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!

Adding heat for final temperature

  1. Jan 16, 2008 #1
    1. The problem statement, all variables and given/known data
    How much heat is required to raise the temperature of 0.250kg of water from 20.0oC to 30.0oC?

    If this amount of heat is added to an equal mass of mercury that is initially at 20.0oC, what is its final temperature?

    2. Relevant equations


    3. The attempt at a solution

    for the first part i got
    this is wrong the correct answer was 1.05*10^4
    how did they get that answer?

    The second part i have so far
    it didnt say what the spefice heat of mercury was so i looked it up and it was 0.140

    please help with this
  2. jcsd
  3. Jan 16, 2008 #2


    User Avatar
    Homework Helper

    For the first part why are you using 1 for c? Look up the specific heat of water. Regardless, I don't see how you got 10.4725 from your equation for q. Is there a typo in there somewhere?
  4. Jan 17, 2008 #3

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    You have to be clear on your units. You appear to be working in calories and kg. If so, you have to use a specific heat for water in calories/kg deg not calories/g deg.

  5. Jan 17, 2008 #4
    i just said find the answer in joules
  6. Jan 17, 2008 #5

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    If you are using a specific heat of 1 for water you are working in calories/g. Kelvin. If you want the answer in joules you have to multiply the answer by 4.186 (ie. 4.186 J in one cal.). The specific heat for water in Joules/Kg K is 4186.

    Last edited: Jan 17, 2008
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Adding heat for final temperature