Eighth Grade Science

Question

Heat energy, Q, is calculated by multiplying the mass of the object in grams, m, by the change of temperature, mΔT, and the specific heat, Cp, of the material.

Q = mΔT(Cp)

1. Calculate the heat lost from the bread at each interval. Assume that the specific heat capacity of bread is 2.73 J/g °C.
2. Calculate the heat gained by the water at each interval. Assume that the specific heat capacity of water is 4.19 J/g °C.
3. Based upon the results in Questions 1 and 2, formulate a hypothesis regarding the transfer of heat between the bread and the water.
4. Identify at least one improvement that could be made to this experiment. Justify your response in two or more complete sentences.
5. What other household items could be used with your calorimeter? Do you expect to get a different result? Justify your response in two or more complete sentences.

Submission Requirements

Title of Lab:

Data Tables:

Questions/Results:

Upload your lab and data tables and results in the box below.

Answer 1

Hi, Abilyn,

These questions appear to be part of a lab in which you collected data. I'll assume that you obtained the mass (m), in grams, of the material in question (bread or water) and measure the temperature of both before and after in degrees C). I'm assuming you place warm bread into a beaker of water and measure the temperature change, since a "calorimeter" was mentioned as part of the experiment.

For question 2, you need the mass of water and its temperature change. Then use the given equation.

Q = mΔT(Cp)

The m is the grams of water, Cp is the heat capacity of water ( and the DeltaT is the temperature change. If you used 100 grams of water and saw a temperature rise of 10C, the equation would be:

Q (Energy in Joules) = 100g*(4.19J/gC)*(T1 - T2), where T1 and T2 are the temperatures (in C) for initial (T1) and final (T2) temperatures.

For question 1, I'll assume you measured the temperature drop in the water bath after putting in the bread. The procedure isn't clear, but if that is what happened, then you probably measured the water temperature before and after, as in question 2. If so, the heat gained by the water is the same as the heat lost by the bread. This assumes a "closed system," - one in which no heat is gained or lost to the surroundings. Not realistic, but it makes a good discussion on what can be improved.

Without knowing how the lab was conducted, these suggestions may not apply.

I hope it helps, however.

Bob