Double-Check Homework: Specific Heat & Melting Ice

In summary, the first problem involves a 90 g block of unknown metal being heated to 86 degrees C and put into an insulated cup with 175 g of water at 23 degrees C. The final equilibrium temperature is 25.8 degrees C and the specific heat of the metal block is calculated to be 0.0904 cal/g degree C. In the second problem, a well-insulated cup contains 145 g of ice at 0 degrees C and 45 g of water at 75 degrees C is added. The amount of remaining ice is calculated to be 42.19 g and the final temperature in the cup is 0 degrees C.
  • #1
veronicak5678
144
0
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.
 
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  • #2
Looks good to me!
 
  • #3
OK, great. Thanks for looking it over!
 

1. What is specific heat and how is it related to melting ice?

Specific heat is the amount of heat energy required to raise the temperature of a substance by 1 degree Celsius. It is related to melting ice because as heat is added to ice, it increases the temperature of the ice until it reaches its melting point. At this point, the heat energy is used to break the bonds between the molecules of the ice, causing it to change from a solid to a liquid state.

2. Why is it important to double-check homework related to specific heat and melting ice?

Double-checking homework is important in any scientific field to ensure accuracy and understanding of the concepts being studied. In regards to specific heat and melting ice, double-checking can help catch any mistakes that may occur during calculations or understanding of the material, leading to a better understanding of the subject matter.

3. What is the formula for calculating specific heat?

The formula for calculating specific heat is Q = m x C x ΔT, where Q is the heat energy added, m is the mass of the substance, C is the specific heat, and ΔT is the change in temperature.

4. How does the specific heat of a substance affect its melting point?

The specific heat of a substance is directly related to its melting point. Substances with a higher specific heat require more heat energy to raise their temperature, making it more difficult to reach the melting point. On the other hand, substances with a lower specific heat require less heat energy to reach their melting point, making it easier to melt.

5. How does the specific heat of water compare to other substances?

Water has a relatively high specific heat compared to other substances. This means it requires more energy to raise its temperature compared to substances with lower specific heats. This is why water is often used to regulate temperature, such as in the human body, as it can maintain a relatively stable temperature despite changes in the surrounding environment.

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