The density of water, given in class during the duration of the experiment, is 1 gram per milliliter. So that was taken and multiplied times the 100 mL of water used in the experiment.
Percent Uncertainties
Volume of water- (.5 / 100) ● 100 = .5 %
Temperature of distilled water- (.5 / 24.2) ● 100 = 2.07%
Mass of copper- (.001 / 43.027) ● 100 = .0023%
Temperature of copper- (.5 / 95.1) ● 100 = .53%
Final temperature of water- (.5 / 28.9) ● = 1.73%
Change in temperature in finding quantity of heat of water- (1 / 4.7) ● 100 = 21.3 %
Change in temperature in finding specific heat of copper- (1/66.2) ● 100 = 1.5%
The absolute uncertainty was divided by the experimental value then multiplied by 100 in order to obtain the percent error for each of volume, temperature, mass, etc.
Finding the Quantity of Heat “q” of water
q = mc∆t
qH2O = (100 + .5 % g) (4.18 J/g ● C°) (28.9 + 1.73% C° - 24.2 + .5% C°)
qH2O = (100 + .5 % g) (4.18 J/g ● C°) (4.7 + 21.3% C°)
qH2O = 1964.6 + 21.8 % J (not correct sig figs)
qH2O = 1964.6 + 20 % J (correct sig figs)
The formula q = mc∆t is used to find the quantity of heat of water. The mass of the water was multiplied times the specific heat of water and then multiplied times the change in temperature (final temperature – initial temperature).
Finding Specific Heat “c” of copper
qcopper= -1964.6 + 21.8 % J
q = mc∆t
-1964.6 + 21.8% J = (43.027 + .0023% g) (c) (28.9 + 1.73% C° - 95.1 + .53 C°)
-1964.6 + 21.8% J = (43.027 + .0023% g) (c) (-66.2 + 1.5% C°)
-1964.6 + 21.8% J = (-2848.3874 + 1.5023% g● C°) (c)
c = .690 + 23.3023% g● C° (not correct sig figs)
c = .690 + 20% g● C° (correct sig figs)
The formula q = mc∆t was used here to find the specific heat of copper. The qcopper is just the inverse of the qH2O so it was -1964.6 + 21.8% J. Then the mass of copper was plugged in and multiplied times the change in temperature (final temperature – initial temperature). The product of these two things were then divided from the qcopper to get the specific heat, “c”, of copper.
Percent error
(| Literature value – experimental value| / Literature Value) ● 100
(|.385 J/ g ● C° – .690 J/ g ● C°| / .385 J/ g ● C°) ● 100 = 79.2%
To find the percent error, it is the absolute value of the literature value (.385 J/ g ● C°) – the experimental value (.690 J/ g ● C°). Then divide that by the literature value (.385 J/ g ● C°) and multiply that by 100 to change it into a percent.
Overall Experiment:
Average of Specific Heat in All Three Trials
.690 + 20% J/ g ● C°
.692 + 20% J/ g ● C°
+ .596 + 30% J/ g ● C°
.659 + 23.33% J/ g ● C° (not correct sig figs)
.659 + 20% J/ g ● C° (correct sig figs)
The average was found by taking the calculated specific heat of copper in each trial. The average of the three specific heats was found to be .654 + 20% J/ g ● C°.
Average Percent Error
(| Literature value – experimental value| / Literature Value) ● 100
(|.385 J/ g ● C° – .659 J/ g ● C°| / .385 J/ g ● C°) ● 100 = 71.2%
To find the percent error, it is the absolute value of the literature value (.385 J/ g ● C°) – the experimental value (.659 J/ g ● C°). Then divide that by the literature value (.385 J/ g ● C°) and multiply that by 100 to change it into a percent.
Presentation
Processed Data
Calculated Data
Conclusion and Evaluation
Conclusion
Indicated above is the experimental value or the average specific heat of the copper which was calculated in this experiment to be….. .690 + 20% (J/ g ● C°). Of course the actual value of copper also known as the literature value has a specific heat of …..385 (J/ g ● C°). According to calculations the total overall percent error of the entire experiment was……71.2%. The percent wrote will de discussed in the following sections to show why it was so great in the outcome of this experiment.
Limitations of Experimental Design
There were several limitation s in the overall experimental design. The design the transferring was horrible because it allowed massive heat loss which flawed the outcome and accuracy of the data. When stirring the distilled water the concept of having the consistency during the entire experiment was not present because it was not measured which caused error in the data. Since the percent error was so substantially high for this experiment (2344) this lead to not only systematic error but also random error as well. 100mL of distilled water was to be measured by the graduated cylinder which has been shown not to be the most accurate way to measure a substance. Time was not properly collaborated when timing the duration of how long the copper bathed inside the boiling water. It was not measured to seconds. Also the stirring of the distilled water within the cup with copper was not timed. The digital scale already displayed an uncertainty which varied the data. The specific heat of copper was not accurately derived because the transfer of copper lost heat.
Suggestions for Improvement
Suggestions of improvement include the use of a different piece of equipment to mea use out the volume since the graduated cylinders have an uncertainty of + .5 which was rather unreliable. Another suggestion of improvement is to calculate the duration of time the copper is to ay within the boiling water down to a second. Be sure to stay consistent between trials. Lastly, the transfer of copper from coiling water to distilled water could be measured in ten second intervals to allow all trials the same amount of heat to escape.
