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Calorimeter experiment

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Calorimeter experiment:

Refer to attachments for full experimental design.

I need help with the following questions:
1. Why is it necessary to start this experiment with a large excess of ice in the metal ice container (the calorimeter)?

2. If all the ice melts when you were doing this experiment so at the end of the procedure you have a colorimeter full of water, how would this affect you result? Would you calculate a caloric value of your food to be higher or lower than true value?

4. Look up the density of water at 0 degrees celsius and explain if it would be acceptable to use the volume of the water melted (ml) instead of the mass of the water melted in your calculations.

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Answer 1)
The amount of energy that was harnessed in the nut and ultimately transferred into the melting of ice in the calorimeter is measurable based on how much water there was after the whole nut was burned. As a result, the amount of energy you can measure is directly related to how much water you collect, out of a total of however much ice there was at the beginning.

If there was too little ice, say, a single, small cube of ice, by the end of the burning we will have a puddle, but how do we ...

Solution Summary

The expert determines why it is necessary to start a calorimeter experiment with a large excess of ice in the metal ice container.

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See Also This Related BrainMass Solution

Calorimetry Lab - Enthalpy Change of a Chemical Reaction

Procedure:

1. Take a calorimeter from the glassware shelf and place it on the workbench.

2. Take a balance from the tools shelf and drop it on the calorimeter. Record the mass of the empty calorimeter.

3. Take a thermometer from the tools shelf and drop it onto the calorimeter. Record the temperature of the calorimeter.

4. Add 50 mL of 1.0M hydrochloric acid (HCl) to the calorimeter.

5. Add .15g of magnesium (Mg) to the calorimeter.

6. Immediately measure and record the maximum temperature displayed by the thermometer in the calorimeter.

7. Measure and record the mass of the calorimeter and its contents.

8. Repeat the experiment with a new calorimeter, using 50 mL of HCl and .25g of magnesium. Record the maximum temperature displayed by the thermometer in the calorimeter.

9. Repeat the experiment with a new calorimeter, using 50 mL of HCl and .35g of magnesium. Record the maximum temperature displayed by the thermometer in the calorimeter.

Questions:
1. Record the following for each of the three experiments:
(a) Mass of the empty calorimeter (g): ?
(b) Initial temperature in the calorimeter (C): ?
(c) Maximum temperature in the calorimeter from the reaction (C): ?
(d) Calculate deltaT as Tmaximum - Tinitial (C): ?
(e) Mass of the calorimeter and its contents after the reaction (g): ?
(f) Calculate the mass of the contents of the calorimeter (g): ?
(g) Calculate the moles of Mg reacted (MW=24.305 g/mole): ?

2. Calculate the heat released into the solution for the 3 reactions, according to: q(reaction) = Ccal * Delta T + mass(contents) * Cp (contents) * deltaT

(If you have not measured the calorimeter constant yet, assume that it is zero for this experiment.)

3. Find the molar heat of reaction for each experiment in units of Joules/(mole of Mg) by dividing the heat of reaction by the moles of Mg used.

4. Calculate and record the average molar heat of reaction from the three results.

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