# IB Chemistry - Boyle's Law Lab Report

Boyle’s law

The relationship between pressure and volume

Raw data

1. Average book weight = (1441 + 1439)/2 = 1440 ±0.5g
2. The total pressure on the piston equals the pressure from the books plus the atmospheric pressure = 1034g/cm² (it does not have uncertainty because it was given)

Data processing

1. Radius= diameter/2 = 2.7/2 = 1.35 ±0.05cm
2. Area of the contact = πr² = π*(1. 35 ±0.05)² = 5.73 cm²
3. % of uncertainty on Area → r = 0.05/1.35*100 = 3.7% → π doesn’t have uncertainty but r² has 2 r so I need to add uncertainty of 2 r. → 3.7 + 3.7 = ±7.4% so the absolute uncertainty is 5.73*7.4% = ±0.42 cm²
4. % of uncertainty on Mass of book = 0.5/1440*100 = 0.04% = ±0%
5. Pressure = mass(of book)/area = 1440/5.73 = 251g/cm²
6. % of uncertainty on pressure = % of uncertainty on Mass + % of uncertainty on Area + % of uncertainty on the total pressure on the piston equals the pressure from the books plus the atmospheric pressure = 0 + 7 + 0 = ±7%
7. Pressure with 7% of uncertainty = The total pressure on the piston equals the pressure from the books plus the atmospheric pressure + Pressure(mass of book/area)

= 1034 + 251*№ of book ±(1034+251*№ of book)*0.07 = 1034 + 251*1±(1034+251*1)

*0.07 = 1285 ±90.0g/cm²

1. % of uncertainty on Volume = 0.5/measured volume*100 = 0.5/36*100 = ±1.39% (each volume has their own % of uncertainty)
2. Absolute uncertainty = 36*1.39/100 = ± 0.500
3. Pressure*Volume = k(constant) = (1034 + 251*№ of books)*36 = (1034 + 251*1)*36 = 46260
4. % of uncertainty on Constant = % of uncertainty on Mass + % of uncertainty on Area + % of uncertainty on the total pressure on the piston equals the pressure from the books plus the atmospheric pressure + % of uncertainty on Volume = 0+ 7 + 0 + 1 = ±8%

Questions

• According to the result of the experiment, the relationship between variables such as volume and pressure was inversely related. However, the graph that showed the relationship between 1/volume and the pressure was directly related.
• Gas law was defined by many scientists. However, the relationship between volume and pressure was proved by Boyle who made Boyle’s laws which defined pressure and volume are inversely proportional. If the pressure goes up, the volume will go down and vice versa. However, if we put the volume inversely, then the relationship between pressure and the inversed volume will be changed into ...