<p>Lab:</p>
<p>we "made" fire on our hands using bubbles and are told to assume that we had 1L of CH4 per flame</p>
<p>we had water on our hands to prevent the burning</p>
<p>given:</p>
<p>water
m=2.18 g
C=4.184 J/g
Ti=30 C
q=</p>
<p>CH4
m=.72g
C=2.225 J/g</p>
<p>my answer (is this correct?)</p>
<p>-1.611411 J released by CH4 because .72*2.225=1.611411</p>
<p>-1.611411=mCAT
where m=2.18
C=4.184
AT=Tf-Ti
Ti=30</p>
<p>Tf=((-1.611411)/(2.18*4.184))+30
=30.18 C</p>
<p>is that correct?</p>
<p>No. Your units for the various specific heats are incorrect. You should not be able to multiply the specific heat and mass and get energy. </p>
<p>I don’t know exactly what your teacher wants because I’m not your teacher, but it seems reasonable to me that the goal of this experiment should be to find the temperature of the methane flame on your hand instead of the change in water temperature because it’s easier to record the temperature change of water than that of a flame.</p>
<p>If what I said is what your teacher wants, then the unknown should be the change in temperature of the flame. This means that all other quantities should be known or the equation can’t be solved. Since the unknown is on the flame side of the equation all of the water quantities should be known - it seems to me that the initial temperature of the water should be room temperature and the final temperature should be one you record with a thermometer (though this will be inaccurate as your body heat increases the water temperature as well. Maybe you were supposed to begin recording water temperatures after they have stabilized from your body warming the water up).</p>