[cliverlong]

Hi,

   Is my argument correct below?

  the reaction being considered is dissolving solid calcium carbonate in hydochloric acid to produce aqueous Calcium Chloride, carbon dioxide gas and more water.

   Now if we take 0.1 moles of CaCo₃ (RMM = 100). This is 10 grams

  0.1 moles CaCo₃ creates 0.1 mole CO₂

Since for an ideal gas  V = nRT / P

using SI units
if we do the experiment at 20C (293K)
R = 8.3 J · K^-1 · mol^-1
n = 0.1 mol
P = 10⁵ Pascals

So V (CO₂ generated)  = 0.0025 m³

and since 10⁶ cm³ = 1m³

V (CO₂ generated) = 2,500 cm³

Now if the balance can weigh to an accuracy of + / - 0.01g, if we take 10g CaCo₃ then the accuracy of the readings from the balance is 0.01 / 10 = 0.001 = + / - 0.1%

However, if my gas syringe can contain around 200 cm³ and my reading error is + / - 2 cm³, that will be around + / - 25 cm³ in the 2,500 cm³ of CO² created by the reaction - by accumulating the errors from reading the syringe about 12 times.

So the error in reading the gas syringe will be (+ / - 25) / 2,500 = + / - 0.01 = + / - 1%

Therefore for this experiment, the readings from the gas syringe are the major source of error.


Thanks

Clive

[Borek]

In general seems OK.