Gas Stoichiometry

Question

A 0.650 g sample of SrCO3 reacts with HCl as described above, using the same apparatus we used in our experiment, at a temperature of 29 oC and an atmospheric pressure of 750 mm Hg. What is the pressure of CO2 that is produced in this reaction?

a. 750 mm Hg

b. 720 mm Hg

c. 780 mm Hg

d. none of these

Answer 1

We don't know what was described "above" nor do we know what the "same" apparatus is, but I'll guess.

Here is the reaction:

SrCO₃(s) + 2HCl(aq) ==> SrCl₂(aq) + CO₂(g) + H₂O(l)

moles SrCO₃ = 0.650 g x 1 mol/147.6 g = 0.004404 moles

moles CO₂ produced = 0.004404 moles SrCO₃ x 1 mole CO₂/mole SrCO₃ = 0.004404 moles CO₂

I'm guessing the volume remains constant, i.e. you didn't collect the CO2 into a balloon for example...

So, use the ideal gas law PV = nRT and substitute the following values and solve for P

P = nRT/V

P = ?

n = 0.004404 moles

R = 62.36 mm Hg*L/K*mol

T = 29 + 273 = 302K

V = the volume, in liters, of the apparatus you used in your experiment

The answer will come out in mm Hg for pressure