Calorimetry: Calculate Unknown Mass of Water

In summary, by using the formula m = q/C*deltaT, the unknown mass of water at 20 degrees Celsius can be calculated as 31.5 grams when 42.1 grams of water at 80.9 degrees Celsius is added, resulting in a final temperature of 54.8 degrees Celsius. This calculation assumes a specific heat capacity of 4.184 J/g*C.
  • #1
Soaring Crane
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When 42.1 grams of water at 80.9 degrees Celsius are added to an unknown amount of water at 20 degrees Celsius. The final temperature of the mixture is 54.8 degrees Celsius. Calculate the unknown mass of water originally at 20 degrees Celsius.
For known mass:
q = (42.1 g)*(54.8-80.9 C)*(4.184 J/g*C) = 4593.0258 J
Now for unknown mass:
m = q/C*deltaT
4593.0258 J/(4.184 J/g*C)*(54.8-20 C) = 31.5448 = 31.5 g?
Thanks.
 
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  • #2
Any volunteers?

Thanks again.
 
  • #3
(Actually I believe by trying to bump your own threads you lose the chances of a reply - i.e. most people probably look for unreplied threads rather than ones that have been addressed)

Anyway, going through it, I think your calculations hold.
 

1. What is Calorimetry?

Calorimetry is a scientific method used to measure the amount of heat released or absorbed during a chemical reaction or physical change. It involves using a calorimeter, a device designed to measure heat transfer, to calculate the change in temperature of a substance.

2. How does Calorimetry work?

Calorimetry works by measuring the heat exchange that occurs between a known substance and an unknown substance. The known substance is used as a reference and its change in temperature is measured, while the unknown substance's change in temperature is calculated based on the heat exchange with the known substance.

3. Why is Calorimetry important?

Calorimetry is important because it allows scientists to accurately measure the energy changes that occur during a chemical reaction or physical change. This information is crucial in many fields of science, including chemistry, physics, and biology.

4. How is the mass of water calculated using Calorimetry?

The mass of water can be calculated using Calorimetry by measuring the change in temperature of a known substance, such as a metal, when it is placed in water. The change in temperature of the metal is then used to calculate the heat exchange with the water, and from there the mass of the water can be determined using the specific heat capacity of water.

5. What are the applications of Calorimetry?

Calorimetry has many applications in various fields of science, including measuring the calorie content of food, determining the energy efficiency of engines, and studying the heat capacity of materials. It is also used in industries such as food and pharmaceuticals to ensure product quality and safety.

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