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CHEM AND BIO HELP AND TIPS HERE

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Dana:
oh and another qs, once i was solving past papers and they asked what the product would be when a metal (forgot which one) reacted with water. i thought it would give the hydroxide and hydrogen but instead it actually gave the oxide :S then with another metal, it gave the hydroxide. how can we tell which one forms with each metal?

Raywin:
Guys, this has been bugging me. In some papers, the mole concept Q, sometimes the easy way to solve the problems is to use something like the volume ratio is same as the mole ratio or something. Umm, what is this and when can we use this? Thanks a lot in advance. :)

MasterMath:

--- Quote from: Dana on June 06, 2010, 04:51:12 pm ---oh and another qs, once i was solving past papers and they asked what the product would be when a metal (forgot which one) reacted with water. i thought it would give the hydroxide and hydrogen but instead it actually gave the oxide :S then with another metal, it gave the hydroxide. how can we tell which one forms with each metal?

--- End quote ---
Hmm .. look at this
                 K
                 Na
                 Li
                 Ca
                 Mg
                 Al
                 C
                 Zn
                 Fe
                 Pb
                 H
                 Cu
                 Ag
Okay thats the reactivity series .. as you go down reactivity decreases .. ANY METAL ABOVE Ca .. reacts with COLD water to form hydroxide and H2
Anything under it forms oxide and H2 :D
Hope i helped

Dana:

--- Quote from: Raywin on June 06, 2010, 04:52:42 pm ---Guys, this has been bugging me. In some papers, the mole concept Q, sometimes the easy way to solve the problems is to use something like the volume ratio is same as the mole ratio or something. Umm, what is this and when can we use this? Thanks a lot in advance. :)

--- End quote ---
thats when the equation involves only gases. then you can use mole volume ratio or whatever is called :P

Dana:

--- Quote from: MasterMath on June 06, 2010, 04:53:30 pm ---Hmm .. look at this
                 K
                 Na
                 Li
                 Ca
                 Mg
                 Al
                 C
                 Zn
                 Fe
                 Pb
                 H
                 Cu
                 Ag
Okay thats the reactivity series .. as you go down reactivity decreases .. ANY METAL ABOVE Ca .. reacts with COLD water to form hydroxide and H2
Anything under it forms oxide and H2 :D
Hope i helped

--- End quote ---
you did thanks loads :D what abt calcium does it form a hydroxide or oxide?

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