Using the Ideal Gas Law to find R!
Statement of problem:
Background info (write in notebook):
What is the ideal gas law? What do the variables represent?
What is R (value and meaning)?
The chemical reaction you will use is a reaction of calcium metal and water.
What is the balanced chemical equation for the formation of calcium hydroxide and hydrogen gas from
calcium metal and water?
This is an experiment where you will be collecting a gas over water (just like we learned in class). What
do you need to consider when collecting gases over water? What are the relevant equations? What
other information is required to calculate Pgas?
Procedure:
Fill the collection vessel ¾ of the way full of water.
Measure the temperature of the water.
Place the syringe upside down into the collection vessel uncapped. Immerse the syringe in the water so
that all the air is removed and cap the syringe.
Fill the reaction tube a little more than ½ of the way full of water.
Weigh out the calculated amount of Ca (_______g)
Add the calcium to the reaction tube and IMMEDIATELY cap it. The reaction happens quickly so delay
will result in error.
Collect gas in the syringe. When reaction is complete, raise the syringe so that the water level matches
the water level in the collection vessel.
Record the volume.
Find Pgas, and use the actual mass of Ca to find the moles of H2.
Use the ideal gas law to find R.
Repeat once and add your R values to another group to get a final average value for R. Calculate error.
Data:
Ideally you want to collect approximately 0.045L of gas. Find the initial mass of Ca to be used ______
Equation to find Pgas:
Temperature of water:
Atmospheric pressure today: