<p>I am awful at these! It would be great if someone could provide an answer, and then explain:</p>
<p>Magnesium turnings are added to a solution of iron(III) chloride.</p>
<p>Small chunks of solid sodium are added to water.</p>
<p>Hydrogen chloride gas is bubbled through a solution of potassium cyanide.</p>
<p>Sulfur trioxide gas is bubbled into a solution of sodium hydroxide.</p>
<p>2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g) (i think. im going off memory here)</p>
<p>3Mg + 2Fe(+3) yields 3Mg(+2) + 2Fe - single replacement, then cancel out the spectator Cl</p>
<p>Na + 2(H2O) yields 2Na(+) + 2OH(-) + H2 (I'm not too sure about this one)
NaOH is a strong base, and disassociates completely in water. </p>
<p>H(+) + CN(-) yields HCN - hydrocyanic acid is a strong acid, and does not disassociate in water. The potassium is a spectator ion.</p>
<p>SO3 + 2NaOH yields Na2SO4 + H2O
When you see sulfur trioxide, you should think of a sulfate ion. Sulfate has a -2 charge, so you need 2 Na+ to balance it. H2O is the other product.</p>
<p>yeah.. i forgot you have to show the dissociation of NaOH</p>
<p>Dragonscale333's reactions are basically correct with a few minor errors.
1) In reaction 3, HCl is written undissociated because it's a gaseous reactant, not a solution. Cl- then needs to be included as a product. Also - HCN is a weak acid, not a strong acid. (But like draongscale says, it does not dissociate.)
2) In reaction 4, NaOH and Na2SO4 would both dissociate in solution, so the Na+ cancels as a spectator ion.</p>
<p>i don't understand how you get NaOH... someone want to explain?</p>
<p>That's just how all period I metals (Na, K, Sr, etc.) react with water. It's really single replacement if you think of water as a hydrogen ion plus a hydroxide ion (HOH). The sodium replaces the hydrogen, which becomes (quite explosively, which is fun for demonstration) a gas, bonding with the hydroxide.</p>
<p>HCN is not a strong acid, I think you mean weak.</p>
<p>ahh....
gfaith, you're right. Thanks for noticing my mistakes.
Does anyone know whether we need to put the states of matter?</p>
<p>No, you don't need to. Sometimes they will ask about the states of matter in the part B question for each net ionic equation problem.</p>
<p>"i don't understand how you get NaOH... someone want to explain?"</p>
<p>Reactions with water: (not in net ionic form, not balanced)</p>
<p>Active metals plus water --> metal hydroxide plus H2
Li + H2O --> LiOH + H2 (Single Replacement like machinegungeek said)
Active metal oxides plus water --> metal hydroxide (no H2)
CaO + H2O --> Ca(OH)2
Nonmetal oxides plus water --> acid
SO2 + H2O --> H2SO3</p>