The discussion centers on the classification of salt and sand as heterogeneous or homogeneous mixtures. Participants clarify that salt, being a pure compound (sodium chloride), is homogeneous at the molecular level, while sand is heterogeneous due to its mixture of different particles. The conversation emphasizes the distinction between mixtures and pure substances, with specific references to the properties of compounds and phases in mixtures. Ultimately, the consensus is that pure salt is homogeneous, whereas mixtures like sand are heterogeneous.
PREREQUISITESChemistry students, educators, and anyone interested in understanding the distinctions between homogeneous and heterogeneous mixtures, particularly in the context of everyday substances like salt and sand.
kenvin100 said:i normally think of heterogeneous and homogeneous this way
homogenous: think of it as 2 boys (same gender)
heterogeneous: boy and girl (different genders)
please don't laugh lol
so salt is heterogeneous cause u see different particles (color wise w.e.)
but salt, its all the same white crystals or w.e. so thay makes it heterogeneous
ya this isn't the greatest explanation chemistry wise but it helps me remember!
hope it helped bud :-)
Mitchtwitchita said:Salt isn't a mixture, it's a compound.
The question is if sand, or salt is a homogeneous/heterogeneous mixture? About salt, If he intended "grains of salt mixed with air", then it's a heterogeneous mix, but if you consider a single grain it's not a mix at all since it's a pure compound. In general, when you have 2 or more different compounds (and so a mix), the mix is homogeneous if it's formed by a single phase and so is a solution, heterogeneous if two or more phases. Ex: water and oil forms two separate phases (even when one of them is finely emulsionated into the other); water and alcohol instead forms an only phase (homogeneous mix) because they forms a solution.Saladsamurai said:I was just asked "Are salt and sand heterogeneous or homogenous mixtures?" I can see that sand is heterogeneous, but why is salt heterogeous?
Casey
Saladsamurai said:I was just asked "Are salt and sand heterogeneous or homogenous mixtures?" I can see that sand is heterogeneous, but why is salt heterogeous?
Casey
It doesn't matter if you have equal amounts of Na and Cl; in other compounds (e.g. water) you don't have but they are still homogeneous (NON mixtures); every pure compound in one only phase is homogeneous.Andy Resnick said:I would say pure salt is a homogeneous substance. No matter how much of it you have, you have equal amounts of Na and Cl. There are well-defined intensive quantities (density and specific heat, for example) that do not vary depending on where you took a small sample of salt.
lightarrow said:It doesn't matter if you have equal amounts of Na and Cl; in other compounds (e.g. water) you don't have but they are still homogeneous (NON mixtures); every pure compound in one only phase is homogeneous.
A piece of solid brass is homogeneous or not, for you?Andy Resnick said:Well, yes.. but that's not what I meant. In any homogeneous compound, regardless of how much you have, you retain the stoichiometric ratio of the components. This is not true for things like sand or concrete.
Brass is an example of alloy which is a solid solution (with one phase only if Zn concentration is less than 37%) so it's homogeneous, but it doesn't have a specific composition.Andy Resnick said:That's an interesting question. I would say macroscopically it is homogeneous. I don't know enough about the microscopic structure to say anything else. Steel compounds (cementite, austentite, etc) are heterogeneous on a microscopic scale.