http://web.umr.edu/~gbert/Gas/AIGases.htmlName _____________________________________ Hour ____
Weighing Gases
Preliminary Questions
1. If the "empty" container is weighed with the cap on (W1), then
filled with helium and again weighed with the cap on (W2), will the weight
increase, decrease, or stay the same?
______W2 is greater than W1 _______ W2 is less than W1
_____ W2 is the same as W1
2. If the cap is removed from the container filled with helium, the weight will immediately decrease by the weight of the cap. Will the weight then increase, decrease, or stay the same?
___ increase ______ decrease _____ stay the same
3. If the "empty" container is weighed with the cap on (W1), then filled with air and weighed with the cap on (W2), will the weight increase, decrease, or stay the same?
______W2 is greater than W1 _______ W2 is less than W1
_____ W2 is the same as W1
Procedure
Avogadro's Hypothesis (Amadeo Avogadro, 1811) states that
"Equal volumes of different gases (at the same temperature and pressure)
contain the same number of molecules."
This program allows you to weigh a container (of fixed volume) filled with
different gases at a fixed temperature and pressure. The number of moles of
gas should be the same in each case.
Operation of the Simulation
|
GASES button: |
allows selection of eight known gases, an unknown gas, and air. |
|
TARE button: |
(on balance) zeroes the balance. |
|
FILL button: |
(on gas cylinder) fills the container with the designated gas (cap of the container must be removed for operation). |
|
Data Sheet: |
provides a data sheet for recording observations. |
|
cap on/off : |
puts cap on or off container. |
|
on/off balance : |
puts container on or off the balance. |
|
flip : |
changes container position upright/inverted for filling with gases that are heavier or lighter than air. |
Notes:
1. A gas which is lighter than air will escape more quickly when the container if upright than when it is inverted. The opposite effect is observed for a gas which is heavier than air.
2. Any movement of the open container accelerates the escape of gas.
3. The FILL process completely replaces any previous gas. However, the new gas begins to escape as soon as the hose is removed.
4. Re-sizing the Window under Netscape re-loads new values for temperature,
pressure, and volume. Reload/Refresh does this in any browser.
Experiment
Fill the container with each of the known gases and the unknown gas, taring
the balance between readings. Weights may be recorded on the Data Sheet.
Weighing Gases: Data Sheet (round gas mass to the hundredth (0.01g) of a
gram.
|
Observed Mass(g) |
Observed Mass(g) |
|
|
Hydrogen |
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
|
|
g |
g |
Which gas had the greatest mass?
Which gas had the least mass?
Which gases have a density less than air?
Which gases are lighter than air?
Which gases are heavier than air?
Which gases should be filled with the bottle upside down?
Which gases should be filled with the bottle upright?
Why is the bottle heavier for some gases and lighter for others?