2 Chemical reactions are occurring around us all the time Food cookingFuel being burned in a car’s engineOxygen being used in the human body
3 To describe the reaction that creates fire at the bunsen burner in lab: Methane gas reacts quickly with oxygen gas to produce fire, carbon dioxide, and water vaporThat’s a lot to write!
4 We can simplify the description of our reaction by using a word equation: Methane gas + oxygen gas →fire + carbon dioxide gas + water vaporStill a lot to write!
5 The simpler way to express a chemical reaction is to use formula equations: CH4 + O2 → CO2 + H2OHowever there is some information that is not shown in the formula equation:– State of matter– Fire/ Energy
6 We can show state of matter using the following symbols: (s) solid(l) liquid(g) gas(aq) aqueous solution(substance is dissolved in water)CH4 (g)+ O2 (g) → CO2 (g) + H2O (g) energy
7 Is the equation balanced? CH4 (g)+ O2 (g) → CO2 (g) + H2O (g) energyCH4 (g)+ 2O2 (g) → CO2 (g) +2H2O(g) + energy
8 Practice writing these equations: Hydrogen plus oxygen yields water H2 + O2 → H2 O Nitrogen plus hydrogen yields ammonia N2 + H2 → NH3 Aluminum bromide plus chlorine yields aluminum chloride and bromine AlBr3 + Cl2 → AlCl3 + Br2
9 Balance and include state of matter: 2H2 (g) + O2(g) → 2H2 O(l) N2 (g) + 3H2(g) → 2NH3(g) 2AlBr3(s) + 3Cl2(g) → 2AlCl3(s) + 3 Br2(l)
10 Nitrogen plus oxygen gas react and form dinitrogen pentoxide 2N2(g) + 5O2 (g) → 2N2 O5 (g)
18 Combustion Reaction CH4 + 2O2 → CO2 + 2H2O + energy A combustion reaction is a reaction in which an element or a compound reacts with oxygen, to form an oxide and heatHydrocarbons combust with oxygen to form carbon dioxide and water.