Phase Change

  • #1
Hoping someone could double-check for me....

Homework Statement



1) A 90 g block of unknown metal is heated to 86 degrees C and put in an insulated cup with 175 g water at 23 degrees C. At equilibrium, they are both 25.8 degrees C. What is the specific heat of the metal block?

2) A well insulated cup contains 145 g of ice at 0 degrees C. We pour in 45 g watwer at 75 degrees C.
a- Once equilibrium is established, how many grams of ice remain?
b- What is the final temp in the cup?




The Attempt at a Solution


1) c ( 90 g) (-60.2 degrees c) + 1 cal/g degrees C) (175 g) (2.8degrees C) = 0
c = 0.0904 cal/g degree C

2)
a- energy available to melt ice: 1 cal/ g Celcius (45 g) ( 75 degrees ) = 3375 cal
energy needed to melt ice: 145 g (80 cal/g) = 11600 cal
not all will melt

80 cal /g (mass melted) = 3375 cal
mass melted = 42.19 g

b- Temp is 0 since there is still ice.
 

Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
11
Looks good to me!
 
  • #3
OK, great. Thanks for looking it over!
 

Related Threads on Phase Change

  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
0
Views
3K
  • Last Post
Replies
3
Views
8K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
4
Views
3K
  • Last Post
Replies
6
Views
4K
Top