University:
California State University, Chico
Course:
PHYS 202A | General Physics I
Academic year:

2021
Views:

144

Pages:

14
Author:

Hallie Randolph

Lab Report #1 Specific Heat I. Introduction The specific heat of a substance is the amount of heat required to raise the temperature of one gram of one of the substance by 1℃. The goal of this lab experiment was to find the specific heat capacity of a substance given as a sample in lab. The goal was to find the specific heat capacity of the given substance and identify it to be one of the common metals specified in a table in our lab assigned paper. II. Description of Experiment The equipments we used for this experiment were the given sample, calorimeter, thread, ice, water, thermometer and weighing machine. - First of all, the mass of the given sample was recorded and placed in a cup filled with ice for a couple of minutes. - A calorimeter’s mass was measured and was filled with room-temperature water until ¾ filled. The initial temperature of the water and calorimeter was recorded. - Also, the mass of water was recorded. - After placing the given sample in ice for 4-5 minutes, it was taken out and dried with paper towel. -Immediately after that, it was placed inside the water in the calorimeter assuming the initial temperature of ice is 0℃. - The temperature was then monitored until it reached a steady value or the equilibrium state and was recorded. - The experiment was repeated 2 more times, each with new volume of water in room temperature. - The recorded values were then used to calculate the specific heat of the sample as below. III. DATA: Run # Mass of Tsi substanc (0℃) Tf ΔTs Mass of Twi Tf ΔTw (℃) (℃) water (℃) (℃) (℃) e (ms) (mw) 1 0.080 0 16.9 16.9 315 17.8 16.9 -0.9 2 0.080 0 16.8 16.8 308 17.7 16.8 -0.9 3 0.080 0 16.8 16.8 310 17.8 16.8 -1 IV. Analysis: Cs was calculated using following formula: Cs = -( mwcwΔTw)/ (msΔTs) Where cw= 4185.5 J/ kg ℃ (standard value) ● Run #1: cs= 877.654 J/ kg ℃ Run #2 : cs= 863.259 J/ kg ℃ Run #3 : cs= 968.75 J/ kg ℃ ● Average cs= 903.221 J/ kg ℃ ● Standard deviation (𝝈) = 57.286 (Looking at the table of specific heat values of common metals, our sample is very close to that of aluminium.) ● Known value of specific heat of aluminium c s = 901 J/ kg ℃ ● 95% confidence interfere = c s ± 2𝝈/√ ❑ = 901 ± 66.14 J/ kg ℃ Our calculated value is well in the range of 95% confidence interfere. ● % Error = 0.24 ● Possible sources of error : -Assuming the metal to be 0℃ might be a source of error. -When drying of the sample, human hand contact may increase its temperature. ● Ways to reduce error: - Keeping the sample for a longer amount of time and using the temperature of metal in calculations instead of assuming it to be 0℃. - Using caution to not touch the sample while drying it off. V. CONCLUSION: ● Yes I was able to achieve the goal as I was able to identify the metal to be aluminium with minimum error possible and within 95% confidence interfere. ● From this experiment, we can conclude that the sample given was aluminium. ● Assumptions used in the calculations are -Assuming sample metal to be 0℃. - Metal was assumed to be pure and not mixed with other elements - Calorimeter was assumed to be perfectly insulated. ● Possible sources of error: - Sample metal hadn’t reached 0℃ temperature when it come in contact with water. - Calorimeter wasn’t perfectly insulated giving out heat to external surroundings.