stoichiometric coefficient in HCl titration

[Top_gun]

Hihi,

My goal is to titrate a water sample (100ml) with 0.1M HCl and plot it.
But I don't understand the meaning of the stoichiometric coefficient in REACTION.

I found this code in an example, but I don't know how to interpret it?
How do I change it for the use 0.1M HCl?

REACTION 1
    H2O        0.0555   
    HCl        0.00016      
    5 moles in 10 steps

Thanks for your help.


whole code:

Code: [Select]

SOLUTION 1
    temp      11.88
    pH        7.23
    pe        4
    redox     pe
    units     mg/l
    density   1
    Alkalinity 322 as HCO3
    Ca        112
    Cl        22.6
    F         0.06
    K         1.7
    Mg        9.7
    N(5)      3.3 #NO3-
    Na        11
    O(0)      8
    S(6)      49.5 as SO4
    Si        5.4
    -water    0.1 #100 ml #kg water, default = 1 kg


#### Titration a solution with 0.1M HCl

REACTION 1
    H2O        0.0555
    HCl        0.00016
    5 moles in 10 steps

USER_PRINT
10 PRINT SOLN_VOL * 1000 #Volume of the solution, in milli liters

USER_GRAPH 5
 -chart_title  "Titration Curve"
 -axis_titles "Acid Added (mL)", "pH"
 -axis_scale x_axis  0 16 1
 -axis_scale y_axis 0 14 0.5
 -start
10 VT=SOLN_VOL*1000
20 V = VT-100 #Gesamtvolumen minus Ausgangslösung (100ml) = Zugabevolumen
30 pH = -LA("H+")
110 GRAPH_X V
120 GRAPH_Y pH

END

[dlparkhurst]

There are approximately 55.5 moles of H2O per kilogram of water (~1 kilogram divided by 18, where 18 represents the gram formula weight of H2O). If you have a 0.16 m HCl solution, then (assuming the  solution density is 1 kg/L) you have 0.16 mol/L of HCl. 1 mL of the solution contains 0.0555 mol of water and 0.00016 mol of HCl. 1 mol of the reaction is equal to 1 mL of 0.16 N HCl.

If it helps, you could do it as

REACTION
H2O 55.5
HCl  0.1
0.001 mol
END

Here the 55.5 and 0.1 would be the moles in 1 L of 0.1 N HCl (approximately) and the amount of reaction, 0.001 produces the number of moles in 1 mL of solution.
 

[Top_gun]

Great.
Thank you very much for your explanation :-)