Chemistry Unit 1

The fundamental ideas in chemistry

The three subatomic particles are protons, electrons and neutrons.
2 electrons fill the inner shell, 8 fill the rest of the shells.
Elements in the same group of the periodic table all have the same number of electrons in their outer orbitals.
To calculate the number of neurtons in an atom you should take the number of protons form the mass number (mass no. - protons).
When atoms bond, they gain/lose/share electrons so that they end up with a full outer shell.
Covalent bonding involves the sharing of electrons. It happends between non-metals (of the same atom-element, 2 different atoms, or a compound), in order for the atom to have a full outer shell.
Ionic bonding involves electrons been given from one atom to another. It happens between non-metals and metals, in order for the atom to have a full outer shell.

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The formula of limestone is CaCO3.
The limestone cycle: 1.Limestone/Calcium Carbonate (CaCO3) [heated strongly] 2.Quicklime/Calcium Oxide (CaO) [2-3 drops of water] 3.Slaked Lime/Calcium Hydroxide (Ca(OH)2) [dissolve it in water] 4. Lime Water/Calcium Hydroxide Solution (Ca(OH)2) [carbon dioxide bubbles]
Advantages of limestone quarrying in a National Park is that it creates many jobs for unemployed, there is huge demand for the materials quarried, therefore if we quarry there will be more material to supply/sell.

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An ore is a material that conatins metals in such quantities that makes it worth mining for.
Metals above carbon in the reactivity series are extracted from their ores by the method of electrolysis (the breaking down of a compound uisng electricity).
Electrolysis is expensive because it is needed for the breaking down of the compound.
An alloy is a metal made from two combined metallic elements.
Titanium is a useful metal because it resists corrosion (lasts a very long time) , it has a very high melting point, it is light and also strong- this makes it very useful as an a airplane engine or an artificial joint. However, electrolysis must be used to extract it.

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A hydrocarbon is a compound made from hydrogen and carbon.
Crude oil is separated by a process called fractional distillation.
In hydrocarbons, all the carbon atoms have 4 chemical bonds.
The gas that causes acid rain is sulphur dioxide.
When a hydrocarbon burns, the products are always water and carbon dioxide.

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Long hydrocarbons are cracked because the products (shorter hydrocarbons) are more useful, e.g aviation fuel.
Cracking method: 1.Place wool soaked in hyrdocarbon in the end of a boiling tube, alongside broken pot. 2.Put a delivery tube in the end of the boiling tube. 3.Put the end of the boiling tube into a beaker full of water. 4.Begin to heat the end od teh boiling tube with a bunsen burner. 5.Collect the gas bubbles with a testube- place it upside down, just above the end of the delivery tube in the water. 6.Place a bung in the end of the testube collecting the gas once satisfied with the amount collected.
Alkenes are unsaturated, therefoer they conatine a double bond to the carbon (betwenn hyrdogen and carbon)
Polymerisation is a chemical process that combines several monomers to form a polymer(ic)compound.
Ethene is turned into ethanol by fermentaion.

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Methods of extractig oils from plants are crushing and pressing the plant, or by dissolving in a solvent- once the oil is dissolved, the solvent is removed by distillation, and impurities such as water are also removed, to leave pure oil.
Oils are hardened using hydrogenation- adding hydrogen to the solition at about 60 degrees centigrade
To test for unsaturation in an oil you can see if it is liquid at room temperature, as most are.
The most common use of plant oils is in food. You can also use bromine water- it becomes colourless when in an unsaturated solution and if it stays the same colour then it is saturated.
An emulsifier is a substance that stops the oil and water from separating into layers.

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The layers of the earth are: the crust, the mantle, the outer core and the inner core.
Rock formations and volcanoes occur when tectonic plates meet.
Before Alfred Wegener, scientists thought that continents were formed as the Earth cooled.
The main gases in the atmosphere are Nitrogen, Carbon dioxide, Argon and Oxygen.
Carbon dioxide in the atmosphere has decreased over the past four billion years, because plants use it in photosynthesis and it is/was absorbed into the oceans.

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