Calorimetry, calculating for mass

In summary, the problem is to determine the amount of water needed to cool iron parts from 600°F to 200°F. The equation used is mass of iron parts * specific heat of iron * change in temp. of iron parts = mass of water * specific heat of water * change in temp. of water. To find the change in temperature of the iron parts, the initial temperature of 600°F is converted to 400°C. The correct formula for conversion of temperature units is applied, resulting in a change of 80.6°C for the water. The mass of the iron part used in the equation is assumed to be 1 kilogram. Therefore, 1 kilogram of iron parts will require 80.6 kilograms
  • #1
yoshi-chan7
8
0
Hi, here is the problem that I'm having trouble with.

It is desired to cool iron parts from 600°F to 200°F by dropping them into water that is initially at 55°F. Assuming that all the heat from the iron is transferred to the water and that none of the water evaporates, how many kilograms of water are needed per kilogram of iron?

I've used this equation:

mass of iron parts * specific heat of iron * change in temp. of iron parts = mass of water * specific heat of water * change in temp. of water

I first calculated the change in temperature of the iron parts and converted it to degree Celsius by 200F - 600F = 400F and then 400F*(5/9), which yields -222.

I plugged in the values as thus:

m*448 J/(kgC)* -222C = m*4186 J/(kgC)* 222C.

I've got a sneaking suspicion that it's because of the right side of my equation dealing with water. I think that somehow my scale is wrong, the 222C. But if all the heat released by the iron is transferred to the water with no loss, then the scale would be correct, wouldn't it?
 
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  • #2
Heat lost by the iron part = heat gained by the water.
1*448 J/(kgC)* 222C = m*4186 J/(kgC)* 80.6C.
 
  • #3
I don't understand how you got the 80.6C. Could you explain that, please?
 
  • #4
And also, why did the mass of the iron part become merely "1"? Wouldn't the mass be unknown?
 
  • #5
how many kilograms of water are needed per kilogram of iron?
Initial temperature of water 55F and final teperature of water is 200F
Convert this difference into C
 
  • #6
Thank you very much! I simply forgot to apply the formula for conversion of temperature units for the change in temperature. I understand perfectly now. Thank you~!
 

FAQ: Calorimetry, calculating for mass

What is calorimetry and why is it important in calculating mass?

Calorimetry is a scientific technique used to measure the amount of heat released or absorbed during a chemical reaction or physical change. It is important in calculating mass because it allows for the determination of the heat capacity of a substance, which is necessary for accurately calculating the mass of a substance.

How does calorimetry work to calculate mass?

Calorimetry works by using a calorimeter, which is a device that measures the heat of a chemical reaction or physical change. The calorimeter is used to measure the change in temperature of a substance and its surroundings, which can then be used to calculate the heat released or absorbed. By knowing the heat capacity of the substance, the mass can be calculated using the formula Q = mcΔT, where Q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

What are the units of measurement used in calorimetry?

The units of measurement used in calorimetry depend on the specific heat capacity of the substance being measured. In the SI system, the units for heat (Q) are joules (J), mass (m) is measured in kilograms (kg), and temperature (ΔT) is measured in degrees Celsius (°C). The specific heat capacity (c) is measured in joules per gram per degree Celsius (J/g°C).

How accurate is calorimetry in calculating mass?

The accuracy of calorimetry in calculating mass depends on several factors, such as the precision of the equipment used, the skill of the experimenter, and the complexity of the system being measured. Generally, with careful calibration and skilled experimentation, calorimetry can provide accurate results within a few percentage points of the actual mass.

Can calorimetry be used for any substance to calculate mass?

Yes, calorimetry can be used for any substance as long as its specific heat capacity is known. However, for some substances, such as gases, the calculations may be more complex due to changes in pressure and volume. Additionally, some substances may have a very low heat capacity, making it difficult to accurately measure the change in temperature. In these cases, other methods of mass calculation may be more suitable.

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