Distillation makes use of differences in volatility, a measure of how easily a substance is converted to a gas at a given temperature. Two of these separation methods are distillation and crystallization. Homogeneous mixtures (solutions) can be separated into their component substances by physical processes that rely on differences in some physical property, such as differences in their boiling points. Separating Mixtures Through Physical Changes A solid forms if two clear liquids are mixed (look for floaties-technically called a precipitate). Different smell or taste (do not taste your chemistry experiments, though!).Bubbles are formed (but the substance is not boiling-you made a substance that is a gas at the temperature of the beginning materials, instead of a liquid).Unexpected color changes (a substance with a different color is made, rather than just mixing the original colors together).Temperature changes (either the temperature increases or decreases).Observations that help to indicate chemical change include: Some of the evidence for chemical change will involve the energy changes that occur in chemical changes, but some evidence involves the fact that new substances with different properties are formed in a chemical change. We have to make other observations to indicate that a chemical change has happened. We can't actually see molecules breaking and forming bonds, although that's what defines chemical changes. \): Burning of wax to generate water and carbon dioxide is a chemical reaction.
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