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Unformatted text preview: Pure
water consists of 89 percent oxygen and 11 percent hydrogen by mass. Pure salt contains 39 percent sodium and
61 percent chlorine. Mixtures. Pure substances can be brought together to form mixtures. Mixtures are combinations of two
or more substances. They can be homogeneous or heterogeneous depending on the state of subdivision of the
components. Salt water is a uniform mixture of table salt (NaCl) and water. The original crystals of salt have
dissolved and are dispersed evenly. On the ordinary scale of observation we cannot detect any chemical or
physical differences between adjacent regions of the mixture. The particles of salt are too small to observe. A
mixture that has the same composition throughout is said to be a homogeneous mixture. The properties of a
homogeneous mixture vary since they depend on the percent composition. For example, the hardness of steel, a
solid mixture of iron and carbon, depends on the percentage of carbon that is added to iron. Homogeneous
mixtures are also called solutions .
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This note was uploaded on 09/15/2009 for the course CHEM 102 taught by Professor Bastos during the Spring '08 term at Adelphi.
- Spring '08