How Do You Determine Reactivity in Double Displacement Reactions?

[extraordinarygirl]

I am having trouble with double displacement reactions. I know for some of them, no reactions will occur because the metal isn't strong enough to displace the other metal . I was wondering if any of you could clear this up.
Do I see if the first metal can displace the second metal, or do i see if teh second metal can displace the first?

--If you could answer me quickly, that would be awesome.

 

[extraordinarygirl]

Can someone please help me I have a test on this tomorrow!

 

[Cesium]

I am guessing what you are talking about is actually a single replacement reaction where one more reactivite metal displaces another metal in solution.

The activity series is as follows:
Lithium
Potassium
Barium
Calcium
Sodium
Magnesium
Aluminum
Manganese
Zinc
Chromium
Iron
Cobalt
Nickel
Tin
Lead
Hydrogen (acids)
Copper
Silver
Mercury
Platinum
Gold

For example consider the reaction between copper and silver nitrate.
Cu + 2AgNO3 --> Cu(NO3)2 + 2Ag

This reaction occurs because copper is more reactive than the silver which is in solution as silver nitrate. The converse of that equation would not occur:

Ag + Cu(NO3)2

because silver is less reactive than copper.

Anything above hydrogen on the reactivity scale will react with an acid. For example: zinc and hydrochloric acid

Zn + 2HCl --> ZnCl2 + H2

So basically look at the bare metal and see if it is higher up on the chart than the metal in the compound. If it is, then the reaciton will occur.

A double displacement reaction deals with two ionic substances in solution and will occur with the formation of a precipitate or a gas.

For example:
Na2CO3 + CaCl2 --> 2NaCl + CaCO3(s)

This reaction occurs because CaCO3 (calcium carbonate) is insoluble.

Na2CO3 + 2HCl --> 2NaCl + H2CO3

Carbonic acid is unstable: H2CO3 --> H2O + CO2(g)

This reaction occurs because CO2 gas is formed.

 

[extraordinarygirl]

Thank you so much