is water a pure substance or a mixture
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Answers:Food colouring - mixture (dyes dissolved in water or alcohol) Mouthwash - mixture (antiseptic dissolved in water and alcohol) Quartz - compound (silicon dioxide) Sulfur - element Cement - mixture (hydrated calcium alumio-silicates mixed with other materials) Ginger ale - mixture (carbon dioxide, sugar and flavoring dissolved in water) Sulfuric acid - compound (diHydrogen sulfate) Iron - element Liquid oxygen - element Carbon dioxide - compound Crude oil - mixture (various hydrocarbons) Glucose - compound (a carbohydrate)
Answers:Pure substance is a combination of two or more substances in which the constituents are present in a fixed proportion. These are formed by chemical reactions and release or absorb energy during this reaction. Theses can be separated by only chemical reactions. A mixture is a combination of two or more substances in which the constituents are present in any ratio. These are formed by physical methods and no energy is absorbed or released while mixing. These can be separated by physical methods. Potassium permanganate is a pure substance. copper chloride & sodium chloride, sodium chloride & water are mixtures. I'm very sorry that I don't know about phenolthaelin & sodium hydroxide.
Answers:Ignore Aurelius - he hasn't bothered to find out what a hydrate is! The water is not chemically bonded to the magnesium sulphate - no covalent or ionic bonds have to be broken to separate it, but the water is coordinated with the compound, so a hydrate is an example that is half way between a pure compound and a mixture - that's why there are differences in the websites you have searched. http://drtchemistry.wordpress.com/
Answers:1) It must NOT be a pure substance. Reasons? It has some smell, and it has color. The color is still left on whatever you marked when the smell is gone. Hence smell and color must be from two different substances. 2) a) Chocolate chip cookie - a heterogeneous mixture, since Chocolate chips are still visible b) Coffee with cream - a heterogeneous mixture, since cream itself is a heterogeneous mixture of butterfat and other components. Remember that butterfat does not dissolve in water. c) Aluminum foil - a pure substance d) Potting soil - a heterogeneous mixture e) Gold metal - a pure substance, or a homogeneous mixture, depends on the purity of gold.