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Chemical Formula. D. Crowley, 2007. Chemical Formula. To understand chemical formula. Definitions. Define an element, compound and mixture An element is made up of just one type of atom A compound is two or more elements, chemically bound
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Chemical Formula D. Crowley, 2007
Chemical Formula • To understand chemical formula
Definitions • Define an element, compound and mixture An element is made up of just one type of atom A compound is two or more elements, chemically bound A mixture is made of different substances, not chemically bound
Elements & Compounds • Look at the rocket - it uses liquid hydrogen as a fuel • The engine mixes this hydrogen with oxygen, adds a spark and the reaction takes place • The elements are • They react together, forming a compound called
Elements & Compounds • Look at the rocket - it uses liquid hydrogen as a fuel • The engine mixes this hydrogen with oxygen, adds a spark and the reaction takes place • The elements are hydrogen and oxygen • They react together, forming a compound called hydrogen oxide (water)!
Chemical Equations • Chemical equations show us our reactants and products reactants products • They can be word or symbol equations, e.g. Carbon + oxygen carbon monoxide C + O CO
Formula • Elements and compounds can be represented using chemical formula • We use numbers in the formula, which represents the number of atoms present (as a ratio) C = 1 atom of carbon (C) O2 = 2 atoms of oxygen (O) CO2 = 1 atom of carbon (C); 2 atoms of oxygen (O) NaCl = 1 atom of sodium (Na); 1 atom of chlorine (Cl) H2SO4 = 2 atoms of hydrogen (H); 1 atom of sulphur (S); 4 atoms of oxygen (O)
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Graphical • Can you draw the following substances • The formula should help you graphically represent them… Oxygen O2 Carbon dioxide CO2 Sodium chloride NaCl Sulphuric acid H2SO4 Carbon C Nitric acid HNO3
Questions • Write down how many atoms there are (and of what element) for the following: - • C - e.g. 1 x carbon (C) • CO2 • H2O • CaCO3 • H2SO4 • NaCl • HNO3 • CuCO3 • MgCl2 • Carbon monoxide • Hydrogen oxide
Presentation • If there is time left, produce a poster in your book which explains formula (as a revision guide) • You may wish to add examples, and ways to work out the ratio of atoms…