LAB 10

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Report102.docx

Experiment 10:

Student name:

Pre-lab section:

1) Introduction: Explain the theory behind this experiment in a paragraph between 150 and 250 words. (2 Points)

Suppose you are using external resources; include the reference. It would be best if you had any relevant formulas and explanations of each term. You may use the rich formula tools embedded here. 

2) Hypothesis: In an If /Then statement, highlight the purpose of the experiment. (1 point)

Post-lab section:

3) Attach an image of your signed data sheet here. (1.5 Points)

4) Attach your analysis here, including any table, chart, or plot image. (7.5 points)

This should include:

Table 1: 1.5 points

Table 2: 1.5 points

Table 3: 1.5 points

Table 4; 1 point

Table 4: 1 point

Table 6: 1 point

5) Attach the image of samples of your calculation here. (1 point)

6) In a paragraph between 100 and 150 words, explain what you Learn. What conclusion can you draw from the results of this lab assignment? (2 points)

7) In one sentence, compare the results of the experiment with your Hypothesis. Why? (1 point)

8) Attach your response to the questions in the lab manual here. (4 points)

Question 1: 1 point for each part, 0.5 points

Question 2: 1 point

Question 3: 0.5 points

Question 4: 1.5 points

Exp10PHY2048LExp10DataandInstructions28129.pdf

Provided data for Exp 10 and instructions for data analysis and lab report

1. Provided data for Exp 10

Table 1 Measured data for specific heat of aluminum

aluminum m (g) 1T (C)

Wm (g) WT (C)

2T (C) c (cal/gC) (measured)

Trial 1

21.17

100

100

19.4

22.7

Trial 2 22.4

Trial 3 22.1

Table 2 Measured data for specific heat of steel

steel m (g) 1T (C)

Wm (g) WT (C)

2T (C) c (cal/gC) (measured)

Trial 1

66.67

100

100

19.4

23.9

Trial 2 24.0

Trial 3 24.3

Table 3 Measured data for specific heat of brass

brass m (g) 1T (C)

Wm (g) WT (C)

2T (C) c (cal/gC) (measured)

Trial 1

114.17

100

100

19.4

26.3

Trial 2 25.5

Trial 3 26.2

2. Instruction for data analysis in Exp 10

(a) Use the measured data in Tables 1 to 3 to calculate the measured specific heat (including the average

value and deviation) of the three metals. Record the results in Tables 4 to 6 (in the lab manual).

(b) Calculate the % errors between the measured and the literature values of specific heats of the

three metals. Record the results in Tables 4 to 6 (in the lab manual).

3. Instructions for Exp 10 lab report

(a) Tables 1 to 6 should be included in your lab report.

(b) It is required that the answers or solutions to the 4 questions (at the end of the lab manual)

should be included in your lab report.

(c) The required other contents and format for your lab report can be found in the syllabus

PHY2048LExp10Theory2.pdf

Concept behind the experiment

Conservation of Energy: For an isolated system, total energy of system remains constant. Only transfer of energy occurs among the components of the system.

Applying to heat energy: If a hot (at higher temperature) and cold (at lower temperature) body insulated away, they exchange heat to reach a final equilibrium temperature, that is same for both bodies. When equilibrium is reached, we have: Total heat energy lost by hot body while reaching equilibrium = Total heat energy gained by cold body while reaching equilibrium

Key Idea for experiment: Take a body at 100 ̊C , immerse in water at room temperature and insulate this system and let it reach equilibrium through exchange of heat energy.

Specific heat of a material

Definition: The amount of heat needed to change the temperature of an object of 1 unit mass, made of some material, through 1 unit temperature is said to be the specific heat c of the material. It is constant for a material. The amount of heatΔQ needed to change temperature by ΔT

of massm of a substance is then: ΔQ = cmΔT (1) In c.g.s system, unit of heat is specific heat is cal /g ̊C . In SI

system, unit of specific heat is J /kg K . We will use the c.g.s system. It takes ΔQ = 1cal amount of heat to raise temperature of 1g

of water from 14.5 ̊C to 15.5 ̊C . Hence, specific heat of water

is: cw = ΔQ mΔT

= 1cal

(1 g)(1 ̊C ) = 1cal /g ̊C .

Experimental setup and quantities

We have the following different quantity measurements needed for the experiment:

Mass of water in cup: mw = 100 g Initial temperature of water in cup:Tw Specific heat of water: cw = 1cal /g ̊C Mass of object: m Initial temperature of object: T

1 = 100 ̊C

Specific heat of object: c Final equilibrium temperature of water and object in cup after heat exchange: T

2

Deriving equation

Heat lost by object to reach equilibrium: ΔQobject = cm(T

1 − T

2 ) . (2)

Heat gained by water in cup to reach equilibrium: ΔQH

2 O = cwmw(T 2 − Tw) (3)

According to conservation of energy, we then have: ΔQobject = ΔQH 2O

(4)

Then, substituting Eqn. (2) & (3) in (4), we get: cm(T

1 − T

2 ) = cwmw(T 2 − Tw)

→ c = mw(T 2− Tw)

m(T 1 − T

2 ) cw (5)

End of Theory