front 1 Mole equation.... | back 1 Mass / mr |
front 2 Mass (interm of moles) equation... | back 2 Moles x mr |
front 3 Concentration equation... | back 3 Mass / volume |
front 4 Mass (interm of concentration) equation... | back 4 Concentration x volume |
front 5 Oxygen gas test result | back 5 Glowing splint relights |
front 6 Hydrogen gas test result | back 6 Lit splint makes a squeaky pop |
front 7 Carbon dioxide gas test result | back 7 Limewater turns cloudy |
front 8 Chlorine test result | back 8 Damp litmus paper turns white |
front 9 Example of an exothermic number | back 9 Any negative number |
front 10 Example of an endothermic number | back 10 Any positive number |
front 11 In an endothermic reaction is the energy released when bonds are formed more or less than the energy needed to break the bonds? | back 11 Less |
front 12 In an exothermic reaction is the energy released when bonds are formed more or less than the energy needed to break the bonds? | back 12 More |
front 13 Bond energy calculation unit of final answer... | back 13 KJ/mol |
front 14 Enthalpy (energy) change calculation... | back 14 Bonds broken - bonds made |
front 15 Calculate the enthalpy change when water is formed from H² and O² | back 15 . Add the bond enthalpy of all the bonds broken Eg. H-H ×2 = 2×436 = 872 O=O ×1 = 1×498 = 498 872 + 498 = 1370 . Add the bond enthalpy of all the bonds made Eg. O-H ×4 = 4×464 = 1856 . Calculate enthalpy change Eg. 1370 - 1856 = -486 . Explain why a reaction is exothermic or endothermic Eg. This is a negative sign meaning it's exothermic |
front 16 Why is a reaction exothermic? | back 16 A reaction is exothemic because the energy released when bonds are formed is more than the energy needed to break the bonds |
front 17 . Why is a reaction endothermic? | back 17 A reaction is endothermic because the energy released when the bond are formed is less than the energy needed to break the bonds |