Purpose
To determine the efficiency of our lab Bunsen burners.

Procedure Hints

• The amount of heat actually absorbed by the beaker of water can be determined by the formula q = mDTCp
• The amount of heat actually produced can be predicted by meauring the gas flow rate, and applying Hess's Law for the possibilities.  Consider the gas to be either methane (CH4), ethane (C2H6), or propane (C3H8).  There is another lab you may have already performed in which you calculate the molecular weight of the burner gas and identify it.

• Determine flow rate of gas (in units of volume/time).
• Use hose clamps to control gas flow (on/off).
• Use q = mDTCp to determine the heat absorbed by the water.
• It’s easier to determine DT for a set time.
• Use the following (unbalanced) reaction to get the theoretical q:
[burner gas]_(g) + O_2(g) ® CO_2(g) + H₂O_(g) + q
• Use the appendix to calculate q
• Efficiency can be calculated by
 

eff =	actual q	x 100
	predicted q

How would the efficiency change if we assume the water in the products is a liquid?

• Title stuff:  Name(s), date, class, title
• Purpose
• q for each gas possibility, in units of J/mol
• A complete data table.  Each number should be decribed, shown, and labeled.  Line up the decimal places!
• A sample calculation of efficiency, assuming the gas is methane (CH4).
• The efficiency assuming each of the other two gases.
• A choice for which gas you think most likely, inculding explanation.