Mixtures 1. Elements or compounds not chemically bonded. a. Retain chemical identity b. Physical change may occur, or not c. Can be separated into components using physical properties i. filtering ii. Temperature of boiling or melting 2. classification a. pure—only single substance, to a specific level b. impure—a mixture i. heterogeneous—individual substances can be seen ii. homogeneous—same ratio in all parts 1. solution—all components same phase 2. suspension—different phases 3. solutions— a. can be solid, liquid or gaseous i. atmosphere ii. salt water iii. white gold b. definitions i. greater component is the solvent ii. lesser components are the solutes iii. concentration: solute amount/ solution amount (not solvent) 1. saturated: cannot dissolve any more 2. unsaturated: not at its capacity iv. mole: 6.02 x 1023 number of anything—molecules are small! 1. one formula mass (in grams) of a substance has one mole of molecules in it 2. molarity: moles of solute/liters of solution 4. solubility: a. ability to dissolve b. depends on attraction of molecules for one another i. similar between substances: infinitely soluble ii. greater to itself than solvent: weakly soluble c. temperature affects solubility i. commonly elevated with greater temperature ii. change of temperature can cause precipitation 5. soaps and detergents a. induced dipole—induced dipole attraction for grime b. ion—dipole attraction of water 6. softening hard water a. water contains Ca and Mg ions b. pass over Na ion saturated resins, displace Na ions7. water purification a. typical steps i. remove dirt by filtering, coagulation, and settling ii. aerate to improve taste iii. disinfect to neutralize cholera, typhoid fever, dysentery, hepatitis 1. ozone 2. chlorine 3. boiling 4. iodine tablets 5. ultraviolet treatment iv. remove toxic solutes 1. arsenic 2. nitrates 3. organic chemicals b. desalinization—make fresh water from salt water i. brackish groundwater or seawater ii. distillation 1. fuels 2. sunlight iii. reverse osmosis 8. wastewater treatment a. similar to purification of natural water sources i. screening, settling of solids ii. disinfect with ozone (preferred), chlorine or UV iii. secondary treatment involves aeration and additional settling iv. tertiary treatment includes
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