Homework Help: chemistry

Posted by Yasha on Sunday, March 25, 2012 at 9:30pm.

If all the energy obtained from burning 1.23 pounds of propane (fuel value is 11.09 kcal/g) is used to heat 125.0 kg of water at an initial temperature of 21.8 °C, what is the final temperature?

Hint:
The heat, q, released by burning propane is absorbed by the water. Use the following formula to find the temperature change, ÄT,
q = m*c*(Change in temperature)
Where m is mass and c is specific heat

I've done it several different ways and I keep getting 21.8 for an answer and it says that is wrong.

chemistry - DrBob222, Sunday, March 25, 2012 at 10:38pm
Change 1.23 pounds to grams.
1.23 pounds x (453.6 g/lb) = ?
?g x 11,090 cal/g = calories of heat produced = y
y = mass H2O x specific heat H2O x (Tfinal-Tinitial).
I would use 125,000 for mass H2O. I get something like 70 C. You know it can't be 21.8. That's the starting temperature and you're adding bunches of heat. T must go up.

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