On a rain-soaked canoe trip in Algonquin Park with my adult sons a few years back, I was pleased to note the excellent performance of a kerosene-fuelled camp stove.1
Figure 1: WhisperliteTM International kerosene-fuelled camp stove (MSR online store)
This prompted me to investigate the specs of the stove. I was intrigued by the manufacturer’s claim that one ounce (30 mL) of kerosene could boil 1.6-L of water. The Sceptical Chymist2 in me needed to verify this claim—and to have my students do the same.
This activity is an excellent application of Thermochemistry, in particular Hess’s Law of Heat Summation using average bond energy values. Further, the activity asks students to do some good ol’ problem solving.
Students are provided with the Tech Specs (see table 1) of the WhisperliteTM International camp stove. They are directed to look at the claim regarding the stove's fuel requirements for boiling water, using kerosene fuel.
Table 1: Manufacturer’s claims regarding the camp stove
Students are then asked to validate the manufacturer’s claim that 1 ounce of kerosene will boil 1.6 L of water.
This question is more complicated than meets the eye. You are strongly advised to consult the supplementary handout, available in the Supporting Information, in the form of a student worksheet, with full solutions. It contains questions to guide the teacher (and student), and lists the assumptions necessary to solve this problem. (Log into your ChemEd X account to access. Don't have an account? Register here for free!)
When students have completed the assignment, consider posing the following, perhaps as a test question:
1. a) Use the manufacturer’s claim of 600 mL of kerosene burning for 155 minutes to calculate the effective power (W) of the stove.
b) How does this value compare with the effective (actual)—power of the stove determined in the assignment?
2. If circumstances permit, have your students carry out this determination. Be sure to try it yourself first. Design an experiment to determine the effective power of a camp stove. Consider the fuel for the stove to be
b) propane, delivered by a pressurized cylinder, as shown.3
For both fuels, assume that you have your school’s Chemistry lab at your disposal. Answer in point form; including calculations as required.
- WhisperliteTM International, MSR WhisperLite International V2 Stove System - PRFO Sports
- Apologies to Robert Boyle cf. Robert Boyle – The Sceptical Chemist | SciHi Blog
- Coleman Propane Gas Cylinder/Canister, Fuel For Camping Stoves, Lanterns & Heaters, 16-oz | Canadian Tire