You are provided with a syringe, a petri-dish firmly attached to the base of the movable piston (plunger) of the syringe, a Set of weights, and other necess...
Question 1 Report
You are provided with a syringe, a petri-dish firmly attached to the base of the movable piston (plunger) of the syringe, a Set of weights, and other necessary apparatus.
- Pull the piston of the syringe upward until it can no longer move. Read and record this position of the piston on the graduated mark on the syringe as V\(_{o}\).
- Clamp the syringe and ensure that it is vertical.
- Place a mass M= 500g gently at the center of the petri-dish.
- Read and record the new position of the piston as V.
- Evaluate V\(^{1}\).
- Repeat the procedure for four other values of M= 1000g, 1500g, 2000g, and 2500g.
- Tabulate your readings.
- Plot a graph with V\(^{-1}\) on the vertical axis and M on the horizontal axis, starting both axes from the origin (0,0).
- Determine the slope, s, of the graph.
- Evaluate k = s\(^{-1}\).
- State two precautions taken to ensure accurate results.
(b)i. When a weight is placed on the petri-dish, which quantities of the gas in the syringe (\(\Omega\)) increases; (\(\beta\)) decrease?
ii. What is responsible for the pressure exerted by a gas in a closed vessel?
Answer Details
(a) Table of readings
| S/N | Mass, \(M\) (g) | Volume, \(V\) (cm3) | \(V^{-1}\) (cm−3) |
|---|---|---|---|
| 1 | 500 | 9.30 | 0.108 |
| 2 | 1000 | 7.40 | 0.135 |
| 3 | 1500 | 6.40 | 0.156 |
| 4 | 2000 | 5.40 | 0.185 |
| 5 | 2500 | 4.60 | 0.217 |
For example, when \(M=500\text{ g}\),
\[V^{-1}=\frac{1}{9.30}=0.108\text{ cm}^{-3}.\]
Graph of \(V^{-1}\) against \(M\)
Using two widely separated points on the line of best fit, approximately \((500,0.107)\) and \((2500,0.214)\):
\[s=\frac{0.214-0.107}{2500-500}=\frac{0.107}{2000}=5.35\times10^{-5}\text{ cm}^{-3}\text{g}^{-1}.\]
\[k=s^{-1}=\frac{1}{5.35\times10^{-5}}=1.87\times10^{4}\text{ g cm}^{3}.\]
Precautions
- The syringe was clamped firmly in a vertical position.
- Each mass was placed gently at the centre of the Petri dish, and the piston reading was taken at eye level to avoid parallax error.
(b)
(i) On placing a weight on the Petri dish, the pressure of the trapped gas increases, while its volume decreases.
(ii) Gas pressure in a closed vessel is caused by the continuous random collisions of gas molecules with the walls of the vessel.
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