molarity and dilution

dilute與無dilute個 solution當然有好大影響啦 咁唔係dilute黎做咩呢
dilute左solution會影響其density, concentration, rate of reaction, etc

至於你第二條q 就有少少問題
因為dilute個 solution 係想 save chemicals
當你dilute個 solution 之後係絕對唔會again 用哂所有chemicals去做experiment
你只會用一部份去做 咁咪做到一樽chemical可以做多次experiments
所以係唔會同樣用咁多mole數同個reactant reacts

concentration其實concentration of solutuion 係會affect rate of reaction , 解釋就同上面嗰位一樣
concentration also 會affect the type of product produced.
你會喺oxidation and reduction 嗰課學到(你想知就read it by yourself)
我講個example
dilute sulphuric acid H2SO4 (aq) 同 Copper Cu 係冇reaction
但係concentrated sulphuric acid H2SO4 (aq) 同 copper 係有reaction
2 H2SO4 + Cu --------- CuSO4 + SO2 + 2 H2O

如果有ａｎｙ　ｏｔｈｅｒ　ｑｕｅｓｔｉｏｎｓ　，　ｅ－ｍａｉｌ　ｍｅ　
我會幫你　因為我係今屆ｃｅ　ｓｔｕｄｅｎｔ

2007-05-26 17:38:24 補充：
Ｐ．Ｓ．　　ｄｉｌｕｔｅ前後隻ｓｏｌｕｔｉｏｎ都是咁多ｍｏｌｅ 數，（Mole = Molarity of solution * Volume of solution)　但係你唔係用唒所有ｄｉｌｕｔｅｄ　ｓｏｌｕｔｉｏｎ去做ｅｘｐｅｒｉｍｅｎｔ，所以係唔會同樣用咁多mole數同個reactant reacts

2007-05-26 17:48:26 補充：
等我解釋下點解ｍｏｌｅ唔會變(Mole = Molarity of solution * Volume of solution)當你ｄｉｌｕｔｅ　隻ｓｏｌｕｔｉｏｎ　時，ｍｏｌａｒｉｔｙ　下跌，　而因為你係加緊水，ｖｏｌｕｍｅ　上升，最後下跌同上升互相抵消ｒｅｓｕｌｔｉｎｇ　ｉｎ　ｎｏ　ｃｈａｎｇｅ　ｉｎ　ｍｏｌｅ．

First, you should know that dilute solution means the volume of solute(always is water) is larger than the volume of solvent, so the main reactant(always is the solvent) in the solution will be less than original solution(equal volume of solute and solvent).
Second, no. of mole is calculated by mass over molar mass.
Mass and molar mass are not changed, so no. of mole will not change.
Third, the dillute solution always use water to dilute, so the total mass of solvent will not change, so the reactant will not change.
Finally, the number of collision of the both reactants will be decreased than original solution, so the rate of reaction will be lower than the original solution.

No. of mole o係 dilute 左同冇 dilute 都會係一樣....
因為 no. of mole = mass/ molar mass.
所以你就算dilute 左 (e.g. 加多左水...都係會一樣)
不過 個molarity 就會變啦...
molarity = no. of mole / volume....
但係dilute 左ge solute 就會影響個rate of reaction
因為你d 野dilute 左...咁個frequency of collision between reactants 就會少左..
所以會decrease the rate of reaction