1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Chemical Energetics

  1. Aug 16, 2007 #1
    1. The problem statement, all variables and given/known data
    The standard enthalpy change of combustion of propane (C3H8)
    is -2220kJ/mol. It requires 1.0J of energy to raise the temperature of 1.0g of air by 1.0K.

    Calculate what mass of propane needs to be burned to raise the temperature of the air in the balloon by 50K.

    2. Relevant equations

    3. The attempt at a solution

    For the air in balloon to raise by 50K,50J is needed I suppose.
    50/(mass of propane/44.0)=2220x10^3
    mass of propane = 9.91x10^(-4)g
    The answer given is (1.85x10^3)g.
    Can anyone correct me?
  2. jcsd
  3. Aug 16, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    You need to know the mass of air in the balloon or it's initial volume / temperature / pressure.
    Otherwise your answer is correct per g of air.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Chemical Energetics
  1. Chemical kinetics (Replies: 1)

  2. Chemical Nomenclature (Replies: 5)

  3. Chemical Kinetics (Replies: 1)