Calorimetry- how do I know the final temperature?

In summary, the experimenter is trying to figure out how to calculate the mass of a hot metal when it is put into water. He is unsure of how to know when the experiment has reached thermal equilibrium. The variables that he is unsure of are the temperature of the water and the metal, as well as the manipulated variable.
  • #1
jumbogala
423
4
I am doing a lab in which I have to come up with my own procedure. The lab involves putting a hot metal into water, then using calorimetry calculations to find the mass of the metal. (The metal is hotter than the water).

What I don't understand is how you know when to stop taking the final temperature of the water + metal mixture. I would assume it's when the mixture has reached thermal equlibrium. But at that point won't the whole mixture lose heat to the surroundings because the calorimeter isn't perfect?

So how do I know when it's reached thermal equilibrium if it will always be losing heat to the surroundings?

Also on the list of materials, it says "reggae". Nothing in the dictionary besides reggae music. Any ideas?
 
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  • #2
Assume that the calorimeter is perfect. The water will initially be cold and slowly warm up until the temperature changes no more. What will be that temperature if you know the heat capacity of the water and the metal and their respective temperatures before the experiment?

The reggae is probably there as a joke... Turn on some music.
 
  • #3
After the temperature stops rising, it will start to fall, I guess. So the highest recorded temperature would be the final temperature... right? So you would have -mct = mct, solving for m. I think I get it, thanks!

Also our teacher wants us to include variables. I understand that controlled variables will be things like measuring the temperature of the water the same way each time, etc.

But since this is an experiment that deals with calculations, couldn't the manipulated variable be different each time? And I wouldn't think there would be a responding variable since the mass of the metal doesn't ever change.

Am I right about that or are there variables that I'm missing?
 

Related to Calorimetry- how do I know the final temperature?

1. What is calorimetry?

Calorimetry is the scientific method of measuring the amount of heat released or absorbed during a chemical reaction or physical change. It involves measuring the temperature change of a substance or system before and after the reaction or change takes place.

2. How is the final temperature determined in calorimetry?

The final temperature in calorimetry is determined by measuring the initial temperature of the substances involved, calculating the change in temperature after the reaction or change, and then adding this change to the initial temperature. This gives the final temperature of the system.

3. What are the key factors that affect the accuracy of calorimetry?

The accuracy of calorimetry is affected by several factors, including the insulation and heat capacity of the calorimeter, the precision of temperature measurements, and the amount and type of reactants used. It is important to control these variables to obtain accurate results.

4. Can calorimetry be used to determine the heat of a reaction?

Yes, calorimetry can be used to determine the heat of a reaction. By measuring the temperature change and using the known heat capacity of the calorimeter, the heat released or absorbed by the reaction can be calculated using the formula Q = mcΔT, where Q is the heat, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.

5. Are there any limitations to using calorimetry?

Yes, there are some limitations to using calorimetry. One limitation is that it assumes that all heat released or absorbed by the reaction is transferred to the surrounding environment, which may not always be the case. Additionally, the process of measuring and transferring substances into the calorimeter can introduce errors. It is important to carefully control and account for these limitations in order to obtain accurate results.

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