# Chemical Formula Equations

1. Feb 2, 2012

1. The problem statement, all variables and given/known data

I have a couple of problems here that are all part of one homework problem. A,B,C, and D. I have completed what I believe are the correct answers, but I really don't know for sure. This is an online chemistry class, and it really is not very good. I've watched about 3 hours of Khan Academy videos, and 1+ hours of Brightstorm, plus all my required reading- and I just seem to be missing something.

Anyway, if someone could just look these over I would appreciate it.

Give the chemical formula equation for the following reactions.

(A.) Potassium metal reacting with water to produce potassium hydroxide and hydrogen gas.

(B.) The bicarbonate, $HCO_3$ ion reacting with the $H^+$ ion to produce water and carbon dioxide.

(C.) Copper metal reacting with silver nitrate solution to make silver metal and copper(II) nitrate.

(D.) Iron metal reacting with oxygen gas to make iron(III) oxide.

2. Relevant equations
3. The attempt at a solution

(A.)
$K + H_2O \rightarrow KOH + H^2$

=$2K + 2H_2O \rightarrow 2KOH + H_2$

(B.)
=$HCO_3^- + H^+ \rightarrow H_2O + CO_2$

(C.)
$Cu + AgNO_3 \rightarrow Ag + Cu(NO_3)_2$ Substitute $X=NO_3$
$Cu + AgX \rightarrow Ag + CuX_2$
$Cu + 2AgX \rightarrow 2Ag + CuX_2$

=$Cu + 2AgNO_3 \rightarrow 2Ag + Cu(NO_3)_2$

(D.)
$Fe + O_2 \rightarrow Fe_2O_3$
$2Fe + 1.5O_2 \rightarrow Fe_2O_3$
$2(2Fe + 1.5O_2 \rightarrow Fe_2O_3$

=$4Fe + 3O_2 \rightarrow 2Fe_2O_3$

Any advice, or even a swift boot in the right direction, would be greatly appreciated.

Thanks,
Mac

2. Feb 3, 2012

### Staff: Mentor

In general you got it right. The only thing I would modify would be to add (s), (aq) and (g) to reagents to show their state, so for example your second reaction would look like

Cu(s) + 2AgNO3(aq) -> 2Ag(s) + Cu(NO3)2(aq)

3. Feb 3, 2012

Ah, thanks Borek. I forgot about adding the physical state symbols. My teacher does require that.

Just curious, looking at these after a nights sleep, does the second equation $HCO_3^- + H^+ \rightarrow H_2O + CO_2,$ need to instead be this $HCO_3^- + H_2^+ \rightarrow H_2O + CO_2$?

It seems to me that Hydrogen can not stand alone. (even though that's how it's worded in the book)

Thanks again.

4. Feb 3, 2012