1
$\begingroup$

I conducted a lab in which different concentrations of $\ce{HCl}$ were used and $\ce{Na2CO3}$ was added. The pressure change was measured for a reaction with the different concentrations.

Now I am going to find the reaction rate for the reactions. I am thinking that using the pressure data, I can find the reaction rate by doing the following.

Consider:


${PV = nRT}$ ($R$ and $T$ are constant so they can be taken out of the equation)

${PV = n}$

$P = {\frac nV}$ (Knowing that $\text{c}={\frac nV}$)

${P} = \text{c}$


Seeing as pressure is directly related to concentration, then couldn't I just use the pressure data to find the rate and then relate that to the concentration change over time?

The alternative would be to use ${PV=nRT}$ for each second of the reaction and find the concentration change that way. However, I want to consider the possibility of doing it this way.

One problem I forecast would be the units: kPa/s vs. mols/L

$\endgroup$

closed as unclear what you're asking by Tyberius, Mithoron, ron, M.A.R., Jon Custer Sep 4 '17 at 19:21

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ You can't "take out" $R$ and $T$ from the ideal gas equation. If you do not know the value for a variable, then the most you can do is try to cancel it out in a ratio: $\frac{P_1V_1}{P_2V_2}=\frac{n_1RT}{n_2RT}=\frac{n_1}{n_2}$ $\endgroup$ – Nicolau Saker Neto Nov 24 '13 at 19:10
  • $\begingroup$ What I'm trying to say is that during the experiment Temperature was constant .. I based my information on this chemguide.co.uk/physical/basicrates/pressure.html $\endgroup$ – Ds.109 Nov 25 '13 at 1:56