[MS_SUMTER2010]

Help determine whether a reaction would occur. If a reaction occurs, write the balanced equation. If no reaction occurs, write no reaction.

a) calcium and water
b) magnesium and water
c) rubidium and lithium chloride
d) potassium and aluminum oxide
e) silver and calcium nitrate
f) fluorine and potassium iodide
g) magnesium bromide and chlorine
h) copper ad iron (III) sulfate

[Unknown008]

Remember those:

1. Metal + Water --> Metal Hydroxide + Hydrogen gas

(Note, the reaction which occurs depends on the reactivity of the metal and the state of water)

2. A more reactive metal will displace a less reactive one from it's salt/oxide.

3. A more reactive halogen (Group VII) will displace a less reactive halogen from a halogen salt.

Now, give it a try, we'll check the answers afterwards. :)

[MS_SUMTER2010]

I don't understand but this is what I have so far.

a) Ca + 2h20 yeilds Ca(OH2) +h2
b) Mg +2H20 yeilds Mg(OH2) + H2
C) NO REACTION
D) K + AL YEILDS
E) NO REACTION

[Unknown008]

Could you please write your symbols well? Capital letters where necessary?

a. Yes, calcium reacts with cold water vigorously and can burn with a brick red flame.

b. Magnesium reacts slowly with cold water, but rapidly with steam. But the latter then often results in magnesium oxide.

Mg + H2O --> MgO + H2

c. Rubidium is further down Group I of the periodic table. You'll notice that the lower you go, the more reactive the metal is, in that group.

Eg.
Sodium reacts vigously with cold water, and sometimes catches fire (flame is yellow).
Potassium reacts explosively with cold water and burns with a lilac flame.

So, rubidium will react with lithium chloride, forming rubidium chloride.

Rb + LiCl --> RbCl + Li

But in practice, the rubidium will either first react with the oxygen in the air to form rubidium oxide, or with water (more vigorous than potassium, remember?) first, forming RbOH. You can say that reactions releasing the most heat usually occur first.

d. Same as above. Potassium is a reactive metal, more reactive than aluminium. So, you get potassium oxide and aluminium metal.

3K + Al2O3 --> 3K2O + 2Al

It's as if the more reactive metal is stronger, and snatches the oxygen, chloride, nitrate, or whatever from the weaker metal.

e. Right! Calcium is more reactive that silver! Since silver is 'weaker' it cannot take the nitrate from the 'mighty' calcium!

f. Here, you get to know another property in a group, the halogen group, which is Group VII of the periodic table. Instead of going more reactive down the group like in the Group I, the reactivity increases up the group. Hence, the order of more reactive elements are, from strongest to weakest: fluorine, chlorine, bromine, iodine, astatine.

Fluorine is stronger than iodine, right? So, it'll take potassium from iodide.

F2 + 2KI --> 2KF + I2

g. Same as above, the chlorine is 'stronger' so will take the magnesium from bromide.

MgBr2 + Cl2 --> MgCl2 + Br2

h. That is the same as in c. d. e. Iron is the stronger metal, hence, copper cannot take the sulfate from the iron. So, no reaction.

[MS_SUMTER2010]

So the answer or potassium and aluminium oxide is

3K 0 + 2Al
2

[Unknown008]

It's



I made a mistake in balancing earlier. Sorry.

[MS_SUMTER2010]

What about the magnesium bromide and chlorine reaction

[Unknown008]

I gave it to you too... see the last reaction in my post...

...
g. Same as above, the chlorine is 'stronger' so will take the magnesium from bromide.

MgBr2 + Cl2 --> MgCl2 + Br2
...