Calorimetry Lab 2 Results

Gizmos Calorimetry Lab ALL Answers 1. The Latin word calor means "heat," and meter comes from the Greek word meaning "to measure." What do you think a calorimeter does? Measures the changes in heat, which indicates the calories 2. Where have you heard the word calorie before? What do you I have heard of calories from food and know from chemistry that it think a calorie is? is the amount of energy needed to raise the temperature 1. On the SIMULATION pane, select Copper. Use the slider to set its Mass to 200 g. Set the water mass to 200 g. Check that the Water temp is set to 30.0 °C and the copper's Temp is 90 °C. Select the GRAPH tab, and click Play A: 35.06 °C B: it went down by 54.94 °C C: it went up by 5.06 °C A. What was the Final temperature of the copper and the water? B. How much did the temperature of the copper change? C. How much did the temperature of the water change? Water has a greater specific heat capacity because the temperSpecific heat capacity can be described as a substance's resisature of the water only changed by 5.06 °C, unlike the copper's tance to temperature changes. Which substance has a greater change of 54.94 °C. The water resisted temperature change more specific heat capacity, copper or water? Explain. than the copper. 1. Predict: In the Gizmo warm-up, you saw how 200 g of 90 °C copper transfers heat to 200 g of 30.0 °C water. A: I think increasing the water's mass will decrease the final temperature. A. How do you think increasing the water's mass would affect the B: I think decreasing the copper's mass will decrease the final final temperature? temperature. B. How do you think decreasing the copper's mass would affect C: Increasing the copper's initial temperature would increase the the final temperature? final temperature, and decreasing the copper's initial temperature C. How do you think increasing or decreasing the copper's initial would decrease the final temperature. temperature would affect the final temperature? 2. Collect data: Use the Gizmo to determine the final temperature for each set-up listed below. Record your results in the tables. In the first table, you experiment with changing the water's mass. In https://drive.google.com/file/d/1wSI-xpNOWEL9FapyaMz2gPVthe second table, you change the copper's mass. In the third table, AbcbJBVS_/view?usp=drive_link you change the initial temperature of the copper. The first row of each table has been completed for you. 3. Analyze: For each factor listed in the chart below, explain how A: The final temperature was lower due to the water's capacity the final temperature was being higher changed and why you think that change occurred. B: The final temperature was lower due to the amount of heat being lower initially because of the decreased mass having lower energy A. What was the effect of increasing the water's mass? C: When the initial temperature was raised, the final temperature B. What was the effect of decreasing the copper's mass? was higher due to the increase of heat energy and vice versa, for C. What was the effect of changing the initial temperature of the the initial temperature was lowered copper? 4. Draw conclusions: The amount that the water's temperature increases depends on the mass of the water and the amount of heat energy in the copper. A. How does changing the initial mass of the copper affect how much heat energy it has? B. How does changing the initial temperature of the copper affect how much heat energy it has? A: the larger the amount of mass, the greater amount of heat energy it will have B: the higher the initial temperature, the greater amount of heat energy it will have 5. Apply: Many gyms and health clubs have steam saunas, which are small steam-filled rooms. Traditionally, steam saunas have a container of heated rocks. A small ladle of water is poured on the A: the heat from the rocks transfers to the water, so the water rocks in order to make the steam. vaporizes and creates steam B: if the amount of water is too large, then the temperature of the A. Use what you have learned so far about heat transfer to explain rocks will be affected too much and cool down the rocks instead how hot rocks can be used to make steam? of using the rock's heat to make steam B. Why do you think only a small ladle full of water is poured on the rocks at one time? 1/4 1. Explain: How do you think you can use the calorimeter to you can compare the results of the different substances with the compare the specific heat capacities of the substances listed on same temp and mass for all of them the Gizmo? The substance with the highest specific heat capacity will be the one that leaves the highest final temperature. I think the substance with the highest specific heat capacity will be ice because it is water but in a different phase 2. Predict: Which substance do you think will have the highest specific heat capacity? Why? Granites final temperature: 39.53 °C 3. Experiment: Use the Gizmo to determine the final temperature Leads final temperature: 31.78 °C for each set-up listed below. Record your results in the table. The first row has been completed for you. https://drive.google.com/file/d/1wSI-xpNOWEL9FapyaMz2gPVAbcbJBVS_/view?usp=drive_link 4. Analyze: Of the three substances, which caused the largest the lead had the largest temperature change, indicating that it has temperature change in the water? What does this indicate about the lowest specific heat among the substances because it had the its relative specific heat capacity? lowest resistance to temperature change 5. Interpret: Remember that specific heat capacity is a measure of a substance's resistance to temperature change. The more resistant a substance is to temperature change, the higher is its specific heat capacity. granite, copper, lead Rank the three substances in order of their specific heat capacities, from highest to lowest. 