我連是不是我打都不太記得!!
那是我今年的班主任當年懷著小企鵝教我們的。
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8-3 Aqueous Solutions
Aqueous Solution: Water samples containing dissolved substances are aqueous Solutions.
solution: dissolving medium
solate: dissolved particles example:tape water, sodium chloride solution (NaCl)
Solution:
_homogeneous and stable.
_solute particles can be either ionic or molecular with their ave. Diameters are less than 1nanometer (10 m ),the filter unimpeded.
_solution and solate may be gases, liquids or solids.
_substances dissolve in water because they are polar or ionic.
8-7 Units of Concentration
Precent ( volume/ volume):percent means ”parts per hundred”
Precent ( weight/ volume): the number of grams of solute per 100 ml of solution.
Parts per million(ppm),parts per billion(ppb): for expressing concern, of extremely dilute solutions.
One ppm means 1 mg of solute per kilogram of solution, or a pebble with a volume of 1 cm in a cube of concrete measuring 1 m along each edge.( 1m=1 million cubic centimetres)
One ppb means 1 g of solute per kilograme of solution, or a pebble with a volume of 1 cm in a cube of concrete measuring 10m along each edge (1000 m = 1 billion cm )
8-8 Molarity (M):
Molarity (M): the number of moles of a solute dissolved in 1 L of solution.
Diluting solution of known molarity: The number of moles of solute does not change when a solution is diluted.
MV=mv ( L or ml)
Ex: How to prepare 100 ml of 0.4m MgSO from a stock solution of 2M MgSO ?
20 ml of 2M MgSO into 100 ml volumetic flask.
8-9 Colloids & Suspensions
Suspensions : A piece of clay shaken with water froms a muddy mixture. The particles in a typical suspensions have an adverage diameter greater than 100 nanometres (nm).
Suspensions are heterogneous, clay and water (by filtration or centriguge)
Colloids: The particles of a size between 1 and 100 nm are colloids.
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