Name ____________________________________________ Date ______________ Period ____________ Heat Capacity BACKGROUND INFORMATION Heat, as you know by now, is measured in calories. A calorie is a unit of energy. It is defined as the amount of energy that it takes to raise one gram of water by one degree Celsius. We also learned that every substance has a property called specific heat. The specific heat is the number of calories that it takes to raise one gram of that substance by one degree Celsius. In this lab, we’re going to determine the specific heat of several different substances. PROCEDURE I. Obtain two different samples from the front bench. Note that there are metals and rocks. You may take any combination of them, but please make sure that you have two different samples. II. Use a triple-beam balance to find the mass of your two samples. III. Place your samples carefully in the pot of boiling water on the front bench. Note the time that you put them in on your data sheet. Heat the samples for 7 minutes. IV. While the samples are heating, obtain two polystyrene cups and two thermometers from the front bench. Pour 100 mL of ROOM TEMPERATURE water into each cup. Record the temperature of the water as your starting temperature on your data table. V. Once the samples have heated for 7 minutes, quickly but carefully move them from the boiling water to the cups you have prepared. Record the temperature in 30-second intervals until the temperature of the water no longer changes, usually about 5 minutes. VI. Carefully remove the samples from the water and return them to the front bench. Pour out your water and leave your cup upside-down on the edge of a sink to dry. VII. Use the data that you have collected to determine the specific heat of each substance that you tested. VIII. Determine the percent deviation of your values as compared to the accepted specific heat values. HYPOTHESIS Now that you know what you will be doing, and before you go any further, use the space below to write out a hypothesis. What do you think will happen? Which samples will have higher or lower specific heats, and why?

RESULTS Calories Calculation (find Q) Q = MCΔT Specific Heat Calculation (find C) Q = MCΔT Time (seconds) Temperature (°C) Percent Deviation Calculation (for specific heat) % deviation = difference from accepted value / accepted value Name ________________ Mass ________________ Calories Gained _____________ Specific Heat Calculated ____________ Accepted _____________ Percent Deviation _____________ SAMPLE A Start heating: Stop heating

Name ________________ Mass ________________ Calories Gained _____________ Specific Heat Calculated ____________ Accepted _____________ Percent Deviation _____________ SAMPLE B Calories Calculation (find Q) Q = MCΔT Specific Heat Calculation (find C) Q = MCΔT Time (seconds) Temperature (°C) Percent Deviation Calculation (for specific heat) % deviation = difference from accepted value / accepted value Start heating: Stop heating

CONCLUSIONS I. Which sample out of all those that you tested has the highest specific heat? Why do you think that is? II. Why was it important to mass the samples before putting them in the hot water? III. Describe the flow of heat throughout the experiment. Where did the heat come from, and where did it end up? IV. Look at your percent deviations. If they were very large or very small, what contributed to that? In other words, what was good about our experiment, and what aspects could be improved? V. Do you think that your results would have been different if we had used sand instead of water? How would your results have changed, and why? VI. Was your hypothesis supported by your data? Explain why or why not. VII. Do you think that the surface area of the samples has any effect on our experiment? What if we had used a very flat and thin piece of metal, instead of a cylinder? Make another hypothesis to state what you think would happen.