difference between mixtures and compounds

[skzoya]

i know in mixture two or more substance are not chemically bonded whereas in compounds substance are chemically bonded and also in mixtures substance can be separated by mechanical method but not compounds But i want to ask how can i identify whether substance is mixture or compound if it comes in theory exam there i cannot separate them ,nor can i predict whether substance are chemically bonded or not,how can i answer questions whether substance is mixture or compound in theory exams ? .

 

[Paperdoc]

Since you will not have the actual physical materials to examine, you must depend on the way the system is described in words. If the words are the name of a single chemical species, such as "Sodium Chloride" or "Sucrose" or "Iron", these are Compounds. (OK. "Iron" is a "compound" composed solely of one type of atom, rather than a product of a reaction between two elements.) But if the description says the system is composed of two different materials that have not reacted with each other chemically, like "Sand and Gravel", or "Sucrose and Salt", or even two things with chemical-sounding names like "Sodium Chloride and Potassium Chlorate", those are Mixtures. In fact, "Mixtures" can include both two (or more) physically separate things like those examples, and even uniform mixtures like true solutions, such as Sodium Chlolide dissolved in water. After all, those two components do not react chemically and they can be separated by purely physical means - for example, you can heat that solution to evaporate the water, leaving the Sodium Chloride as dried crystals.