IB Math Exploration

Determining the Enthalpy of Combustion of a Wood Chip
IB Chemistry 12
September 18, 2014
Ryan Ingham

Table 1: Raw data collected from the temperature probe and scale for the water, the aluminum can and the wood chip. (Quantitative)

Quantity
Initial Temperature (±0.1K)
Final Temperature (±0.1K)
Aluminum Can
46.29g (±0.01g)
296.5
314.7
Water
250g (±0.1g)
296.5
314.7
Wood Chip
Before: 4.64g(±0.01g)
After: 3.29g (±0.01g)
NA
NA

Table 2: Qualitative observations made during the process of the combustion of the wood chip.

Before
During
After
Qualitative Observations
The water had tiny air bubbles along the surface. The wood chip was completely dried out. The aluminum can had been cleaned of any residue from previous labs. The wood chip was positioned on a pin underneath the aluminum can.
While the wood chip burned it had an orange flame. The thermometer was touching the bottom of the aluminum can while measuring the temperature change of the water. The bottom of the can was black from previous use.
The flame eventually burnt out and a dark grey smoke arose from the wood chip. The chip had shrunken in size compared compare to before the procedure. There were little bits of black soot coating the underneath of the aluminum can.

Graph: Temperature vs Time for Combusted Wood Chip
Sample Calculations:

Final Temperature of Water – Initial Temperature of Water = Change in Temperature of Water

314.7K (±0.1) – 296.5K (± 0.1) = 18.2K (±0.2)

Mass of Wood chip before combustion – Mass of wood chip after combustion = Mass of combusted wood chip

4.64g (±0.01) – 3.29g (±0.01) = 1.35g (±0.02)

mcΔTwater + mcΔTcan = mH°comb (wood chip)

(250g ±0.1) (18.2K ±0.2) + (46.29g ±0.01) (0.902J) (18.2K ±0.2) = (1.35g ±0.02) H°comb (wood chip)

(250.0g ±0.04%) (4.18KJ)(18.2K ± 1.1%) + (46.29g ± 0.02%) (0.902J) (18.2K ±1.1%) = (1.35±1.5%)