- #1
torquemada
- 110
- 0
Homework Statement
A 5.00-g sample of aluminum pellets (specific heat capacity = 0.89 J/°C · g) and a 10.00-g sample of iron pellets (specific heat capacity = 0.45 J/°C · g) are heated to 100.0°C. The mixture of hot iron and aluminum is then dropped into 96.5 g of water at 23.5°C. Calculate the final temperature of the metal and water mixture, assuming no heat loss to the surroundings.
Homework Equations
(the specific heat of a substance *Joules)/(degrees C * # of grams) = 1
The Attempt at a Solution
I first found the Energy in Joules in all 3 substances. For Al I got 561.797J, Fe 2222.22J, H2O 542.5239J
Then for the entire mixture the total J is 3326.5409 and the Mass total is 111.5g, and I need to find Temperature. I'm stuck at trying to find the Specific heat of this mixture. In my first attempt I got 3.6979 by adding up the specific heats of each substance by % of Total Mass. Then with that I calculated Temperature and got around 110 degrees C which was wrong according to WebAssign. My second attempt I just used the Specific heat of water 4.18 and I got around 125 C which was also wrong. I am leaning toward the first method to get Significant heat but maybe my calcs are off or I rounded wrong somewhere because WebAssign doesn't really have flexibility when it comes to rounding/sig figs. Or maybe a fundamental aspect of my approach to this problem is wrong? Just a shot in the dark but I tried adding the specific heats without regard for the mass % and I got 5.52 which gave me a Temperature of 164.7 C - i have a feeling this is an incorrect approach but I'm just throwing it out there so you know I thought of it. Thx in advance for any help
Last edited: