Specific Heat Capacity Lab

Specific Heat Capacity Lab

I. Title: Specific Heat Capacity Lab II. Purpose: To determine the specific heat capacity of the metal washer and identify the type of metal used.

III. Background: Brainstorm a list of background information that would be included in your lab

Which explanation of a calorimeter would you prefer to receive? 1. A device that keeps heat in. 2. A device used in a lab to keep energy from entering or exiting the system. 3. A calorimeter is a device for measuring the heat developed during a chemical reaction, and for calculating the heat capacity of materials (Britannica). In this lab, two styrofoam cups will be used as a crude calorimeter. The two cups will keep the energy from entering or exiting the system causing the net energy within the system to remain constant. In other words, the energy given up by the washer should be numerically equal to the energy gained by the water.

IV. Materials List: Calorimeter 4 Washers Distilled Water (approximately 1.5 L) Electric Balance Thermometer Ring Stand Iron Ring Hot Plate One 2 ft piece of string 1 – 100 mL graduated cylinder (1) 1000 mL Beaker

V. Procedure: 1. Put on apron and goggles. 2. Fill 1000 mL flask with approximately 900 mL of distilled water and place on hot plate. Turn hot plate to med/high temperature to allow water to boil. 3. Attach iron ring to ring stand and place ring stand next to 1000 mL flask so that the front edge of the iron ring is above the beaker. See diagram 1. Make sure the end of the iron ring lines up with the top of the flask Iron Ring 1000 mL Flask Hot Plate Diagram 1 (Bjorge) Ring Stand

4. Obtain a metal washer. Using electric balance, record the mass of the washer. 5. Fill a 100 mL graduated cylinder with 50 to 100 mL of distilled water. Measure and record volume with appropriate precision. Pour water into the calorimeter. 6. Measure and record the temperature of the water in your calorimeter. 7. Wait for the water in the 1000 mL flask to boil. 8. Tie a string to the washer and hang the washer through the iron ring so that the washer is inside the boiling water. Keep the washer in the water for 5 minutes. Make sure that the washer is completely submerged. 9. Take the temperature of the boiling water and record as the initial temperature of the washer. 10. As quickly and safely as possible, move the metal washer from the boiling water to the calorimeter. Cover the calorimeter with the lid and insert thermometer through the preexisting hole into the water.

11. Wait for the temperature to stabilize. The temperature is stable when there are 10 seconds or more between temperature changes. 12. Record the stable temperature of the calorimeter. 13. Pour water down the drain and dryer out calorimeter. 14. Repeat steps 4 – 13 twice. Once with a different washer and once with two different washers. 15. Clean up lab station. Make sure all water is poured down the sink and any spilled are wiped up.

VI. Data and Observations: Qualitative Observations – Boiling water had white flecks in it that resembled tiny pieces of tissue paper. 4 cracks in the lid of the calorimeter. In trial 2, the water took a longer time to stabilize to a temperature.

Data (Quantitative Observations) Metal Washers Trial 1 Mass or volume Initial Temperature ( C) Final Temperature ( C) 29.3 g 51.6 mL 100.1 23.7 19.1 23.7 4.184 Specific heat (J/g C) Metal Washers Trial 2 Mass or Volume Initial Temperature ( C) Final Temperature ( C) Specific heat (J/g C) Water in Calorimeter Water in Calorimeter 32.1 63.2 mL 100.7 24.1 19.3 24.1 4.184

Trial 3 Mass or volume Initial Temperature ( C) Final Temperature ( C) Specific heat (J/g C) Metal Washers 61.8 g 100.6 26.7 Water in Calorimeter 76.0 mL 19.2 26.7 4.184

VII. Calculations What is needed for a good calculations section?

Calculations to Include Energy determination for water for each trial Specific Heat Capacity of the washer Average “S” of washer Percent Error for “S” of washer

VIII. Conclusion: Conclusions: The conclusion is a very important part of the formal lab report. This is where you demonstrate your understanding of the procedures and your ability to analyze the results of your experiment correctly. You should correctly interpret and summarize all observations, data, and calculations included in the lab. Cite data and calculations using specific examples to justify and support your conclusions. The conclusions should be linked directly to the objectives and/or questions stated in the purpose of the lab. A good conclusion should be several paragraphs and demonstrate a thorough understanding of the experimental results and their implications. Be honest about the limitations of your experiment and your confidence in your conclusions. For student-designed experiments, analyze your experimental design and offer suggestions for improvement. Be sure to include a paragraph explanation of sources of error and inaccuracies in your results are to be included here. Discuss what your group may have done and how it specifically caused your results to be as they are. For example: The density of iron should be 7.86 g/cm3. If during a density experiment, your group found the density of iron to be 8.91 g/cm3 instead, discuss errors which would cause your density calculations to be too high. Make it clear how each error would have driven the density to be a higher value. It is not appropriate to say “we must have misread the graduate or measured wrong”. If you did this, your group should repeat the experiment! The conclusion is something you write individually and should be in your own words.

Error What is a reasonable source of error for a low specific heat capacity?

IX. Work Cited It is impossible to complete a lab well without having used a definition or diagram from an outside source. "calorimeter." Encyclopædia Britannica. 2010. Encyclopædia Britannica Online. 20 Feb. 2010 http://www.britannica.com/EBchecked/topic/901 54/calorimeter .