Lab Report for Gay Lussac's Law: Gas Volumes Used (Lab Report Sample)

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Lab Report for Gay Lussac's Law
INTRODUCTION
The law of combining volumes is concentrated on the properties of gases. According to this law, gases react in a simple whole number ratio provided they reacting gases are at the same pressure and temperature. The Gay-Lussac’s law is also sometimes known as Avogadro’s Law. The ratio obtained when gases react is used to balance chemical equations of gases because the ratio represent stoichiometric coefficients of the gases. The aims of the experimentation is to calculate the ratio of reaction between unknown gas A and oxygen and use that ratio in determining the percentage of oxygen gas in a given sample of air by titrating gas A into air.
PROCEDURE
In the first part of the experiment which involves determination of the ratio between gas A and oxygen, the following method was followed. Water was filled to the mark of 2/3 of a plastic basin. A tightly stopped flask containing gas A was then allowed to float in inverted position on the basin. A 100mL of graduated cylinder was then inverted and filled with water completely. 40mL of gas A was drawn from the flask containing it using an empty syringe. A known volume of 10mL of Gas A was then filled into the graduated cylinder that was inverted. Using a different syringe 10mL of oxygen gas was added into the graduated cylinder containing gas A. The two volumes of the gases were recorded. Gas A and oxygen were allowed to react and mix for around 2 minutes. The volume of any residual gas was detailed and then disposed into a large basin. The above procedure was repeated for other three test involving 10mL of gas A and 20mL of oxygen, 10mL of oxygen and 20mL of gas A, and finally 30mL of Gas A and 10mL of oxygen. The residual volumes of gases were recorded separately.
In the second part of the experiment to determine oxygen percentage in air, the following steps were followed. An inverted graduated cylinder of 100mL was first filled with 50mL of air sample. The volume of air obtained was recorded to ±1mL. Gas A 5mL portions of were titrated into the graduated cylinder containing air sample. The two gases were slightly agitated by vibration the cylinder. The mixture was then allowed to react to completion for one minute. Residual volume of gas from the experiment was recorded. Gas A was constantly added in increases of 5mL at a time until 40mL of gas A was used. The equivalents residual volumes of gases were recorded after every test.
DATA : Table 1: Results from part one
Gas volumes used (mL)

Residual volume (mL)

Gas A

Oxygen

Observed

Predicted

10

10

12

5

10

20

15

15

20

10

2

0

30

10

6

10

Table 2: Result for part two

Residual gas in cylinder(mL)

Total A added (mL)

Decreasing Residual

50

0


47

5


44

10


42

15

Increasing Residual

43

20


46

25


51

30


55

35


60

40

CALCULATIONS
From the volumes, the best ratio of the reacting volume of the two gases is 20:10. This ratio can be simplified to 20/10 = 2. To calculate the excess gases in trial 1, 2, and 4 the following expression was used;
mL A used/mL O2 used < oxygen is in excess and mL A used/ mL O2 used > A is excess
For trial 1, 10 mL A10 mL O2 = 1 mL A1 mL O2 < 2 A1 O2 = oxygen is in excess
10 mL O2 - (10 mL Ax1 A2 O2) =5mL, oxygen was in excess
For trial 2, 10 ...