The flow dirrection of electricity

Author Message   991085 Username: 991085 Registered: 04-2003 Posted on Saturday, June 21, 2003 - 04:26 pm:    我想問如果考考內試我唔寫個d (aq),(s),(l)symbol會唔會扣分.. 同埋我想知佢問"the flow dirrection of electron" 我係咪唔可以答"clock-wise"或者"Antie-clock wise"? 'acid' 同 "base" 有咩分別???? 佢話有個實驗dilute"HNO3"add "Mg" 見到有氣體 given out 佢問係咩Gas 咁我應該答 我應該答NO定係NO2   Chio U Kim Username: cuk Registered: 04-2003 Posted on Saturday, June 21, 2003 - 06:09 pm:    Whether the state symbols are required depends on how the questions are asked. To play safe, you should be able to give correct state symbols I do not recommend this kind of answers for the direction of electron flow. I prefer the following ones : The electrons flow from left to right or from right to left; The electrons flow from electrode A to electrode B. Acids and bases are chemical opposites. When mixed, they cancel each other's properties. Examples of bases iinclude : metal oxides and metal hydroxides. Bases that are soluble in water are called alkalis. See Excercise 6 Question 1(d).   991085 Username: 991085 Registered: 04-2003 Posted on Monday, June 23, 2003 - 04:30 pm:    alkalis 係咪insoluble in water??? bases 就係soluble in water?   Chio U Kim Username: cuk Registered: 04-2003 Posted on Monday, June 23, 2003 - 11:42 pm:    All alkalis are soluble in water. All alkalis are bases but not all bases are alkalis. Only the bases that are soluble in water are called alkalis.   991147 Username: 991147 Registered: 04-2003 Posted on Tuesday, June 24, 2003 - 04:03 pm:    do we need to memorize all the alloy and their uses and also do we need to memorize the use of metals?   Chio U Kim Username: cuk Registered: 04-2003 Posted on Tuesday, June 24, 2003 - 09:18 pm:    Yes. But no need to remember the % by mass of constituents (E.g. Brass contains 70% of Cu and 30% of Zn)   991035 Username: 991035 Registered: 04-2003 Posted on Tuesday, June 24, 2003 - 10:38 pm:    wanna ask a silly question even though I don't know..... HOw many moles of carbon atoms contain the same number of atoms as 0.13 moles of N ?   Chio U Kim Username: cuk Registered: 04-2003 Posted on Tuesday, June 24, 2003 - 11:15 pm:    0.13 moles of C atoms contains the same number of atoms as 0.13 moles of Nitrogen atoms (N) 0.13 x 2 moles of C atoms contains the same number of atoms as 0.13 moles of nitrogen molecules (N2) It is because one molecule of N2 contains two atoms of nitrogen