Finding the mass of iron using the heat equations

In summary, the task is to calculate the mass of iron at 100C that will cause 20.0 kg of water to change temperature from 16C to 18C. The specific heat (C) for iron is 460 J/kg C and for water is 4190. The equation used is q1+q2=0, and q=mct. By setting q1=-q2, the equation becomes mct=-mct. Solving for m, we get 3.5 kg as the mass of iron. The final temperature of the iron and the temperature change are not given, making it difficult to calculate without the mass being given. In order to determine the final temperature of the iron, it
  • #1
math989
5
0

Homework Statement


Calculate themass of iron at 100C that causes 20.0 kg of water to change temperature from 16C to 18C. C of iron is 460 J/kg C. The C for water is 4190. [/B]

Homework Equations


q1+q2=0
q=mct[/B]

The Attempt at a Solution


q1=-q2
mct=-mct
20(4190)(2)=-m(460)(100)
167600=46000m
3.5=m
 
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  • #2
What's the final temperature of the iron? What was the temperature change of the iron?

Chet
 
  • #3
That's my main issue right now because that is not given to me and I am having a hard time trying to figure how one would do that without the mass being given.
 
  • #4
math989 said:
That's my main issue right now because that is not given to me and I am having a hard time trying to figure how one would do that without the mass being given.
If you put something hot in contact with something cold and let them equilibrate with one another, do they (a) reach different final temperatures or (b) reach the same final temperature?

Chet
 
  • #5

The mass of iron needed to cause a change in temperature of 2 degrees in 20 kg of water at 100°C is 3.5 kg. This calculation was done using the heat equation, which states that the heat gained by the water (q1) is equal to the heat lost by the iron (q2). By rearranging the equation to solve for the mass of iron (m), we can plug in the known values for the specific heat capacities of iron and water, as well as the change in temperature and the initial and final temperatures of the water. This calculation can also be confirmed by using the specific heat capacity of iron to calculate the heat gained by the water and comparing it to the heat lost by the iron. This type of calculation is important for understanding how heat is transferred between objects and how different materials respond to changes in temperature.
 

1. How do you find the mass of iron using heat equations?

To find the mass of iron using heat equations, you first need to measure the amount of heat energy absorbed by the iron. This can be done by heating the iron and measuring the temperature change using a thermometer. Then, you can use the specific heat capacity of iron and the equation Q = mcΔT, where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. Rearrange the equation to solve for mass (m = Q/cΔT) and you will have the mass of the iron.

2. Why is it important to use heat equations to find the mass of iron?

Heat equations are important because they provide a precise and accurate method for determining the mass of a substance. They take into account the specific heat capacity of the material, which can vary between substances, and the change in temperature, allowing for a more accurate calculation of mass.

3. Can you use any type of iron to find the mass using heat equations?

Yes, you can use any type of iron to find the mass using heat equations. The specific heat capacity of iron is the same for all types of iron, so the calculation will be accurate regardless of the type of iron used.

4. What are the limitations of using heat equations to find the mass of iron?

One limitation of using heat equations to find the mass of iron is that it assumes the heat energy is the only factor affecting the change in temperature. In reality, there may be other factors, such as heat loss to the surrounding environment, that can affect the accuracy of the calculation.

5. Are there any other methods for finding the mass of iron?

Yes, there are other methods for finding the mass of iron, such as using a balance to measure the physical weight of the iron. However, using heat equations is often preferred because it does not require direct contact with the iron and can be used for objects that are difficult to weigh, such as small or irregularly shaped pieces of iron.

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