6. Predict: How do you think the specific heat capacity of ice will I think the specific head capacity of ice will be higher than granite, compare to that of copper, granite, and lead? copper, and lead 7. Experiment: Deselect Lead and select Ice. Use the default values for Temp (-30 °C) and Mass (50 g). Set the Water temp to A: 32.26 °C 60 °C and the Water mass to 200 g. B: I think the line disappears because the ice's melting point is 0°C so the substance went through a phase change into water when A. What was the final temperature? melting, so the substances were the same after the ice melting B. What do you think is happening when the ice line on the graph C: a 27.74 °C temperature change is at 0 °C for a long period of time? Why do you think the line D: ice has the highest specific heat (has a lot more resistance to disappears after that? change) ice changed the temp of water way more than the other C. How much of a temperature change did the water experience? substances, even with a significantly lower mass D. How does this change in the water's temperature compare to the change caused by the other substances you tested? 8. Extend your thinking: A lot of energy is needed to heat a substance with a high specific heat capacity. However, even more energy is needed to cause a phase change (such as the melting A: 15.60 °C of ice). Click Reset. Set the ice's Temp to -100 °C and its Mass to B: yes, I think all of the ice melted because the line on the graph 50 g. Set the Water temp to 50 °C and Water mass to 200 g. representing ice still stopped/disappeared at the ice's melting point of 0°C A. What was the final temperature? C: the water's temperature changed from 50 °C to 25 °C while the B. Do you think all the ice melted? Explain. ice was melting, making it a 25 °C change. the water's temperature C. Look at the GRAPH. The graph shows two separate stages: the changed from 25 °C to 15.60 °C while the ice was heating (after heating of the ice and then the melting of the ice. How much did the ice was completely melted), making it a 9.40 °C change. the water's temperature change while the ice was heating? How D: this experiment demonstrated ice's high specific heat capacity much did it change while the ice was melting? because it showed ice's high resistance to temperature change D. How did this experiment demonstrate ice's high specific heat capacity? 1. Solve: When you mix two substances, the heat gained by one substance is equal to the heat lost by the other substance. Suppose you place 125 g of aluminum in a calorimeter with 1,000 g of water. The water changes temperature by 2 °C and the aluminum changes temperature by -74.95 °C. A. Water has a known specific heat capacity of 4.184 J/g °C. Use the specific heat equation to find out how much heat energy the water gained (q). 2/4 q=? m = 1000 g c = 4.184 J/g°C T = 2°C q = mcT q = (1000g) (4.184 J/g °C) (2 °C) the heat gained is 8368 J (8.368 KJ) (1. Solve) B. Assume that the heat energy gained by the water is equal to the heat energy lost by the aluminum. Use the specific heat equation to solve for the specific heat of aluminum. (Hint: Because heat energy is lost, the value of q is negative.) q = mcT ----------- (over/divided by) TT c = q / mT = - 8368 J / (125 g) (-74.95 °C) = 0.893 J/gºC 2. Calculate: Use the Gizmo to mix 200 g of copper at 100 °C with 1,000 g of water at 20 °C. 21.42 °C A. What is the final temperature? (2. Calculate) B. Calculate the temperature change of each substance by subtracting the initial temperature from the final temperature. T water: 21.42 °C - 20.0 °C = 1.42 °C T copper: 21.42 °C - 100 °C = -78.58 °C (2. Calculate) C. How much heat energy (q) did the water gain? q = mcT = (1000g) (4.184 J/g °C) (1.42 °C) = 5941 J (2. Calculate) D. Now solve for the specific heat (c) of copper c = q / mT = - 5941 J / (200g) (-78.58 °C ) = 0.378 J/g °C 3. Calculate: Use the Gizmo to mix 200 g of granite at 100 °C with 1,000 g of water at 20 °C. 22.93 °C A. What is the final temperature? (3. Calculate) B. Calculate the temperature change of each substance by subtracting the initial temperature from the final temperature. T water: 22.93 °C - 20 = 2.93 °C T granite: 22.93 °C - 100 °C = - 77.07 °C (3. Calculate) C: How much heat energy (q) did the water gain? q = mcT = (1000g) (4.184 J/g °C) (2.93 °C) = 12259 J (3. Calculate) D. Now solve for the specific heat (c) of granite c = q / mT = -12259 J / (200g) (-77.07) = 0.795 J/g °C A: 20.49°C B: T water: 20.49°C - 20 = 0.49°C T lead: 20.49°C - 100°C = -79.51 (3. Calculate) E: Repeat steps A through D to find the specific heat (c) of lead C: q = mcT = (1000g) (4.184 J/g °C) (0.49 °C) = 2050 J D: c = q / mT = -2050 J / (200g) (-79.51) = 0.129 J/g °C specific heat (c) of lead: 0.129 J/g °C 4. Challenge: Use the specific heat capacity that you calculated for granite to determine how many grams of granite at the initial temperature of 80 °C must mix with 3,000 g of water at the initial temperature of 20 °C to result in a final system temperature of 20.45 °C. 3/4 heat gained by water = heat lost by granite q = -q (m water) (c water) (T) = (m granite) (c granite) (T) m granite = (m water) (c water) (T) / (c granite) (T) m granite = (3000g) (4.184 J/g °C) (0.45°C) / (0.795 J/g °C) (-59.55°C) m granite = 5648.4 g / 47.34225 m granite = 119.3 g Mass of granite = 119 g 5. Extend your thinking: In addition to calculating specific heat capacities, some calorimeters can be used to determine how much energy is in food. The energy in food is usually expressed in calories or kilocalories (Calories). A calorie is the amount of energy needed to change the temperature of 1 g of water by 1 C. There are 1,000 calories in a Calorie. 1 cal / g°C = 4.184 J/g °C 1 cal = 4.184 J A. How many joules are in 1 calorie? (The specific heat of water is 4.184 J/g °C.) (5. Extend your thinking) B. Suppose a snack bar is burned in a calorimeter and heats 2,000 g water by 20 °C. How much heat energy was released? (Hint: Use the specific heat equation.) Give your answer in both joules and calories. q = mcT = (2000g) (4.184 J/g °C) (20°C ) = 167360 J = 40,000 cal 40 kilocalories (5. Extend your thinking) C. How many kilocalories (Calories) does the snack bar contain? 4/4 167360 J = 40,000 calories 1000 calories = 1 kilocalories 40,000 calories = 40 kilocalories