f4 chem (mole)

又唔可以話廢既,
好多野現實生活都用唔著嫁la，maths differentiation, econ demand-supply, bio inheritance, physics universal gravitation, history Cold War, 中史 隋唐五代, geog magma convection, 中文 修辭手法, art shading, 文學 文言文........


另外，mole 好似唔係用黎計重量嫁wor......

2012-02-24 00:07:11 補充：
formula mass = sum of relative atomic masses of all atoms in the formula of the compound

molar mass = mass of 1 mole of that substance

the most obvious difference between two of them is that formula mass(or atomic mass or molecular mass) carries no units; while molar mass carries a unit : g/mol (or g mol^-1)

If you really want a equation, you may use
molar mass = sum of relative atomic masses of all constituent atoms g/mol

But when answering questions, they are usually regarded the same.


To study the "mole" chapter,
exercise is the most important
Practice makes perfect

the questions about mole concept is usually related to different experiments(neutralization, redox etc. , I guess you haven't learnt them yet, but "mole" is the fudamental for such topics)

they usually require you to find mass, limiting agents, percentage yield, teorectical values or anything similar

So, once you have learnt the "key", the only way to be faster is to do more.
I remember when I was studying the mole chapter, I do about 20 questions a day.

One tip : type in a programme in your calculator, it may probably help you get faster, a bit.

Hope this helps!

relative atomic mass其實係永=廢既,現實生活根本用唔著
不過某一日有個科學家無聊得濟搵左12g既carbon有幾多粒atoms
就計到6.02x10^23呢個數
佢就定義1mole做6.02x10^23粒atoms既重量啦!!!
formula mass 同molar mass都係用carbon-12既scale黎計,當然個數字都一樣啦!!!
molar mass點搵?用formula mass囉!
點解?因為呢個係mole既定義(用6.02x10^23呢個騎呢數將抽象既formula mass同現實世界連接上!!!)

2012-02-20 18:51:17 補充：
永字打多左TT

2012-02-26 21:03:04 補充：
計得慢最重要當然係做多d練習啦,不過我個人會背一d元素既molar mass(如最常用既O=16 C=12 S=32.1 N=14 Na=23.0 同 Cl=35.5呢幾個),做果陣就唔洗成日(頡)黎(頡)去搵periodic table咁麻煩.

2012-02-26 21:04:31 補充：
賣個廣告先 強力推薦化學網站http://www.chemguide.co.uk/index.html#top