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leehuan

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We have 2 oxygen atoms in the O2 molecule?

They each gain 2.

[This is NOT what happens: O + 4electrons -> O(4-)]
 

drsabz101

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In the reaction why does the oxygen gas go from a gaseous state to a solid ?
 

leehuan

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CaO is a compound. There is no more "oxygen" molecule there's only calcium oxide.

(atom means nothing, atoms build up elements and compounds and the elements/compounds are the species)
 

Shuuya

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Is it true tin and water cannot react? Why though
Tin reacts with steam (gaseous water)

Sn(s) + 2 H2O(g) -> SnO2(s) + 2 H2(g)

In metal + steam reactions, metal oxide + hydrogen gas is formed rather than metal hydroxide + hydrogen gas

This is because Tin is a relatively unreactive metal at room temperature (so does not readily react with water/oxygen) , and higher temperatures are required for a reaction to occur, where water becomes steam.
 
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leehuan

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Tin reacts with steam (gaseous water)

Sn(s) + 2 H2O(g) -> SnO2(s) + 2 H2(g)

In metal + steam reactions, metal oxide + hydrogen gas is formed rather than metal hydroxide + hydrogen gas

This is because Tin is a relatively unreactive metal at room temperature (so does not readily react with water/oxygen) , and higher temperatures are required for a reaction to occur, where water becomes steam.
True also for aluminium

Reactions with water are useful as they can be used to determine the reactivity series of metals.
 

drsabz101

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Okay so I am going to post up my answer for the reaction of potassium and hcl acid let me know r/w
 

drsabz101

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Okay ! Another q. Sorry this is like a chem marathon for me ^^

How do I balance

Ni(g) + H20(l) -> Ni(OH)2 + H2 (g)
 

drsabz101

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Thnx . Just wanted to know how to tell which elements DON'T react with oxygen by looking at the periodic table
 

leehuan

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A lot of elements react with oxygen actually. That one's ambiguous.
 

drsabz101

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Like for example lead and water have no reaction, but how can u tell from looking straight from the table
 

drsabz101

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And what does it mean if a certain metal never 'displaces' itself
 

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