Chemistry research design
CaCO3+2HCl=CaCl2+H2O+CO2
Procedure:
Materials:
- CaCO3 and HCl
- Measuring cylinder
- Gas syringe
- Beaker
- Thermometer
Procedure:
- Put 5g CaCO3 (0.05 mol) powder in the conical flask. Prepare 200mL 0.5M HCl= 0.1 mol in
another beaker. Try to disperse the CaCO3 powder evenly along the bottom of the flask
- Use gas syringe + airtight stopper. First make sure gas syringe is pumped fully (piston at the
front), and make sure there are no liquids inside. If possible oil/lubricate the piston? Then
just put the syringe inside the stopper and prepare to cap it on the beaker immediately
- Hold the stopper + gas syringe near the neck of the conical flask. Quickly pour the HCl
solution into the conical flask, immediately cap the stopper and gas syringe, and start timer
- Gently swirl to make sure all the CaCO3 powder is exposed to HCl and not just stacked in
an island over the HCl
- I should probably put cotton somewhere, but I don’t know where I can put it. Maybe I can
like tie some cotton or thin cloth over the mouth of the gas syringe and secure it with tape
or rubber band maybe
Data collection:
- Record the measure of the gas syringe every 2 seconds for the first 10 seconds, then on
intervals of 5 seconds. If possible, record with a video so I can track the measuring with
much finer detail like every second
- The displacement of the gas syringe= volume of CO2 produced.
- Theoretical displacement of gas syringe should be about 56 mL, but I would expect gas
leakages so maybe I’m expecting 45 to 50?
- When plotting the volume data on a graph, when the volume stops increasing I would count
that as the time when reaction finished.
- Use equation r = kA^nB^m, using different time:volume points along the graph to compute
k
Repeat the experiment with different concentrations of HCl (like 0.05, 0.1, 0.2, 0.5M)
Rough/general error sources (not detailed)
- HCl splash on walls of conical flask
- CaCO3 too rough or didn’t contact with HCl all at once (clumped)
- H2O vapor got into the gas syringe
- Gas leakage from capping, or escape through holes in the stopper
- Leakage inside the gas syringe: gaps between piston and syringe wall, may escape into the
back cavity of the gas syringe