can be extracted from solutions by displacement or electrolysis
   • Useful Metals
     • Central block of periodic table are the transition metals
     • Transition metals have useful properties such as being strong yet malleable
     • Most metals we use are alloys
   • Metallic Issues
     • Recycling saves energy and limited resources
     • Using metals in construction
       • Disadvantages
         • Uses limited resources
         • Can rust
         • More expensive than other materials
       • Advantages
         • Strong
         • Malleable
         • Ductile
         • Good conductors of heat and electricity

4. Crude Oils and Fuels

   • Fuels from Crude Oil
     • Crude oil is a mixture of many compounds
     • Distillation separates a mixture of liquids
     • Most of the compounds in crude oil are hydrocarbons- only contain hydrogen and carbon
     • Alkanes are saturated hydrocarbons, meaning there are as many hydrogen atoms as possible in the molecule
   • Fractional Distillation
     • Crude oil can be separated into fractions by fractional distillation
     • Properties of these fractions depend on molecule size
     • Fractions with lower boiling points are less viscous and more flammable
   • Burning Fuels
     • Burning hydrocarbons produces carbon dioxide and water
     • Burning hydrocarbons in a limited air supply causes incomplete combustion and may produce carbon monoxide and soot
     • When burnt sulphur compounds produce sulphur dioxide and nitrogen compounds form nitrogen oxides
       • Both can cause acid rain
   • Cleaner Fuels
   • Alternative Fuels

5. Products from Oil

   • Cracking Hydrocarbons
   • Making Polymers from Alkenes
   • New and Useful Polymers
   • Plastic Waste
   • Ethanol

6. Plant Oils

   • Extracting Vegetable Oil
   • Cooking with Vegetable Oil
   • Everyday Emulsions
   • Food Issues

7. Our Changing Planet

   • Structure of the Earth
   • Restless Earth
   • Earth's Atmosphere in the Past
   • Life on Earth
   • Gases in the Atmosphere
   • Carbon Dioxide in the Atmosphere