thorn_jac Posted September 1, 2008 Share Posted September 1, 2008 1. when placed in H2O, a sodium pellet catches on fire as hydrogen gas is liberated and sodium hydroxide forms. i put chemical change 2. evaporation i put physical change 3.pancakes cooking on a griddle i put physical change 4. A tire is inflated with air i put physical 5. luster i put chemical property 6. odor i put physical property please help Link to comment Share on other sites More sharing options...
insane_alien Posted September 1, 2008 Share Posted September 1, 2008 3 5 and 6 are wrong. the process of cooking anything causes a lot of complex chemical reactions to occur. most aren't noticable and merely result in a slight augmentation of the flavour, the most obvious reaction in pancakes is that they become solid. this is due to proteins breaking down and sticking to each other. luster is a physical property its to do with the physical characteristics of the electron shells in the atoms. odour is the detection of chemicals in the nose. this is achieved by a reaction and is hence a chemical property rather than a physical one. Link to comment Share on other sites More sharing options...
DrP Posted September 1, 2008 Share Posted September 1, 2008 Was about to say the same thing before IA beat me to it. Cooking causes a chemical change. Lustre is physical (how shiny). Smells are chemical - I was was going to give you this: http://www.scienceforums.net/forum/showthread.php?t=33167&highlight=smell - where we discussed smells before. Link to comment Share on other sites More sharing options...
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