GC - Question: Heat lost, heat gained ???

ckmonster

Full Member
10+ Year Member
Sep 3, 2008
91
0
201
  1. Dental Student
This is from Destroyer...

An Unknown metal of 50 grams is initially at 100 ˚C and dropped into a beaker of 200 grams of water at 30 ˚C. The final temperature of the system is 40 C. Find the specific heat of the metal if the heat of water is 4.2 J/g C.

I get that we have to set the equations equal to each other, but i dont get how to properly set the temperatures

m(metal)*c*∆T = m(water)*c(water)∆T

so... (this is the set up given in the solutions)

(50) c (100 - 30) = (200) (4.2) (40-30)


Can someone shed some light PLEASEEEEE???
 

nze82

Full Member
May 15, 2009
1,922
3
0
CA
  1. Dental Student
This is from Destroyer...

An Unknown metal of 50 grams is initially at 100 ˚C and dropped into a beaker of 200 grams of water at 30 ˚C. The final temperature of the system is 40 C. Find the specific heat of the metal if the heat of water is 4.2 J/g C.

I get that we have to set the equations equal to each other, but i dont get how to properly set the temperatures

m(metal)*c*∆T = m(water)*c(water)∆T

so... (this is the set up given in the solutions)

(50) c (100 - 30) = (200) (4.2) (40-30)


Can someone shed some light PLEASEEEEE???
That's because you're not using the correct signs.
The metal loses heat, so the sign must be negative.
Water gains heat, so the sign must be positive.

-Qm = Qw

Now do the math! You should be able to come up with the correct answer.
 
This thread is more than 12 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.